Preliminary study of haplotypes linked to the rare cystic fibrosis E1104X mutation

The analysis of some extra- and intragenic markers within or closely linked to the cystic fibrosis transmembrane regulator (CFTR) gene is useful as a molecular method in clinical linkage analysis. Indeed, knowing that the molecular basis of cystic fibrosis (CF) is highly heterogeneous in our population, the study of haplotype association with normal and CF chromosomes could be very helpful in cases where one or both mutations remain unidentified. In this study, we analysed with PCR-RFLP and capillary electrophoresis some extra (pJ3.11, KM19 and XV2C) and intragenic (IVS8CA, IVS17bTA and IVS17bCA) polymorphic markers in 50 normal and 10 Tunisian patients carrying the rare E1104X mutation in order to determine the haplotype associated with this mutation. For the extragenic markers, 8 haplotypes were identified. The most frequent of them are the 221 and 112 accounting for 80% of total haplotypes. For the intragenic markers, five haplotypes were present on the E1104X chromosomes. One of them 16-31-13 accounted for 50%. To our knowledge, this is the first work to be interested to the haplotypes linked to the E1104X mutation. This preliminary study of haplotypes could be a helpful method to determine the molecular lesions responsible of this pathology.