R659X mutation in the MLH1 gene in hereditary non-polyposis colorectal cancer(HNPCC) in an Indian extended family.

R659X mutation correlates with disease phenotype, and 655A>G locus is highly polymorphic. Our study suggested that R659X substitution was prime cause for the disease phenotype in this family. I219V substitution is a polymorphism having no association with the disease onset or segregation. The family members harbouring this mutation were advised to be under regular medical surveillance.