Comprehensive analysis of the molecular bases of OCA in Indians
© Ray et al; licensee BioMed Central Ltd. 2010
Published: 11 October 2010
OCA is a group of autosomal recessive disorders characterized by hypopigmentation and abnormalities related to ocular development. Mutations in genes regulating melanin-biosynthesis cause four classical types of OCA (OCA 1-4). The clinical spectrum of OCA often depends on the pigmentation threshold of a patient, highlighting the importance of ethnic- specific SNPs. We aimed to understand the molecular bases of OCA in India, where it is one of the four major causes of childhood blindness.
Materials and methods
Blood samples were collected from OCA patients and family members, mostly from eastern and southern India. Seven pigmentation related genes were screened for variations. Relevant non-synonymous changes in tyrosinase (TYR) were functionally validated. Eighteen SNPs from three OCA genes were genotyped in 552 normal individuals covering various ethnic groups of India.
Our investigation suggests that ~58% of OCA in India belong to OCA1 category. ER retention is the major cause of lack of TYR activity in OCA1 patients. Information on allelic distribution of SNPs is important for cosegregation analysis of candidate genes in affected families.
SNP analysis in Indian population groups was done as part of a larger study to capture genomic variation among Indians by the Indian Genome Variation Consortium.
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