Frequency of the cystic fibrosis 3199del6 mutation in individuals heterozygous for I148T.

Abstract

To determine the carrier frequency of the 3199del6 cystic fibrosis (CF) mutation in individuals heterozygous for I148T in a large-scale CF testing population. DNA samples from 439 consecutive I148T-heterozygous individuals were screened for the 3199del6 mutation using a laboratory-developed test. Genotyping revealed four samples heterozygous for the 3199del6 mutation (0.9%). The four samples positive for 3199del6 had an IVS 8 genotype of 7T/9T. The 3199del6 mutation was not observed after genotyping of 348 random, anonymous samples. The 3199del6 mutation occurs in 0.9% of individuals positive for the I148T mutation and <0.07% of chromosomes that are wild type for the ACMG panel mutations.