Genetics of mental retardation.

Aim of this review is to present the latest advances in the identification of the genetic determinants of intellectual deficiency. Mental retardation (MR) is often associated with other neurologic symptoms, metabolic disorders, or malformation syndromes. The purpose of the review is to subdivide the large field of MR into categories that may help professionals in making a diagnosis. Nonspecific MR can also segregate in families and the mapping and cloning of corresponding mutant genes will eventually advance our understanding of normal and abnormal brain functioning. Several genes responsible for nonspecific X-linked mental retardation have been identified in the last 12 to 24 months and are being intensively investigated. This will hopefully lead to new possibilities of either genetic or pharmacological therapy.