Genetic Studies in Intellectual Disability and Behavioral Impairment.

 Intellectual Disability (ID, also known as mental retardation) is a debilitating neurodevelopmental disorder affecting nearly 1% of the general population worldwide. Occurrence of behavioral disorders in individuals with ID is four times higher than that in the general population. An increasing number of studies seek to find a common pathway to elucidate brain structure/function and its contribution to behavior. This article deals with different behavioral disorders reported in individuals with syndromic and non-syndromic ID and possible candidate genes, most of which are involved in synaptic formation and function. Many ID cases with behavior impairments were referred to genetic centers to identify genetic causes; Therefore, the authors gathered data from their own studies along with similar published reports, to provide a review on genes involved in brain development and cognition. In this study, we argued how defects in genes with diverse functional role may contribute to  behavior impairments and a brain malfunction.  Evidences from individual with cognitive impairment as well as murine and drosophila animal models have been used to show  behavioral consequences of functional deficits in genes speculated to play a role in cognition and learning.