Cystic fibrosis in Greece: molecular diagnosis, haplotypes, prenatal diagnosis and carrier identification amongst high-risk individuals.

Cystic fibrosis (CF) mutation analysis on 437 CF patients, characterized 80 different mutations (20 so far specific to our population) accounting for 91% of CF genes and generating 103 different genotypes. Eight mutations were common [F508del (53.4%), 621+1G>T (5.7%), G542X (3.9%), N1303K (2.6%), 2789+5G>A (1.7%), 2183AA>G (1.4%), E822X (1.4%), R1158X (1%)], 12 showed frequencies between 0.5% and 1%, while the remaining (60) were very rare (1 to 3 alleles). Denaturing gradient gel electrophoresis (DGGE) screening of 12 exons (3, 4, 7, 10, 11, 13, 14b, 16, 17b 20 and 21) detected 85.5% of CF alleles. Haplotypes for eight diallelic and three microsatellite markers have been characterized for the common, a few rare and novel Greek mutations. Results of 165 prenatal diagnoses (including 49 due to bowel hyperechogenicity), testing a total of 41 different parental genotypes, are reported. One hundred and sixteen prenatal tests resulted in 22 affected, 59 heterozygous, 34 normal fetuses and one incomplete diagnosis. Of the 49 echogenic bowel fetuses, 3 were heterozygotes. Carrier screening was initiated, with emphasis on individuals and couples in high-risk groups - with a family history of CF, one partner with CF, and couples with male infertility seeking in vitro fertilization (IVF). Mutation analysis on 672 individuals (120 couples, 91 unaffected CF siblings, 283 CF family relatives and 58 general population subjects), identified a total of 176 heterozygotes and 7 couples where both partners were CF heterozygotes. Prenatal diagnosis was performed in 4 cases and 3 were counseled on the availability of a prenatal test.

CFTR gene mutations--including three novel nucleotide substitutions--and haplotype background in patients with asthma, disseminated bronchiectasis and chronic obstructive pulmonary disease.

In order to investigate the incidence of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations and unclassified variants in chronic pulmonary disease in children and adults, we studied 20 patients with asthma, 19 with disseminated bronchiectasis (DB) of unknown aetiology, and 12 patients with chronic obstructive pulmonary disease (COPD), and compared the results to 52 subjects from the general Greek population. Analysis of the whole coding region of the CFTR gene and its flanking intronic regions revealed that the proportion of CFTR mutations was 45% in asthma (P<0.05), 26.3% in DB (P>0.05), 16.7% in COPD (P>0.05), compared to 15.4% in the general population. Seventeen different molecular defects involved in disease predisposition were identified in 16 patients. Three potentially disease-causing mutations, T388 M, M1R and V11I, are novel, found so far only in three asthma patients. The hyperactive M470 allele was found more frequently in COPD patients (frequency 70.8%, P<0.01) than in the controls. The study of the TGmTnM470 V polyvariant CFTR allele revealed the presence of CFTR function-modulating haplotypes TG13/T5/M470, TG11/T5/M470, TG12/T5/V470 and TG12/T7, combined with M470 or V470, in six asthma patients, four DB patients (P<0.01), and two COPD patients (P<0.05). These results confirm the involvement of the CFTR gene in asthma, DB and possibly in COPD.