Annals of Tropical Paediatrics (1999) 19, 69±73 Geographic distribution of cystic ®brosis transmembrane regulator gene mutations in Saudi Arabia H. BANJAR, M. KAMBOURIS *,² , B. F. MEYER * , A. AL-MEHAIDIB ** & I. MOGARRI Departments of Pediatrics, * Biological and Medical Research and ** Pediatric Gastroenterology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia and ² Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA (Accepted 29 June 1998) Summary A descriptive study was undertaken to characterize the cystic ®brosis transmembrane regulator gene mutations (CFTR) in the Saudi Arabian cystic ®brosis (CF) population in relation to clinical presentation and demographic and ethnic origin. During the period October 1992 to September 1997, 70 patients from 46 families were diagnosed as having CF, based on a typical clinical picture and sweat chloride levels . 60 mmol/l and were screened for CFTR mutations. Twelve mutations were identi®ed in 34 families, which constitutes 70% of the CF alleles in the study group. Pancreatic insuf®ciency (PI) was found in the following mutations: 1548delG in exon 10 (15%) which occurred mainly in native Saudi patients in the central province; 3120 1 1G ® A in intron 16 (10%) and H139L in exon 4 (7%), found mainly in native Saudis from the eastern province; D 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 1 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%) with pancreatic suf®ciency and minimal pulmonary disease. The clinical picture did not differ signi®cantly between patients of different ethnic origins with the same CFTR mutation. Introduction Cystic ®brosis is an inherited disease of the exocrine glands, whose clinical symptoms may include pulmonary disease, pancreatic ex- ocrine insuf®ciency, male infertility, meconium ileus and an increase in the con- centration of sweat electrolytes, which may lead to dehydration and metabolic alkalosis. It is the commonest autosomal recessive disease in Caucasians with an incidence of 1:2000 but is rare amongst Arabs and the populations of the Far East. Since the cloning of the CFTR gene in 1989, more than 750 new mutations have been reported to the CF consortium. In Saudi Arabia, 1 in 4243 children have been reported to suffer from CF, 1±3 but reports on CFTR mutations in this population have been scarce. 4±7 Six new CFTR mutations not found in any other population have been described as causing CF in Saudis. 7 D F508, which causes CF in 65±85% of the Caucasian popu- lation, 8±10 was found to be less frequent in the Saudi population. 4,5,7 Reprint requests to: Dr Hanaa Banjar, Department of Pediatrics, PO Box 3354, Riyadh 11211, Saudi Arabia. Fax: 1 966 1 442 7784. 0272-4936/99/010069-05 $9.00 Ó 1999 The Liverpool School of Tropical Medicine Carfax Publishing Ltd