Geographic distribution of cystic fibrosis transmembrane regulator gene mutations in Saudi Arabia

A descriptive study was undertaken to characterize the cystic fibrosis tran smembrane regulator gene mutations (CFTR) in the Saudi Arabian cystic fibro sis (CF) population in relation to clinical presentation and demographic an d ethnic origin. During the period October 1992 to September 1997, 70 patie nts from 46 families were diagnosed as having CF, based on a typical clinic al picture and sweat chloride levels >60 mmol/l and were screened for CFTR mutations. Twelve mutations were identified in 34 families, which constitut es 70% of the CF alleles in the study group. Pancreatic insufficiency (PI) was found in the following mutations: 1548delG in exon 10 (15%) which occur red mainly in native Saudi patients in the central province; 3120 + 1G-->A in intron 16 (10%) and H139L in exon 4 (7%), found mainly in native Saudis from the eastern province; Delta F508 mutation (13%) which occurred mainly in expatriates of Middle Eastern origin from different provinces; L117X in exon 19 (2%); G115X in exon 4 (2%); 711 + 1G-->A in intron 5 (2%); N 1303K in exon 21 (2%) and 425del42 in exon 4 (1%); I1234V in exon 19 (13%) with a predominance of nasal polyps and a variable degree of PI and lung disease; R553X in exon 11 (1%), with electrolyte imbalance; and S549R in 11 (2%) wi th pancreatic sufficiency and minimal pulmonary disease. The clinical pictu re did not differ significantly between patients of different ethnic origin s with the same CFTR mutation.