Polymorphic DNA haplotypes and delta F508 deletion in 212 Italian CF families.

Haplotype data based on the DNA markers closely linked to the cystic fibrosis (CF) gene have been used to correlate the presence of the 3 bp specific deletion (delta F508) in 424 CF chromosomes from 212 Italian CF families. The distribution and the frequency of the F508 deletion on CF chromosomes in our sample suggests the presence of at least a second mutation in the same ancestral haplotype.