In this study, 132 CF chromosomes were analyzed for 11 common mutations (Table 1). These mutations account for 80.1% of the CF alleles in patients from northern Greece. The DF508 has a frequency of 56.06%, while the second most frequent mutation is the 621+1 (G®T) with 12.12%.

The genotype frequencies among the 66 CF patients are shown in Table 1. The most frequent genotypes are the DF508/DF508, the DF508/unknown, and the DF508/621+1 (G®T). All the other genotypes show frequencies lower than 10%.

The distribution of the CF genotypes according to the patient's exact region of origin shows the following: the most frequent genotypes in the region of Macedonia are the DF508/DF508 and DF508/unknown with equal frequency (24.4%), followed by the DF508/621+1 (G®T) (15.5%). In the region of Thessaly the most frequent genotype is the DF508/DF508 (41.17%), followed by the DF508/621+1 (G®T) (23.3%) and DF508/unknown (17.64%).

The haplotypes for Xv-2c, KM.19, MET-D, MET-H and M470V DNA polymorphic markers, in non-CF chromosomes and CF chromosomes of patients carrying the 621+1 (G®T) mutation are given in Table 2. This analysis revealed that almost all of the 621+1 (G®T) chromosomes are associated with the H5 haplotype. On the other hand, the DF508 chromosomes are mainly in association with haplotype H3. It seems that the 621+1 (G®T) chromosomes found in northern Greece are associated with a haplotype that is not detected in DF508 or in the non-CF chromosomes.