Measurable biological (physiological, biochemical, and anatomical features), behavioral (psychometric pattern) or cognitive markers that are found more often in individuals with a disease than in the general population. Because many endophenotypes are present before the disease onset and in individuals with heritable risk for disease such as unaffected family members, they can be used to help diagnose and search for causative genes.

A late-appearing component of the event-related potential. P300 stands for a positive deflection in the event-related voltage potential at 300 millisecond poststimulus. Its amplitude increases with unpredictable, unlikely, or highly significant stimuli and thereby constitutes an index of mental activity. (From Campbell, Psychiatric Dictionary, 6th ed)

The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.

Chronic form of ichthyosis that is inherited as a sex-linked recessive trait carried on the X-chromosome and transmitted to the male offspring. It is characterized by severe scaling, especially on the extremities, and is associated with steroid sulfatase deficiency.

Study of mental processes and behavior of schizophrenics.

A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.

Persons or animals having at least one parent in common. (American College Dictionary, 3d ed)

Research into the cause, transmission, amelioration, elimination, or enhancement of inherited disorders and traits.

The electric response evoked in the CEREBRAL CORTEX by ACOUSTIC STIMULATION or stimulation of the AUDITORY PATHWAYS.

Methods of detecting genetic etiology in human traits. The basic premise of twin studies is that monozygotic twins, being formed by the division of a single fertilized ovum, carry identical genes, while dizygotic twins, being formed by the fertilization of two ova by two different spermatozoa, are genetically no more similar than two siblings born after separate pregnancies. (Last, J.M., A Dictionary of Epidemiology, 2d ed)

Disturbances in mental processes related to learning, thinking, reasoning, and judgment.

A major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.

A social group consisting of parents or parent substitutes and children.

A complex involuntary response to an unexpected strong stimulus usually auditory in nature.

Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.

The analysis of a sequence such as a region of a chromosome, a haplotype, a gene, or an allele for its involvement in controlling the phenotype of a specific trait, metabolic pathway, or disease.

The ability of the BRAIN to suppress neuronal responses to external sensory inputs, such as auditory and visual stimuli. Sensory filtering (or gating) allows humans to block out irrelevant, meaningless, or redundant stimuli.

The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.

The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.

Disorders affecting TWINS, one or both, at any age.

A disorder beginning in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual. (DSM-V)

An act performed without delay, reflection, voluntary direction or obvious control in response to a stimulus.

A major deviation from normal patterns of behavior.

A behavior disorder originating in childhood in which the essential features are signs of developmentally inappropriate inattention, impulsivity, and hyperactivity. Although most individuals have symptoms of both inattention and hyperactivity-impulsivity, one or the other pattern may be predominant. The disorder is more frequent in males than females. Onset is in childhood. Symptoms often attenuate during late adolescence although a minority experience the full complement of symptoms into mid-adulthood. (From DSM-V)

The different ways GENES and their ALLELES interact during the transmission of genetic traits that effect the outcome of GENE EXPRESSION.

The tendency to explore or investigate a novel environment. It is considered a motivation not clearly distinguishable from curiosity.

Marked depression appearing in the involution period and characterized by hallucinations, delusions, paranoia, and agitation.

A characteristic showing quantitative inheritance such as SKIN PIGMENTATION in humans. (From A Dictionary of Genetics, 4th ed)

A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.

An analysis comparing the allele frequencies of all available (or a whole GENOME representative set of) polymorphic markers in unrelated patients with a specific symptom or disease condition, and those of healthy controls to identify markers associated with a specific disease or condition.

Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.

Intellectual or mental process whereby an organism obtains knowledge.

Psychiatric illness or diseases manifested by breakdowns in the adaptational process expressed primarily as abnormalities of thought, feeling, and behavior producing either distress or impairment of function.

The health status of the family as a unit including the impact of the health of one member of the family on the family as a unit and on individual family members; also, the impact of family organization or disorganization on the health status of its members.