REGIONAL DISTRIBUTION OF CYSTIC FIBROSIS-LINKED DNA HAPLOTYPES IN BRAZIL - MULTICENTER STUDY

The restriction fragment length polymorphism (RFLP) haplotypes of cyst ic fibrosis (CF) alleles vary between populations. To determine the di stribution of two RFLPs (XV-2C and KM-19) that are tightly linked to t he CF locus, we analyzed a white sample from five different states of Brazil. The haplotypes of 314 CF- and 237 non-CF-bearing chromosomes w ere uniformly distributed over the five states. The XV-2C allele and h aplotype frequencies and the degree of linkage disequilibrium were det ermined. These were similar to values previously reported in southern European countries but different from results reported for northern an d central Europe and North America. In contrast, although KM-19 allele frequencies differed between Brazilian states and European and North American countries, these frequencies were similar to values reported in black Americans. A significant proportion of Brazilian CF-bearing c hromosomes had less common haplotypes, suggesting a heterogeneous dist ribution of CF gene mutations among Brazilians. Further studies are ne eded to identify the mutations affecting the Brazilian CF patients wit h various haplotypes.