Cerebellar Ataxia
Ataxia
Spinocerebellar Ataxias
Spinocerebellar Degenerations
Friedreich Ataxia
Gait Ataxia
Ataxia Telangiectasia
Cerebellum
Olivopontocerebellar Atrophies
Stiff-Person Syndrome
Myoclonic Cerebellar Dyssynergia
Cerebellar Diseases
Pedigree
Reflex, Abnormal
Apraxias
Machado-Joseph Disease
Age of Onset
Genes, Dominant
Trinucleotide Repeats
Nystagmus, Pathologic
Foot Deformities
Multiple System Atrophy
Magnetic Resonance Imaging
Ocular Motility Disorders
Ataxia Telangiectasia Mutated Proteins
Gliadin
Trinucleotide Repeat Expansion
Glutamate Decarboxylase
Atrophy
Paraneoplastic Cerebellar Degeneration
Chromosomes, Human, Pair 19
Dysarthria
Anticipation, Genetic
Optic Atrophy
Mutation
Ophthalmoplegia
Myoclonus
Orphan Drug Production
Rare Diseases
Genetics of the SCA6 gene in a large family segregating an autosomal dominant "pure" cerebellar ataxia. (1/449)
Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant cerebellar degeneration caused by the expansion of a CAG trinucleotide repeat in the CACNA1A gene. Mutations in patients are characterised by expanded alleles of between 21 and 30 repeat units and by extreme gonadal stability when transmitted from parents to children. We have investigated the SCA6 mutation in a large Spanish kindred in which previously reported spinocerebellar SCA genes and loci had been excluded. We observed a 23 CAG repeat expanded allele in the 13 clinically affected subjects and in three out of 10 presymptomatic at risk subjects. Transmission of the mutant allele was stable in six parent to child pairs and in 29 meioses through the pedigree. Linkage analysis with the SCA6-CAG polymorphism and marker D19S221 confirmed the location of SCA6 on chromosome 19p13. The molecular findings in this large family confirm the expansion of the CAG repeat in the CACNA1A gene as the cause of SCA6 and the high meiotic stability of the repeat. (+info)Juvenile nephronophthisis associated with retinal pigmentary dystrophy, cerebellar ataxia, and skeletal abnormalities. (2/449)
A boy aged 9 3/4 years with interstitial nephritis, retinal pigmentary dystrophy, cerebellar ataxia, and skeletal abnormalities is described. The association may be due to a new genetic disorder, since 2 similar cases have been reported. (+info)Mutation of a putative mitochondrial iron transporter gene (ABC7) in X-linked sideroblastic anemia and ataxia (XLSA/A). (3/449)
X-linked sideroblastic anemia and ataxia (XLSA/A) is a recessive disorder characterized by an infantile to early childhood onset of non-progressive cerebellar ataxia and mild anemia with hypochromia and microcytosis. A gene encoding an ATP-binding cassette (ABC) transporter was mapped to Xq13, a region previously shown by linkage analysis to harbor the XLSA/A gene. This gene, ABC7, is an ortholog of the yeast ATM1 gene whose product localizes to the mitochondrial inner membrane and is involved in iron homeostasis. The full-length ABC7 cDNA was cloned and the entire coding region screened for mutations in a kindred in which five male members manifested XLSA/A. An I400M variant was identified in a predicted transmembrane segment of the ABC7 gene in patients with XLSA/A. The mutation was shown to segregate with the disease in the family and was not detected in at least 600 chromosomes of general population controls. Introduction of the corresponding mutation into the Saccharomyces cerevisiae ATM1 gene resulted in a partial loss of function of the yeast Atm1 protein. In addition, the human wild-type ABC7 protein was able to complement ATM1 deletion in yeast. These data indicate that ABC7 is the causal gene of XLSA/A and that XLSA/A is a mitochondrial disease caused by a mutation in the nuclear genome. (+info)Acute cerebellar ataxia with human parvovirus B19 infection. (4/449)
A 2 year old boy developed acute cerebellar ataxia in association with erythema infectiosum. During the disease, genomic DNA and antibodies against human parvovirus B19 were detected in serum but not in cerebrospinal fluid. Parvovirus B19 associated acute cerebellar ataxia might occur due to transient vascular reaction in the cerebellum during infection. (+info)Molecular and clinical study of 18 families with ADCA type II: evidence for genetic heterogeneity and de novo mutation. (5/449)
The SCA7 mutation has been found in 54 patients and 7 at-risk subjects from 17 families who have autosomal dominant cerebellar ataxia (ADCA) II with progressive pigmentary maculopathy. In one isolated case, haplotype reconstruction through three generations confirmed a de novo mutation owing to paternal meiotic instability. Different disease-associated haplotypes segregated among the SCA7-positive kindreds, which indicated a multiple origin of the mutation. One family with the clinical phenotype of ADCA type II did not have the CAG expansion that indicated locus heterogeneity. The distribution of the repeat size in 944 independent normal chromosomes from controls, unaffected at-risk subjects, and one affected individual fell into two ranges. The majority of the alleles were in the first range of 7-19 CAG repeats. A second range could be identified with 28-35 repeats, and we provide evidence that these repeats represent intermediate alleles that are prone to further expansion. The repeat size of the pathological allele, the widest reported for all CAG-repeat disorders, ranged from 37 to approximately 220. The repeat size showed significant negative correlation with both age at onset and age at death. Analysis of the clinical features in the patients with SCA7 confirmed that the most frequently associated features are pigmentary maculopathy, pyramidal tract involvement, and slow saccades. The subjects with <49 repeats tended to have a less complicated neurological phenotype and a longer disease duration, whereas the converse applied to subjects with >/=49 repeats. The degree of instability during meiotic transmission was greater than in all other CAG-repeat disorders and was particularly striking in paternal transmission, in which a median increase in repeat size of 6 and an interquartile range of 12 were observed, versus a median increase of 3 and interquartile range of 3.5 in maternal transmission. (+info)Decreased cerebellar blood flow in postinfectious acute cerebellar ataxia. (6/449)
OBJECTIVE: The aim of the present study was to evaluate the regional cerebral blood flow (rCBF) in patients with postinfectious acute cerebellar ataxia using single photon emission computed tomography (SPECT). METHODS: Five children with postinfectious acute cerebellar ataxia and five control subjects were examined. The distribution of rCBF was measured by SPECT imaging after intravenous administration of 123I-IMP (111 MBq). The rCBF ratio-defined as the ratio of rCBF in the region of interest (ROI) to that in the occipital cortex-was calculated for each cortical and subcortical ROI. The mean rCBF ratio of each region was then compared between the ataxic and control subjects. These patients and all control subjects were also evaluated using MRI. RESULTS: The rCBF ratio was significantly lower in the cerebellum of the ataxic patients than in the cerebellum of the control subjects (p<0.05). No abnormal cerebellar morphology and no abnormal signal intensities were found on MRI. CONCLUSION: 123I-IMP SPECT clearly demonstrated the decreased rCBF in the cerebellum of all patients with postinfectious acute cerebellar ataxia. (+info)Trinucleotide repeat expansion of spinocerebellar ataxia (SCA1) found in a Chinese family. (7/449)
OBJECTIVE: To investigate the gene mutation and the ratio of the spinocerebellar ataxia type 1 (SCA1) in Chinese patients with autosomal dominant spinocerebellar ataxia (ADSCA). METHOD: The family material and DNA samples were collected from thirteen families with ADSCA. To determine the characteristics of the CAG trinucleotide repeats in SCA1 gene, the PCR products of the Rep1 and Rep2 primers were analyzed, and the bands with CAG repeat expansion were cloned by PCR2. 1 vector and sequenced. RESULTS: One family was found to have an expanded CAG repeat in the 13 families with ADSCA. The clinically affected individual was heterozygous with one disease allele being 55 CAG repeats, whereas the mean size of the CAG repeats on 104 chromosomes generated from unrelated control Chinese individuals is 29.3 (ranging from 18 to 34). CONCLUSIONS: The frequency of the SCA1 mutation is about 7% in the 13 Chinese families with ADSCA, suggesting that this type of genetic defect is not the main cause involved in the pathogenesis of ADSCA in China. Since the mutation has also been found in Caucasian, Japanese, Malaysian, and Bangladeshi kindreds, it is suggested that this genetic defect may well have multiple origins in different ethnic groups. (+info)Comparative analysis of gait in Parkinson's disease, cerebellar ataxia and subcortical arteriosclerotic encephalopathy. (8/449)
Quantitative gait analysis has been used to elucidate characteristic features of neurological gait disturbances. Although a number of studies compared single patient groups with controls, there are only a few studies comparing gait parameters between patients with different neurological disorders affecting gait. In the present study, gait parameters were compared between control subjects, patients with parkinsonian gait due to idiopathic Parkinson's disease, subjects suffering from cerebellar ataxia and patients with gait disturbance due to subcortical arteriosclerotic encephalopathy. In addition to recording of baseline parameters during preferred walking velocity, subjects were required to vary velocity from very slow to very fast. Values of velocity and stride length from each subject were then used for linear regression analysis. Whereas all patient groups showed slower walking velocity and reduced step length compared with healthy controls when assessed during preferred walking, patients with ataxia and subcortical arteriosclerotic encephalopathy had, in addition, increased variability of amplitude and timing of steps. Regression analysis showed that with changing velocity, subjects with Parkinson's disease changed their stride length in the same proportion as that measured in controls. In contrast, patients with ataxia and subcortical arteriosclerotic encephalopathy had a disproportionate contribution of stride length when velocity was increased. Whereas the findings in patients with Parkinson's disease can be explained as a reduction of force gain, the observations for patients with ataxia and subcortical arteriosclerotic encephalopathy reflect an altered spatiotemporal gait strategy in order to compensate for instability. The similarity of gait disturbance in subcortical arteriosclerotic encephalopathy and cerebellar ataxia suggests common mechanisms. (+info)Cerebellar ataxia is a type of ataxia, which refers to a group of disorders that cause difficulties with coordination and movement. Cerebellar ataxia specifically involves the cerebellum, which is the part of the brain responsible for maintaining balance, coordinating muscle movements, and regulating speech and eye movements.
The symptoms of cerebellar ataxia may include:
* Unsteady gait or difficulty walking
* Poor coordination of limb movements
* Tremors or shakiness, especially in the hands
* Slurred or irregular speech
* Abnormal eye movements, such as nystagmus (rapid, involuntary movement of the eyes)
* Difficulty with fine motor tasks, such as writing or buttoning a shirt
Cerebellar ataxia can be caused by a variety of underlying conditions, including:
* Genetic disorders, such as spinocerebellar ataxia or Friedreich's ataxia
* Brain injury or trauma
* Stroke or brain hemorrhage
* Infections, such as meningitis or encephalitis
* Exposure to toxins, such as alcohol or certain medications
* Tumors or other growths in the brain
Treatment for cerebellar ataxia depends on the underlying cause. In some cases, there may be no cure, and treatment is focused on managing symptoms and improving quality of life. Physical therapy, occupational therapy, and speech therapy can help improve coordination, balance, and communication skills. Medications may also be used to treat specific symptoms, such as tremors or muscle spasticity. In some cases, surgery may be recommended to remove tumors or repair damage to the brain.
Ataxia is a medical term that refers to a group of disorders affecting coordination, balance, and speech. It is characterized by a lack of muscle control during voluntary movements, causing unsteady or awkward movements, and often accompanied by tremors. Ataxia can affect various parts of the body, such as the limbs, trunk, eyes, and speech muscles. The condition can be congenital or acquired, and it can result from damage to the cerebellum, spinal cord, or sensory nerves. There are several types of ataxia, including hereditary ataxias, degenerative ataxias, cerebellar ataxias, and acquired ataxias, each with its own specific causes, symptoms, and prognosis. Treatment for ataxia typically focuses on managing symptoms and improving quality of life, as there is no cure for most forms of the disorder.
Spinocerebellar ataxias (SCAs) are a group of genetic disorders that affect the cerebellum, which is the part of the brain responsible for coordinating muscle movements. SCAs are characterized by progressive problems with balance, speech, and coordination. They are caused by mutations in various genes that result in the production of abnormal proteins that accumulate in neurons, leading to their degeneration.
There are over 40 different types of SCAs, each caused by a different genetic mutation. Some of the more common types include SCA1, SCA2, SCA3, SCA6, and SCA7. The symptoms and age of onset can vary widely depending on the type of SCA.
In addition to problems with coordination and balance, people with SCAs may also experience muscle weakness, stiffness, tremors, spasticity, and difficulty swallowing or speaking. Some types of SCAs can also cause visual disturbances, hearing loss, and cognitive impairment. Currently, there is no cure for SCAs, but treatments such as physical therapy, speech therapy, and medications can help manage the symptoms.
Spinocerebellar degenerations (SCDs) are a group of genetic disorders that primarily affect the cerebellum, the part of the brain responsible for coordinating muscle movements, and the spinal cord. These conditions are characterized by progressive degeneration or loss of nerve cells in the cerebellum and/or spinal cord, leading to various neurological symptoms.
SCDs are often inherited in an autosomal dominant manner, meaning that only one copy of the altered gene from either parent is enough to cause the disorder. The most common type of SCD is spinocerebellar ataxia (SCA), which includes several subtypes (SCA1, SCA2, SCA3, etc.) differentiated by their genetic causes and specific clinical features.
Symptoms of spinocerebellar degenerations may include:
1. Progressive ataxia (loss of coordination and balance)
2. Dysarthria (speech difficulty)
3. Nystagmus (involuntary eye movements)
4. Oculomotor abnormalities (problems with eye movement control)
5. Tremors or other involuntary muscle movements
6. Muscle weakness and spasticity
7. Sensory disturbances, such as numbness or tingling sensations
8. Dysphagia (difficulty swallowing)
9. Cognitive impairment in some cases
The age of onset, severity, and progression of symptoms can vary significantly among different SCD subtypes and individuals. Currently, there is no cure for spinocerebellar degenerations, but various supportive treatments and therapies can help manage symptoms and improve quality of life.
Friedreich Ataxia is a genetic disorder that affects the nervous system and causes issues with movement. It is characterized by progressive damage to the nerves (neurons) in the spinal cord and peripheral nerves, which can lead to problems with muscle coordination, gait, speech, and hearing. The condition is also associated with heart disorders, diabetes, and vision impairment.
Friedreich Ataxia is caused by a mutation in the FXN gene, which provides instructions for making a protein called frataxin. This protein plays a role in the production of energy within cells, particularly in the mitochondria. The mutation in the FXN gene leads to reduced levels of frataxin, which can cause nerve damage and other symptoms associated with Friedreich Ataxia.
The condition typically begins in childhood or early adulthood and progresses over time, often leading to significant disability. There is currently no cure for Friedreich Ataxia, but treatments are available to help manage the symptoms and improve quality of life.
Gait ataxia is a type of ataxia, which refers to a lack of coordination or stability, specifically involving walking or gait. It is characterized by an unsteady, uncoordinated, and typically wide-based gait pattern. This occurs due to dysfunction in the cerebellum or its connecting pathways, responsible for maintaining balance and coordinating muscle movements.
In gait ataxia, individuals often have difficulty with controlling the rhythm and pace of their steps, tend to veer or stagger off course, and may display a reeling or stumbling motion while walking. They might also have trouble performing rapid alternating movements like quickly tapping their foot or heel. These symptoms are usually worse when the person is tired or attempting to walk in the dark.
Gait ataxia can be caused by various underlying conditions, including degenerative neurological disorders (e.g., cerebellar atrophy, multiple sclerosis), stroke, brain injury, infection (e.g., alcoholism, HIV), or exposure to certain toxins. Proper diagnosis and identification of the underlying cause are essential for effective treatment and management of gait ataxia.
Ataxia telangiectasia is a rare, inherited genetic disorder that affects the nervous system, immune system, and overall development. The condition is characterized by progressive difficulty with coordination and balance (ataxia), as well as the development of small, dilated blood vessels (telangiectasias) on the skin and eyes.
The underlying cause of ataxia telangiectasia is a mutation in the ATM gene, which provides instructions for making a protein that plays a critical role in DNA repair and maintaining genetic stability. When this gene is mutated, cells are unable to properly repair damaged DNA, leading to an increased risk of cancer and other health problems.
Individuals with ataxia telangiectasia typically begin to show symptoms during early childhood, with progressive difficulties in coordination and balance, slurred speech, and recurrent respiratory infections due to weakened immune function. Over time, these symptoms can worsen, leading to significant disability and reduced life expectancy.
There is currently no cure for ataxia telangiectasia, and treatment is focused on managing the symptoms and complications of the condition. This may include physical therapy, speech therapy, and medications to help control infections and other health problems.
The cerebellum is a part of the brain that lies behind the brainstem and is involved in the regulation of motor movements, balance, and coordination. It contains two hemispheres and a central portion called the vermis. The cerebellum receives input from sensory systems and other areas of the brain and spinal cord and sends output to motor areas of the brain. Damage to the cerebellum can result in problems with movement, balance, and coordination.
Olivopontocerebellar atrophies (OPCA) are a group of rare, progressive neurodegenerative disorders that primarily affect the cerebellum, olive (inferior olivary nucleus), and pons in the brainstem. The condition is characterized by degeneration and atrophy of these specific areas, leading to various neurological symptoms.
The term "olivopontocerebellar atrophies" encompasses several subtypes, including:
1. Hereditary spastic paraplegia with cerebellar ataxia (SPG/ATA) - Autosomal dominant or recessive inheritance pattern.
2. Hereditary dentatorubral-pallidoluysian atrophy (DRPLA) - Autosomal dominant inheritance pattern.
3. Idiopathic OPCA - No known genetic cause, possibly related to environmental factors or spontaneous mutations.
Symptoms of olivopontocerebellar atrophies may include:
* Progressive cerebellar ataxia (gait and limb incoordination)
* Dysarthria (slurred speech)
* Oculomotor abnormalities (nystagmus, gaze palsy)
* Spasticity (stiffness and rigidity of muscles)
* Dysphagia (difficulty swallowing)
* Tremors or dystonia (involuntary muscle contractions)
Diagnosis typically involves a combination of clinical examination, neuroimaging studies (MRI), genetic testing, and exclusion of other possible causes. Currently, there is no cure for olivopontocerebellar atrophies, but supportive care can help manage symptoms and improve quality of life.
Stiff-Person Syndrome (SPS) is a rare neurological disorder characterized by fluctuating muscle rigidity in the trunk and limbs and a heightened sensitivity to stimuli such as touch, sound, and emotional distress, which can trigger muscle spasms. The symptoms can significantly affect a person's ability to perform daily activities and can lead to frequent falls and injuries. SPS is often associated with antibodies against glutamic acid decarboxylase (GAD), an enzyme involved in the production of a neurotransmitter called gamma-aminobutyric acid (GABA) that helps regulate muscle movement. The exact cause of SPS remains unknown, but it is thought to involve both autoimmune and genetic factors.
Recessive genes refer to the alleles (versions of a gene) that will only be expressed when an individual has two copies of that particular allele, one inherited from each parent. If an individual inherits one recessive allele and one dominant allele for a particular gene, the dominant allele will be expressed and the recessive allele will have no effect on the individual's phenotype (observable traits).
Recessive genes can still play a role in determining an individual's genetic makeup and can be passed down through generations even if they are not expressed. If two carriers of a recessive gene have children, there is a 25% chance that their offspring will inherit two copies of the recessive allele and exhibit the associated recessive trait.
Examples of genetic disorders caused by recessive genes include cystic fibrosis, sickle cell anemia, and albinism.
Myoclonic cerebellar dyssynergia is not a widely recognized or formally defined medical term. However, based on its individual components, it can be inferred to refer to a neurological condition characterized by:
1. Myoclonus: These are sudden, involuntary jerking movements of a muscle or group of muscles. They typically occur as a result of hyperexcitability of the neurons in the brain that control movement (motor neurons).
2. Cerebellar: The cerebellum is a part of the brain responsible for coordinating muscle movements, maintaining posture and balance, and fine-tuning motor skills. When a condition is described as "cerebellar," it implies that there is some dysfunction or abnormality in this region of the brain.
3. Dyssynergia: This term refers to a lack of coordination between muscles and muscle groups during voluntary movements. It can result from damage to the cerebellum or other parts of the nervous system involved in motor control.
Therefore, myoclonic cerebellar dyssynergia could be interpreted as a condition characterized by involuntary muscle jerks (myoclonus) and impaired coordination of voluntary movements (dyssynergia), likely due to cerebellar dysfunction. However, it is essential to consult with a medical professional for an accurate diagnosis and treatment plan if you or someone else experiences symptoms that may align with this description.
Cerebellar diseases refer to a group of medical conditions that affect the cerebellum, which is the part of the brain located at the back of the head, below the occipital lobe and above the brainstem. The cerebellum plays a crucial role in motor control, coordination, balance, and some cognitive functions.
Cerebellar diseases can be caused by various factors, including genetics, infections, tumors, stroke, trauma, or degenerative processes. These conditions can result in a wide range of symptoms, such as:
1. Ataxia: Loss of coordination and unsteady gait
2. Dysmetria: Inability to judge distance and force while performing movements
3. Intention tremors: Shaking or trembling that worsens during purposeful movements
4. Nystagmus: Rapid, involuntary eye movement
5. Dysarthria: Speech difficulty due to muscle weakness or incoordination
6. Hypotonia: Decreased muscle tone
7. Titubation: Rhythmic, involuntary oscillations of the head and neck
8. Cognitive impairment: Problems with memory, attention, and executive functions
Some examples of cerebellar diseases include:
1. Ataxia-telangiectasia
2. Friedrich's ataxia
3. Multiple system atrophy (MSA)
4. Spinocerebellar ataxias (SCAs)
5. Cerebellar tumors, such as medulloblastomas or astrocytomas
6. Infarctions or hemorrhages in the cerebellum due to stroke or trauma
7. Infections, such as viral encephalitis or bacterial meningitis
8. Autoimmune disorders, like multiple sclerosis (MS) or paraneoplastic syndromes
9. Metabolic disorders, such as Wilson's disease or phenylketonuria (PKU)
10. Chronic alcoholism and withdrawal
Treatment for cerebellar diseases depends on the underlying cause and may involve medications, physical therapy, surgery, or supportive care to manage symptoms and improve quality of life.
I must clarify that the term "pedigree" is not typically used in medical definitions. Instead, it is often employed in genetics and breeding, where it refers to the recorded ancestry of an individual or a family, tracing the inheritance of specific traits or diseases. In human genetics, a pedigree can help illustrate the pattern of genetic inheritance in families over multiple generations. However, it is not a medical term with a specific clinical definition.
An abnormal reflex in a medical context refers to an involuntary and exaggerated response or lack of response to a stimulus that is not expected in the normal physiological range. These responses can be indicative of underlying neurological disorders or damage to the nervous system. Examples include hyperreflexia (overactive reflexes) and hyporeflexia (underactive reflexes). The assessment of reflexes is an important part of a physical examination, as it can provide valuable information about the functioning of the nervous system.
Apraxia is a motor disorder characterized by the inability to perform learned, purposeful movements despite having the physical ability and mental understanding to do so. It is not caused by weakness, paralysis, or sensory loss, and it is not due to poor comprehension or motivation.
There are several types of apraxias, including:
1. Limb-Kinematic Apraxia: This type affects the ability to make precise movements with the limbs, such as using tools or performing complex gestures.
2. Ideomotor Apraxia: In this form, individuals have difficulty executing learned motor actions in response to verbal commands or visual cues, but they can still perform the same action when given the actual object to use.
3. Ideational Apraxia: This type affects the ability to sequence and coordinate multiple steps of a complex action, such as dressing oneself or making coffee.
4. Oral Apraxia: Also known as verbal apraxia, this form affects the ability to plan and execute speech movements, leading to difficulties with articulation and speech production.
5. Constructional Apraxia: This type impairs the ability to draw, copy, or construct geometric forms and shapes, often due to visuospatial processing issues.
Apraxias can result from various neurological conditions, such as stroke, brain injury, dementia, or neurodegenerative diseases like Parkinson's disease and Alzheimer's disease. Treatment typically involves rehabilitation and therapy focused on retraining the affected movements and compensating for any residual deficits.
Machado-Joseph Disease (MJD) is a genetic disorder that affects the part of the brain that controls movement. It is also known as spinocerebellar ataxia type 3 (SCA3). MJD is characterized by progressive problems with coordination, speech, and swallowing, along with muscle stiffness, tremors, and in some cases, eye movement abnormalities.
MJD is caused by a mutation in the ATXN3 gene, which results in an expanded CAG repeat sequence. This genetic defect leads to the production of an abnormal protein that accumulates in nerve cells, causing them to die. The severity and age of onset of MJD can vary widely, even within families, but symptoms typically begin between the ages of 10 and 60.
MJD is inherited in an autosomal dominant manner, meaning that a child has a 50% chance of inheriting the disease-causing mutation from an affected parent. Currently, there is no cure for MJD, but treatments can help manage symptoms and improve quality of life.
The "age of onset" is a medical term that refers to the age at which an individual first develops or displays symptoms of a particular disease, disorder, or condition. It can be used to describe various medical conditions, including both physical and mental health disorders. The age of onset can have implications for prognosis, treatment approaches, and potential causes of the condition. In some cases, early onset may indicate a more severe or progressive course of the disease, while late-onset symptoms might be associated with different underlying factors or etiologies. It is essential to provide accurate and precise information regarding the age of onset when discussing a patient's medical history and treatment plan.
Purkinje cells are a type of neuron located in the cerebellar cortex, which is the outer layer of the cerebellum, a part of the brain that plays a crucial role in motor control and coordination. These cells have large branching dendrites and receive input from many other neurons, particularly granule cells. The axons of Purkinje cells form the principal output pathway of the cerebellar cortex, synapsing with deep cerebellar nuclei. They are named after Johannes Evangelista Purkinje, a Czech physiologist who first described them in 1837.
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
I apologize, but I am not able to provide a medical definition for "Bromisovalum" because it is not a recognized or validated medication or substance in the field of medicine. It is possible that there may be a spelling error or typo in the term you provided. If you have more information about what you are looking for, I will do my best to help you find the correct information.
Dominant genes refer to the alleles (versions of a gene) that are fully expressed in an individual's phenotype, even if only one copy of the gene is present. In dominant inheritance patterns, an individual needs only to receive one dominant allele from either parent to express the associated trait. This is in contrast to recessive genes, where both copies of the gene must be the recessive allele for the trait to be expressed. Dominant genes are represented by uppercase letters (e.g., 'A') and recessive genes by lowercase letters (e.g., 'a'). If an individual inherits one dominant allele (A) from either parent, they will express the dominant trait (A).
Trinucleotide repeats refer to a specific type of DNA sequence expansion where a particular trinucleotide (a sequence made up of three nucleotides) is repeated multiple times. In normal genomic DNA, these repeats are usually present in a relatively stable and consistent range. However, when the number of repeats exceeds a certain threshold, it can result in an unstable genetic variant known as a trinucleotide repeat expansion.
These expansions can occur in various genes and are associated with several neurogenetic disorders, such as Huntington's disease, myotonic dystrophy, fragile X syndrome, and Friedreich's ataxia. The length of the trinucleotide repeat tends to expand further in subsequent generations, which can lead to anticipation – an earlier age of onset and increased severity of symptoms in successive generations.
The most common trinucleotide repeats involve CAG (cytosine-adenine-guanine) or CTG (cytosine-thymine-guanine) repeats, although other combinations like CGG, GAA, and GCT can also be involved. These repeat expansions can result in altered gene function, protein misfolding, aggregation, and toxicity, ultimately leading to the development of neurodegenerative diseases and other clinical manifestations.
Pathological nystagmus is an abnormal, involuntary movement of the eyes that can occur in various directions (horizontal, vertical, or rotatory) and can be rhythmical or arrhythmic. It is typically a result of a disturbance in the vestibular system, central nervous system, or ocular motor pathways. Pathological nystagmus can cause visual symptoms such as blurred vision, difficulty with fixation, and oscillopsia (the sensation that one's surroundings are moving). The type, direction, and intensity of the nystagmus may vary depending on the underlying cause, which can include conditions such as brainstem or cerebellar lesions, multiple sclerosis, drug toxicity, inner ear disorders, and congenital abnormalities.
Foot deformities refer to abnormal changes in the structure and/or alignment of the bones, joints, muscles, ligaments, or tendons in the foot, leading to a deviation from the normal shape and function of the foot. These deformities can occur in various parts of the foot, such as the toes, arch, heel, or ankle, and can result in pain, difficulty walking, and reduced mobility. Some common examples of foot deformities include:
1. Hammertoes: A deformity where the toe bends downward at the middle joint, resembling a hammer.
2. Mallet toes: A condition where the end joint of the toe is bent downward, creating a mallet-like shape.
3. Claw toes: A combination of both hammertoes and mallet toes, causing all three joints in the toe to bend abnormally.
4. Bunions: A bony bump that forms on the inside of the foot at the base of the big toe, caused by the misalignment of the big toe joint.
5. Tailor's bunion (bunionette): A similar condition to a bunion but occurring on the outside of the foot, at the base of the little toe.
6. Flat feet (pes planus): A condition where the arch of the foot collapses, causing the entire sole of the foot to come into contact with the ground when standing or walking.
7. High arches (pes cavus): An excessively high arch that doesn't provide enough shock absorption and can lead to pain and instability.
8. Cavus foot: A condition characterized by a very high arch and tight heel cord, often leading to an imbalance in the foot structure and increased risk of ankle injuries.
9. Haglund's deformity: A bony enlargement on the back of the heel, which can cause pain and irritation when wearing shoes.
10. Charcot foot: A severe deformity that occurs due to nerve damage in the foot, leading to weakened bones, joint dislocations, and foot collapse.
Foot deformities can be congenital (present at birth) or acquired (develop later in life) due to various factors such as injury, illness, poor footwear, or abnormal biomechanics. Proper diagnosis, treatment, and management are essential for maintaining foot health and preventing further complications.
Multiple System Atrophy (MSA) is a rare, progressive neurodegenerative disorder that affects multiple systems in the body. It is characterized by a combination of symptoms including Parkinsonism (such as stiffness, slowness of movement, and tremors), cerebellar ataxia (lack of muscle coordination), autonomic dysfunction (problems with the autonomic nervous system which controls involuntary actions like heart rate, blood pressure, sweating, and digestion), and pyramidal signs (abnormalities in the corticospinal tracts that control voluntary movements).
The disorder is caused by the degeneration of nerve cells in various parts of the brain and spinal cord, leading to a loss of function in these areas. The exact cause of MSA is unknown, but it is thought to involve a combination of genetic and environmental factors. There is currently no cure for MSA, and treatment is focused on managing symptoms and improving quality of life.
Medical Definition:
Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.
Ocular motility disorders refer to a group of conditions that affect the movement of the eyes. These disorders can result from nerve damage, muscle dysfunction, or brain injuries. They can cause abnormal eye alignment, limited range of motion, and difficulty coordinating eye movements. Common symptoms include double vision, blurry vision, strabismus (crossed eyes), nystagmus (involuntary eye movement), and difficulty tracking moving objects. Ocular motility disorders can be congenital or acquired and may require medical intervention to correct or manage the condition.
Ataxia telangiectasia mutated (ATM) proteins are a type of protein that play a crucial role in the maintenance and repair of DNA in cells. The ATM gene produces these proteins, which are involved in several important cellular processes such as:
1. DNA damage response: When DNA is damaged, ATM proteins help to detect and respond to the damage by activating various signaling pathways that lead to DNA repair or apoptosis (programmed cell death) if the damage is too severe.
2. Cell cycle regulation: ATM proteins regulate the cell cycle by controlling checkpoints that ensure proper DNA replication and division. This helps prevent the propagation of cells with damaged DNA.
3. Telomere maintenance: ATM proteins help maintain telomeres, which are the protective caps at the ends of chromosomes. Telomeres shorten as cells divide, and when they become too short, cells can no longer divide and enter a state of senescence or die.
Mutations in the ATM gene can lead to Ataxia-telangiectasia (A-T), a rare inherited disorder characterized by neurological problems, immune system dysfunction, increased risk of cancer, and sensitivity to ionizing radiation. People with A-T have defective ATM proteins that cannot properly respond to DNA damage, leading to genomic instability and increased susceptibility to disease.
Gliadin is a protein fraction found in gluten, a complex protein that's present in certain grains such as wheat, barley, and rye. It is particularly known for its role in celiac disease, a disorder where the ingestion of gluten leads to an immune response that damages the lining of the small intestine.
Gliadin, along with another protein fraction called glutenin, makes up gluten. Gliadin is responsible for the elastic properties of dough. When water is added to flour and mixed, these proteins form a sticky network that gives dough its characteristic texture and allows it to rise and maintain its shape during baking.
In individuals with celiac disease, the immune system recognizes gliadin as a foreign invader and mounts an immune response against it. This response leads to inflammation and damage in the small intestine, preventing the absorption of nutrients from food. Over time, this can lead to various health complications if not properly managed through a gluten-free diet.
Trinucleotide Repeat Expansion is a genetic mutation where a sequence of three DNA nucleotides is repeated more frequently than what is typically found in the general population. In this type of mutation, the number of repeats can expand or increase from one generation to the next, leading to an increased risk of developing certain genetic disorders.
These disorders are often neurological and include conditions such as Huntington's disease, myotonic dystrophy, fragile X syndrome, and Friedreich's ataxia. The severity of these diseases can be related to the number of repeats present in the affected gene, with a higher number of repeats leading to more severe symptoms or an earlier age of onset.
It is important to note that not all trinucleotide repeat expansions will result in disease, and some people may carry these mutations without ever developing any symptoms. However, if the number of repeats crosses a certain threshold, it can lead to genetic instability and an increased risk of disease development.
Glutamate decarboxylase (GAD) is an enzyme that plays a crucial role in the synthesis of the neurotransmitter gamma-aminobutyric acid (GABA) in the brain. GABA is an inhibitory neurotransmitter that helps to balance the excitatory effects of glutamate, another neurotransmitter.
Glutamate decarboxylase catalyzes the conversion of glutamate to GABA by removing a carboxyl group from the glutamate molecule. This reaction occurs in two steps, with the enzyme first converting glutamate to glutamic acid semialdehyde and then converting that intermediate product to GABA.
There are two major isoforms of glutamate decarboxylase, GAD65 and GAD67, which differ in their molecular weight, subcellular localization, and function. GAD65 is primarily responsible for the synthesis of GABA in neuronal synapses, while GAD67 is responsible for the synthesis of GABA in the cell body and dendrites of neurons.
Glutamate decarboxylase is an important target for research in neurology and psychiatry because dysregulation of GABAergic neurotransmission has been implicated in a variety of neurological and psychiatric disorders, including epilepsy, anxiety, depression, and schizophrenia.
Atrophy is a medical term that refers to the decrease in size and wasting of an organ or tissue due to the disappearance of cells, shrinkage of cells, or decreased number of cells. This process can be caused by various factors such as disuse, aging, degeneration, injury, or disease.
For example, if a muscle is immobilized for an extended period, it may undergo atrophy due to lack of use. Similarly, certain medical conditions like diabetes, cancer, and heart failure can lead to the wasting away of various tissues and organs in the body.
Atrophy can also occur as a result of natural aging processes, leading to decreased muscle mass and strength in older adults. In general, atrophy is characterized by a decrease in the volume or weight of an organ or tissue, which can have significant impacts on its function and overall health.
Paraneoplastic cerebellar degeneration (PCD) is a rare disorder characterized by progressive damage to the cerebellum, the part of the brain responsible for coordinating muscle movements. It is considered a paraneoplastic syndrome, which means it is caused by an abnormal immune system response to a cancerous tumor (neoplasm) located elsewhere in the body.
In PCD, antibodies produced by the immune system to fight the tumor mistakenly attack proteins in the cerebellum that are similar to those found in the tumor. This leads to inflammation and degeneration of the Purkinje cells, a type of neuron critical for maintaining balance and coordinating movements.
PCD can present with symptoms such as unsteady gait, loss of coordination, slurred speech, nystagmus (involuntary eye movement), and tremors. These symptoms often develop rapidly, over the course of days to weeks, and may progress even after the tumor has been removed or treated.
PCD is associated with several types of cancers, including small cell lung cancer, breast cancer, ovarian cancer, Hodgkin's lymphoma, and others. Early diagnosis and treatment of the underlying cancer are essential to slowing down the progression of PCD and improving outcomes.
Human chromosome pair 19 refers to a group of 19 identical chromosomes that are present in every cell of the human body, except for the sperm and egg cells which contain only 23 chromosomes. Chromosomes are thread-like structures that carry genetic information in the form of DNA (deoxyribonucleic acid) molecules.
Each chromosome is made up of two arms, a shorter p arm and a longer q arm, separated by a centromere. Human chromosome pair 19 is an acrocentric chromosome, which means that the centromere is located very close to the end of the short arm (p arm).
Chromosome pair 19 contains approximately 58 million base pairs of DNA and encodes for around 1,400 genes. It is one of the most gene-dense chromosomes in the human genome, with many genes involved in important biological processes such as metabolism, immunity, and neurological function.
Abnormalities in chromosome pair 19 have been associated with various genetic disorders, including Sotos syndrome, which is characterized by overgrowth, developmental delay, and distinctive facial features, and Smith-Magenis syndrome, which is marked by intellectual disability, behavioral problems, and distinct physical features.
Dysarthria is a motor speech disorder that results from damage to the nervous system, particularly the brainstem or cerebellum. It affects the muscles used for speaking, causing slurred, slow, or difficult speech. The specific symptoms can vary depending on the underlying cause and the extent of nerve damage. Treatment typically involves speech therapy to improve communication abilities.
Genetic anticipation is a phenomenon observed in certain genetic disorders where the severity and/or age of onset of the disease tend to worsen in successive generations. This occurs due to an expansion of triplet repeat sequences (sequences of three consecutive DNA base pairs) in the affected gene, which can lead to an increased production of abnormal proteins associated with the disorder. The expanded repeats are more likely to be inherited when the parent who carries them is a female. Examples of genetic disorders that exhibit anticipation include Huntington's disease, myotonic dystrophy, and fragile X syndrome.
Optic atrophy is a medical term that refers to the degeneration and shrinkage (atrophy) of the optic nerve, which transmits visual information from the eye to the brain. This condition can result in various vision abnormalities, including loss of visual acuity, color vision deficiencies, and peripheral vision loss.
Optic atrophy can occur due to a variety of causes, such as:
* Traumatic injuries to the eye or optic nerve
* Glaucoma
* Optic neuritis (inflammation of the optic nerve)
* Ischemic optic neuropathy (reduced blood flow to the optic nerve)
* Compression or swelling of the optic nerve
* Hereditary or congenital conditions affecting the optic nerve
* Toxins and certain medications that can damage the optic nerve.
The diagnosis of optic atrophy typically involves a comprehensive eye examination, including visual acuity testing, refraction assessment, slit-lamp examination, and dilated funduscopic examination to evaluate the health of the optic nerve. In some cases, additional diagnostic tests such as visual field testing, optical coherence tomography (OCT), or magnetic resonance imaging (MRI) may be necessary to confirm the diagnosis and determine the underlying cause.
There is no specific treatment for optic atrophy, but addressing the underlying cause can help prevent further damage to the optic nerve. In some cases, vision rehabilitation may be recommended to help patients adapt to their visual impairment.
A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.
Ophthalmoplegia is a medical term that refers to the paralysis or weakness of the eye muscles, which can result in double vision (diplopia) or difficulty moving the eyes. It can be caused by various conditions, including nerve damage, muscle disorders, or neurological diseases such as myasthenia gravis or multiple sclerosis. Ophthalmoplegia can affect one or more eye muscles and can be partial or complete. Depending on the underlying cause, ophthalmoplegia may be treatable with medications, surgery, or other interventions.
Myoclonus is a medical term that describes a quick, involuntary jerking muscle spasm. These spasms can happen once or repeat in a series, and they can range from mild to severe in nature. Myoclonus can affect any muscle in the body and can be caused by several different conditions, including certain neurological disorders, injuries, or diseases. In some cases, myoclonus may occur without an identifiable cause.
There are various types of myoclonus, classified based on their underlying causes, patterns of occurrence, and associated symptoms. Some common forms include:
1. Action myoclonus: Occurs during voluntary muscle movements
2. Stimulus-sensitive myoclonus: Triggered by external or internal stimuli, such as touch, sound, or light
3. Physiological myoclonus: Normal muscle jerks that occur during sleep onset (hypnic jerks) or during sleep (nocturnal myoclonus)
4. Reflex myoclonus: Result of a reflex arc activation due to a peripheral nerve stimulation
5. Epileptic myoclonus: Part of an epilepsy syndrome, often involving the brainstem or cortex
6. Symptomatic myoclonus: Occurs as a result of an underlying medical condition, such as metabolic disorders, infections, or neurodegenerative diseases
Treatment for myoclonus depends on the specific type and underlying cause. Medications, physical therapy, or lifestyle modifications may be recommended to help manage symptoms and improve quality of life.
An "Orphan Drug" is a pharmaceutical agent that is developed to treat a rare medical condition, disorder, or disease that affects a small number of people in comparison to other conditions. In the United States, this is defined as a condition or disease that affects fewer than 200,000 people nationwide. Due to the limited market for these drugs, pharmaceutical companies are often reluctant to invest in their development and production.
"Orphan Drug Production," therefore, refers to the manufacturing process of these rare disease treatments. To encourage the development and production of orphan drugs, governments and regulatory agencies offer incentives such as tax credits, grants, and exclusive marketing rights for a certain period of time. These measures help offset the higher costs and lower profit margins associated with developing and producing orphan drugs, ultimately benefiting patients with rare diseases who often have few or no treatment options available to them.
A rare disease, also known as an orphan disease, is a health condition that affects fewer than 200,000 people in the United States or fewer than 1 in 2,000 people in Europe. There are over 7,000 rare diseases identified, and many of them are severe, chronic, and often life-threatening. The causes of rare diseases can be genetic, infectious, environmental, or degenerative. Due to their rarity, research on rare diseases is often underfunded, and treatments may not be available or well-studied. Additionally, the diagnosis of rare diseases can be challenging due to a lack of awareness and understanding among healthcare professionals.
Deafness is a hearing loss that is so severe that it results in significant difficulty in understanding or comprehending speech, even when using hearing aids. It can be congenital (present at birth) or acquired later in life due to various causes such as disease, injury, infection, exposure to loud noises, or aging. Deafness can range from mild to profound and may affect one ear (unilateral) or both ears (bilateral). In some cases, deafness may be accompanied by tinnitus, which is the perception of ringing or other sounds in the ears.
Deaf individuals often use American Sign Language (ASL) or other forms of sign language to communicate. Some people with less severe hearing loss may benefit from hearing aids, cochlear implants, or other assistive listening devices. Deafness can have significant social, educational, and vocational implications, and early intervention and appropriate support services are critical for optimal development and outcomes.