Genetics of cognitive disorders

Disorders of cognition impair mental processes mediating awareness, perception, reasoning, or judgment, and consequently interfere with thought. Although interindividual differences in human cognition are easily observed, little is known about the genetic factors underlying such phenotypic variation, or the relationship of such variation to disease. Global measures of intelligence, such as Spearman's “g”, are heritable and thus likely to engender new links between genes and cognition. However, the breadth of these measures may limit the extent to which mechanistic insights are obtained. Finding readily measurable and heritable components of disease (endophenotypes) represents one of the most promising avenues for a precise understanding of how individual genes come to modulate brain function. The high heritability of interindividual differences in brain morphology suggests that a more thorough understanding of disease-associated structural variation may clarify the relationship between individual genes and disorders of cognition. Identification and study of endophenotypes for autism and disorders of spoken and written language will facilitate a deeper understanding of how genetic variation comes to modulate the structure and function of particular neural systems and in turn contributes to specific cognitive deficits. Keywords: autism; behavior; brain structure; cognition; dyslexia; endophenotypes; g; language