Retinitis pigmentosa genes implicated in South Asian populations: a systematic review

Retinitis pigmentosais one of the most prevalent causes of inherited retinal dystrophies worldwide. The widespread custom of consanguineous marriages in South Asian countries puts the population at risk for autosomal recessive disorders including retinitis pigmentosa. This systematic review was done between May and December 2015.A comprehensive literature search was carried out using MEDLINE and CINAHL databases and all relevant articles on causative mutations for non-syndromic Retinitis pigmentosa from 1999 till 2015 were included. Overall, 41 articles were identified involving 66 families; 28(68%)from Pakistan, 12(29%) from India and 1(2.4%) from Bangladesh. No data was available from the rest of countries in the region. Autosomal recessive was the most common pattern of inheritance and out of the known 60 genes thought to be involved in the pathogenesis of non-syndromic Retinitis pigmentosa, 32(53%) were identified in South Asia. Although significant progress has been made in this regard, there are many more loci that are yet to be identified. Our study found that significant gaps in knowledge exist due to lack of reported literature from countries other than Pakistan and India and the absence of cost-effective screening programmes in place.