CYSTIC-FIBROSIS IN THE BRAZILIAN POPULATION - DF508 MUTATION AND KM-19 XV-2C HAPLOTYPE DISTRIBUTION/

We have used PCR amplification of DNA obtained from Guthrie cards to i dentify the DF508 mutation and correlate it with the allele frequencie s at two polymorphic loci (XV-2C and KM-19) closely linked to the cyst ic fibrosis gene. The DNA came from 193 white Brazilian families affec ted by cystic fibrosis and living in five different states of Brazil. The distribution of the haplotypes derived from the DF508 and non-DF50 8 XV-2C/KM-19 genotypes indicates that 88% of the DF508 alleles are li nked to haplotype B and suggests that high heterogeneity exists among the non-DF508 cystic fibrosis alleles occurring in different states. O ur data can be used to compare linkage disequilibrium between Brazilia ns and other heterogeneous populations where the DF508 mutation freque ncy is low and where many different rare mutations account for the rem aining recessive cystic fibrosis alleles.