Defining a Mutational Panel and Predicting the Prevalence of Cystic Fibrosis in Oman

Objectives: Cystic fibrosis transmembrane conductance regulator (CFTR) mutations form distinct mutational panels in different populations and subgroups. The frequency of cystic fibrosis (CF) mutations and prevalence are unknown in Oman. This study aimed to elucidate the mutational panel and prevalence of CF for the North Al Batinah (NAB) region in Oman and to estimate the national prevalence of CF based on the carrier screening of unrelated volunteers. Methods: The study included retrospective and prospective analyses of CF cases in the NAB region for 1998–2012. Genetic analysis of disease-causing mutations was conducted by screening of the entire coding sequence and exon-intron borders. The obtained mutational panel was used for the carrier screening of 408 alleles of unrelated and unaffected Omani individuals. Results: S549R and F508del were the major mutations, accounting for 89% of mutations in the patient population. Two private mutations, c.1733-1734delTA and c.1175T>G, were identified in the patient cohort. Two carriers, one for F508del and another for S549R, were identified by screening of the volunteer cohort, resulting in a predicted prevalence for Oman of 1 in 8,264. The estimated carrier frequency of CF in Oman was 1 in 94. The carrier frequency in the NAB region was 3.9 times higher.Conclusion: The mutational panel for the NAB region and the high proportion of S549R mutations emphasises the need for specific screening for CF in Oman. The different distribution of allele frequencies suggests a spatial clustering of CF in the NAB region