We used multiplex PCR followed by sequencing to screen for mutations in the 14 exons of theRPE65 gene in early-hildhood-onset autosomal recessive retinitis pigmentosa (arRP) and Leber’s congenital amaurosis (LCA) patients. The RPE65 protein is believed to play an important role in the metabolism of vitamin A in the visual cycle and mutations identified in the gene could have implications for vitamin A-based therapeutic intervention. We were able to identify a homozygous mutation (AAT → AAG) in exon 9 in an arRP patient and a heterozygous missense transversion (AAT → AAG) also in exon 9 of an LCA patient. We also identified a polymorphism in exon 10 (GAG → GAA) in an arRP as well as an LCA patient. Mutation screening would be greatly facilitated by multiplex PCR which could cut down costs, labour and time involved. The nucleotide changes observed in this study could bede novo. Though a larger study has been undertaken, from the preliminary results it appears that in India theRPE65 gene seems to be less involved in causation of LCA.

Effective counselling and management of retinoblastoma families using genetic information is presently practised in many parts of the world. We studied histopathological, chromosomal and molecular-genetic data of two retinoblastoma patients from India. The two patients, one with bilateral and the other with unilateral retinoblastoma, underwent complete ophthalmic examination, cytogenetic study, retinoblastoma gene (RB1) mutational analysis andRB1 promoter region methylation screening. In the bilateral retinoblastoma patient deletion of chromosome region 13q14 in peripheral blood lymphocytes and a hemizygous novel 8-bp deletion in exon 4 ofRB1 in tumour sample were observed. In the unilaterally affected patient CGA to TGA transition protein truncation mutations were observed in exons 8 and 14 ofRB1.