Consanguinity and familial mental retardation.

Studies made in a group of patients with mental retardation showed that there was a high degree of parental consanguinity of the order of 30.3%. Index cases with parental consanguinity showed a relatively higher prevalence where more than one sib was affected. Cases with metabolic defects were also more common among cases with parental consanguinity. There is a need for studies in the general population in order to understand the biological significance of consanguinity.