IERG Abstracrt Book.indd - LV Prasad Eye Institute

52 Oral PresentationResults: Our data suggest that defects in TYR cause albinism in 57% (35/61) of the cases.Functional assays with the missense mutations proved that none of mutants are enzymaticallyactive and are retained in the endoplasmic reticulum (ER). Screening of the remaining cases(43%) revealed OCA2 to be the second common locus followed by SLC45A2. Evaluation ofSNPs in TYR, OCA2 and SLC45A2 as markers suggested definitive bias for some of the SNPstowards specific populations.Conclusions: Our investigation suggests that >50% of OCA in India belong to OCA1 category,followed by OCA2 and OCA4. ER retention is the major cause of lack of TYR activity in OCA1patients. Information on allelic distribution of SNPs would be important for cosegregationanalysis of candidate genes in OCA families.IPT 035Spectrum of Candidate Genes Mutation Associated with Indian FamilialOculocutaneous Albinism PatientsPeriasamy Sundaresan, 1 K. Renugadevi, 1 Asim Kumar Sil, 3 Perumalsamy Vijayalakshmi 21Department of Genetics, Dr.G.Venkataswamy Eye Research Institute, Aravind Medical ResearchFoundation, Aravind Eye Hospital, Madurai, Tamil Nadu, India. 2 Paediatric Clinic, Aravind EyeCare System, Aravind Eye Hospital, Madurai, Tamil Nadu, India, 3 Vivekananda Mission Asram,West Bengal, India.Purpose: Albinism is a group of genetic disorder, showing a broad phenotypic spectrum. Thephenotype ranges from complete lack of pigmentation in the skin, hair and iris-OculocutaneousAlbinism (OCA) or lack of pigmentation in the iris alone-Ocular Albinism (OA). The phenotypicranges of OCA and OA are depends on the candidate genes. Purpose of this study is to screenfor mutations in all the known candidate genes of OCA and OA1 to identify the mutation inIndian patients showing the positive history of albinism.Methods: Thirty six familial albinism patients from 23 genetically unrelated families werediagnosed by the standard methods of ophthalmologic views and investigated for the moleculargenetic analysis of four classic OCA genes – TYR, P (OCA2), TYRP1, SLC45A2 (MATP) and OA1gene – GPR143. The genomic DNA of 36 samples were subjected for bidirectional sequenceanalysis.Results: Three missense mutations R239W, R299H, G419R and one termination R278X wereidentified in TYR gene. One novel mutation G485R was identified in P gene. Along with thesemutations one novel SNP was identified in both, TYR and P genes and a few reported SNPswere identified in TYR, TYRP1, MATP and GPR143 genes.Conclusions: Despite the sequence analysis performed to all the five candidate genes, onlyfour probands among 23 had (17.39%) mutations in TYR gene and two probands (8.69%) hada novel mutation in P gene. Our study reports will contribute to the development of mutationdetection and early genetic counseling to the South Indian population.