Hereditary Sensory and Autonomic Neuropathies: A group of inherited disorders characterized by degeneration of dorsal root and autonomic ganglion cells, and clinically by loss of sensation and autonomic dysfunction. There are five subtypes. Type I features autosomal dominant inheritance and distal sensory involvement. Type II is characterized by autosomal inheritance and distal and proximal sensory loss. Type III is DYSAUTONOMIA, FAMILIAL. Type IV features insensitivity to pain, heat intolerance, and mental deficiency. Type V is characterized by a selective loss of pain with intact light touch and vibratory sensation. (From Joynt, Clinical Neurology, 1995, Ch51, pp142-4)Serine C-Palmitoyltransferase: A key enzyme in SPHINGOLIPIDS biosynthesis, this enzyme catalyzes the pyridoxal-5'-phosphate-dependent condensation of L-SERINE and PALMITOYL COENZYME A to 3-dehydro-D-sphinganine. The enzyme consists of two different subunits.Self Mutilation: The act of injuring one's own body to the extent of cutting off or permanently destroying a limb or other essential part of a body.Diabetic Neuropathies: Peripheral, autonomic, and cranial nerve disorders that are associated with DIABETES MELLITUS. These conditions usually result from diabetic microvascular injury involving small blood vessels that supply nerves (VASA NERVORUM). Relatively common conditions which may be associated with diabetic neuropathy include third nerve palsy (see OCULOMOTOR NERVE DISEASES); MONONEUROPATHY; mononeuropathy multiplex; diabetic amyotrophy; a painful POLYNEUROPATHY; autonomic neuropathy; and thoracoabdominal neuropathy. (From Adams et al., Principles of Neurology, 6th ed, p1325)Autonomic Nervous System Diseases: Diseases of the parasympathetic or sympathetic divisions of the AUTONOMIC NERVOUS SYSTEM; which has components located in the CENTRAL NERVOUS SYSTEM and PERIPHERAL NERVOUS SYSTEM. Autonomic dysfunction may be associated with HYPOTHALAMIC DISEASES; BRAIN STEM disorders; SPINAL CORD DISEASES; and PERIPHERAL NERVOUS SYSTEM DISEASES. Manifestations include impairments of vegetative functions including the maintenance of BLOOD PRESSURE; HEART RATE; pupil function; SWEATING; REPRODUCTIVE AND URINARY PHYSIOLOGY; and DIGESTION.Charcot-Marie-Tooth Disease: A hereditary motor and sensory neuropathy transmitted most often as an autosomal dominant trait and characterized by progressive distal wasting and loss of reflexes in the muscles of the legs (and occasionally involving the arms). Onset is usually in the second to fourth decade of life. This condition has been divided into two subtypes, hereditary motor and sensory neuropathy (HMSN) types I and II. HMSN I is associated with abnormal nerve conduction velocities and nerve hypertrophy, features not seen in HMSN II. (Adams et al., Principles of Neurology, 6th ed, p1343)Hereditary Sensory and Motor Neuropathy: A group of slowly progressive inherited disorders affecting motor and sensory peripheral nerves. Subtypes include HMSNs I-VII. HMSN I and II both refer to CHARCOT-MARIE-TOOTH DISEASE. HMSN III refers to hypertrophic neuropathy of infancy. HMSN IV refers to REFSUM DISEASE. HMSN V refers to a condition marked by a hereditary motor and sensory neuropathy associated with spastic paraplegia (see SPASTIC PARAPLEGIA, HEREDITARY). HMSN VI refers to HMSN associated with an inherited optic atrophy (OPTIC ATROPHIES, HEREDITARY), and HMSN VII refers to HMSN associated with retinitis pigmentosa. (From Adams et al., Principles of Neurology, 6th ed, p1343)Information Centers: Facilities for collecting and organizing information. They may be specialized by subject field, type of source material, persons served, location, or type of services.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Rare Diseases: A large group of diseases which are characterized by a low prevalence in the population. They frequently are associated with problems in diagnosis and treatment.National Health Planning Information Center (U.S.): A center in the HEALTH RESOURCES ADMINISTRATION Division of Planning Methods and Technology which provides access to current information on health planning and resources development.Dysautonomia, Familial: An autosomal disorder of the peripheral and autonomic nervous systems limited to individuals of Ashkenazic Jewish descent. Clinical manifestations are present at birth and include diminished lacrimation, defective thermoregulation, orthostatic hypotension (HYPOTENSION, ORTHOSTATIC), fixed pupils, excessive SWEATING, loss of pain and temperature sensation, and absent reflexes. Pathologic features include reduced numbers of small diameter peripheral nerve fibers and autonomic ganglion neurons. (From Adams et al., Principles of Neurology, 6th ed, p1348; Nat Genet 1993;4(2):160-4)Kinetin: A furanyl adenine found in PLANTS and FUNGI. It has plant growth regulation effects.Primary Dysautonomias: Disorders of the AUTONOMIC NERVOUS SYSTEM occurring as a primary condition. Manifestations can involve any or all body systems but commonly affect the BLOOD PRESSURE and HEART RATE.Aesculus: A plant genus of the family HIPPOCASTANACEAE (or SAPINDACEAE by some) that contains antimicrobial protein 1 and escin. A. hippocastanum is used in folk medicine for treating chronic venous insufficiency.Pure Autonomic Failure: A degenerative disease of the AUTONOMIC NERVOUS SYSTEM that is characterized by idiopathic ORTHOSTATIC HYPOTENSION and a greatly reduced level of CATECHOLAMINES. No other neurological deficits are present.Cerebellar Ataxia: Incoordination of voluntary movements that occur as a manifestation of CEREBELLAR DISEASES. Characteristic features include a tendency for limb movements to overshoot or undershoot a target (dysmetria), a tremor that occurs during attempted movements (intention TREMOR), impaired force and rhythm of diadochokinesis (rapidly alternating movements), and GAIT ATAXIA. (From Adams et al., Principles of Neurology, 6th ed, p90)Spinocerebellar Degenerations: A heterogenous group of degenerative syndromes marked by progressive cerebellar dysfunction either in isolation or combined with other neurologic manifestations. Sporadic and inherited subtypes occur. Inheritance patterns include autosomal dominant, autosomal recessive, and X-linked.Sural Nerve: A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot.Sphingolipids: A class of membrane lipids that have a polar head and two nonpolar tails. They are composed of one molecule of the long-chain amino alcohol sphingosine (4-sphingenine) or one of its derivatives, one molecule of a long-chain acid, a polar head alcohol and sometimes phosphoric acid in diester linkage at the polar head group. (Lehninger et al, Principles of Biochemistry, 2nd ed)Nervous System Diseases: Diseases of the central and peripheral nervous system. This includes disorders of the brain, spinal cord, cranial nerves, peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscle.Peripheral Nervous System Diseases: Diseases of the peripheral nerves external to the brain and spinal cord, which includes diseases of the nerve roots, ganglia, plexi, autonomic nerves, sensory nerves, and motor nerves.Myelin Proteins: MYELIN-specific proteins that play a structural or regulatory role in the genesis and maintenance of the lamellar MYELIN SHEATH structure.Median Neuropathy: Disease involving the median nerve, from its origin at the BRACHIAL PLEXUS to its termination in the hand. Clinical features include weakness of wrist and finger flexion, forearm pronation, thenar abduction, and loss of sensation over the lateral palm, first three fingers, and radial half of the ring finger. Common sites of injury include the elbow, where the nerve passes through the two heads of the pronator teres muscle (pronator syndrome) and in the carpal tunnel (CARPAL TUNNEL SYNDROME).Cytoplasmic Dyneins: Dyneins that are responsible for intracellular transport, MITOSIS, cell polarization, and movement within the cell.Dyneins: A family of multisubunit cytoskeletal motor proteins that use the energy of ATP hydrolysis to power a variety of cellular functions. Dyneins fall into two major classes based upon structural and functional criteria.Microtubules: Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.Kinesin: A microtubule-associated mechanical adenosine triphosphatase, that uses the energy of ATP hydrolysis to move organelles along microtubules toward the plus end of the microtubule. The protein is found in squid axoplasm, optic lobes, and in bovine brain. Bovine kinesin is a heterotetramer composed of two heavy (120 kDa) and two light (62 kDa) chains. EC 3.6.1.-.Myosin Type V: A subclass of myosin involved in organelle transport and membrane targeting. It is abundantly found in nervous tissue and neurosecretory cells. The heavy chains of myosin V contain unusually long neck domains that are believed to aid in translocating molecules over large distances.Loa: A genus of parasitic nematodes found throughout the rain-forest areas of the Sudan and the basin of the Congo. L. loa inhabits the subcutaneous tissues, which it traverses freely.Molecular Motor Proteins: Proteins that are involved in or cause CELL MOVEMENT such as the rotary structures (flagellar motor) or the structures whose movement is directed along cytoskeletal filaments (MYOSIN; KINESIN; and DYNEIN motor families).Jews: An ethnic group with historical ties to the land of ISRAEL and the religion of JUDAISM.Canavan Disease: A rare neurodegenerative condition of infancy or childhood characterized by white matter vacuolization and demeylination that gives rise to a spongy appearance. Aspartoacylase deficiency leads to an accumulation of N-acetylaspartate in astrocytes. Inheritance may be autosomal recessive or the illness may occur sporadically. This illness occurs more frequently in individuals of Ashkenazic Jewish descent. The neonatal form features the onset of hypotonia and lethargy at birth, rapidly progressing to coma and death. The infantile form features developmental delay, DYSKINESIAS, hypotonia, spasticity, blindness, and megalencephaly. The juvenile form is characterized by ATAXIA; OPTIC ATROPHY; and DEMENTIA. (From Adams et al., Principles of Neurology, 6th ed, p944; Am J Med Genet 1988 Feb;29(2):463-71)Tay-Sachs Disease: An autosomal recessive neurodegenerative disorder characterized by the onset in infancy of an exaggerated startle response, followed by paralysis, dementia, and blindness. It is caused by mutation in the alpha subunit of the HEXOSAMINIDASE A resulting in lipid-laden ganglion cells. It is also known as the B variant (with increased HEXOSAMINIDASE B but absence of hexosaminidase A) and is strongly associated with Ashkenazic Jewish ancestry.beta-Hexosaminidase alpha Chain: The alpha subunit of hexosaminidase A. Mutations in the gene that encodes this protein can result in loss of hexosaminidase A activity and are linked to TAY-SACHS DISEASE.Hexosaminidase A: A mammalian beta-hexosaminidase isoform that is a heteromeric protein comprized of both hexosaminidase alpha and hexosaminidase beta subunits. Deficiency of hexosaminidase A due to mutations in the gene encoding the hexosaminidase alpha subunit is a case of TAY-SACHS DISEASE. Deficiency of hexosaminidase A and HEXOSAMINIDASE B due to mutations in the gene encoding the hexosaminidase beta subunit is a case of SANDHOFF DISEASE.Arthropathy, Neurogenic: Chronic progressive degeneration of the stress-bearing portion of a joint, with bizarre hypertrophic changes at the periphery. It is probably a complication of a variety of neurologic disorders, particularly TABES DORSALIS, involving loss of sensation, which leads to relaxation of supporting structures and chronic instability of the joint. (Dorland, 27th ed)Neurology: A medical specialty concerned with the study of the structures, functions, and diseases of the nervous system.Peroneal Nerve: The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot.Peripheral Nerves: The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.Neural Conduction: The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.Polyneuropathies: Diseases of multiple peripheral nerves simultaneously. Polyneuropathies usually are characterized by symmetrical, bilateral distal motor and sensory impairment with a graded increase in severity distally. The pathological processes affecting peripheral nerves include degeneration of the axon, myelin or both. The various forms of polyneuropathy are categorized by the type of nerve affected (e.g., sensory, motor, or autonomic), by the distribution of nerve injury (e.g., distal vs. proximal), by nerve component primarily affected (e.g., demyelinating vs. axonal), by etiology, or by pattern of inheritance.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Reflex, Babinski: A reflex found in normal infants consisting of dorsiflexion of the HALLUX and abduction of the other TOES in response to cutaneous stimulation of the plantar surface of the FOOT. In adults, it is used as a diagnostic criterion, and if present is a NEUROLOGIC MANIFESTATION of dysfunction in the CENTRAL NERVOUS SYSTEM.Diagnostic Errors: Incorrect diagnoses after clinical examination or technical diagnostic procedures.Speech: Communication through a system of conventional vocal symbols.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Speech Perception: The process whereby an utterance is decoded into a representation in terms of linguistic units (sequences of phonetic segments which combine to form lexical and grammatical morphemes).Cellulitis: An acute, diffuse, and suppurative inflammation of loose connective tissue, particularly the deep subcutaneous tissues, and sometimes muscle, which is most commonly seen as a result of infection of a wound, ulcer, or other skin lesions.Speech Disorders: Acquired or developmental conditions marked by an impaired ability to comprehend or generate spoken forms of language.