Consanguineous marriage is an intra­familial relationship between two people who share a common ancestor. This type of practice is occurring in most populations, with varying percentages among all marriages in South India. The present study was carried out to estimate the prevalence of consanguinity, degree of consanguinity and patterns of abnormalities among the population.We interviewed 2673 families to determine the effect of consanguinity on common hereditary disorders such as diabetics, hearing impairment and epilepsy in Sivagangai population, Tamil Nadu between November 2015 and March 2016. The degree of consanguinity between each female and her spouse and the degree of consanguinity between their parents were recorded. Of the selected families approached, the rate of consanguinity was 29.62% and coefficient of inbreeding in the current generation was significantly coinciding with the global rate of 29.2%. The degrees of consanguinity among the population were 2nd degree in 279 families, 3rd in 306 and 4th in 207. All marriages were occurred in first cousins and double first cousins. All reported diseases were more frequent in consanguineous marriages. In order to avoid such hereditary related health problems in India, it is imperative to create awareness regarding the adverse effects of endogamous marriages in regions with high prevalence.

Keywords: Endogamy; Degree of Consanguinity; Diabetes; Hearing Impairment and Epilepsy.