BRCA1, BRCA2 and CHEK2 (1100 del C) germline mutations in hereditary breast and ovarian cancer families in South India.

Cancer of the breast is the second most common cancer seen among Indian women. This study describes the use of DHPLC for mutation analysis for BRCA1, BRCA2 and CHEK2 (1100delC) in 22 patients with a family history of breast and/or ovarian cancer and early onset breast cancer (<35 years of age). Three of the 22 patients were found to have a non-sense mutation or a deletion, resulting in a premature stop codon, potentially leading to a truncated protein. Two of these were in BRCA1 (one was a novel 5 base deletion) and one in the BRCA2 gene. No patient was found in our series to have the CHEK2 (1100delC) mutation. DNA from a healthy blood donor and all but one of the 22 patients, demonstrated polymorphisms in BRCA1 and/or BRCA2 genes. This is the first study from South India, on BRCA1, BRCA2 & CHEK2 (1100 del C) mutations in patients with a family history of breast and/or ovarian cancer and early onset breast/ovarian cancer, using the sensitive DHPLC approach.

RPE65 gene: multiplex PCR and mutation screening in patients from India with retinal degenerative diseases.

We used multiplex PCR follwed by sequencing to screen for mutations in the 14 exons of the RPE65 gene in early-childhood-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 be de novo. Though a larger study has been undertaken, from the preliminary results it appears that in India the RPE65 gene seems to be less involved in causation of LCA.