CYSTIC-FIBROSIS IN LEBANON - DISTRIBUTION OF CFTR MUTATIONS AMONG ARAB COMMUNITIES

Cystic fibrosis (CF) is thought to be rare among the Arab populations from the Middle East and little data have been reported so far. We hav e studied a sample of 20 families living in Lebanon for several genera tions and who have at least one child with CE These families are mainl y from the Maronite, Creek Catholic, Creek Orthodox, Shiite or Sunnite groups. We found a 50% rate of consanguineous marriage, independent o f the community of origin. The distribution of CF genotypes was determ ined through the screening of all exons of the CFTR (cystic fibrosis t ransmembrane conductance regulator) gene by the technique of denaturin g gradient gel electrophoresis combined with asymmetric amplification DNA sequencing. A total of ten different mutations accounting for 87.5 % of 32 unrelated CF alleles was identified, including two novel putat ive mutations (E672del and IVS21-28G-->A). Three mutations, Delta F508 (37.5%), W12X2X (15.6%), and N1303K (9.4%) accounted for 62.5% of CF alleles. Interestingly, in the Maronite group, 66.7% of the Delta F508 chromosomes were found to be associated with allele 7 of the IVS8(T)t ract, contrasting with the absolute linkage disequilibrium between Eur opean Delta F508 chromosomes and allele 9. During this study, two prev iously undescribed polymorphisms (IVS14a + 17del5 and 2691T/C) were al so identified.