HAPLOTYPE IDENTITY BETWEEN INDIVIDUALS WHO SHARE A CFTR MUTATION ALLELE IDENTICAL BY DESCENT - DEMONSTRATION OF THE USEFULNESS OF THE HAPLOTYPE-SHARING CONCEPT FOR GENE-MAPPING IN REAL POPULATIONS

Cystic fibrosis (CF) patients with the A455E mutation, in both the Fre nch Canadian and the Dutch population, share a common haplotype over d istances of up to 25 cM. French Canadian patients with the 621+1G-->T mutation share a common haplotype of more than 14 cM. In contrast, hap lotypes containing the Delta F508 mutation show haplotype identity ove r a much shorter genomic distance within and between populations, prob ably because of the multiple introduction of this most common mutation . Haplotype analysis for specific mutations in CF or in other recessiv e diseases can be used as a model for studying the occurrence of genet ic drift conditional on gene frequencies. Moreover, from our results, it can be inferred that analysis of shared haplotypes is a suitable me thod for genetic mapping in general.