title: β-Thalassemia in Abu Dhabi: consanguinity and tribal stratification are major factors explaining the high prevalence of the disease.
abstract: Tribalism and consanguineous marriages are common in parts of the world with a high prevalence of the β-thalassemia (β-thal) mutations, and increase the risks of homozygosity for this and other recessive disorders. We explored the frequency of β-thal genes and β-thal carriers in 5672 subjects screened before marriage, of whom 2262 were couples. The mean coefficient of inbreeding (F) in the population was estimated from self-reported relationships to prospective spouses in 383 subjects. Overall frequency of β-thal mutations and β-thal carriers in the population were 1.16 and 2.3%, respectively. Among the 14 largest tribes, β-thal carrier frequencies varied from 0 to 13.6%. The estimated F in the population was 0.022. The expected number of couples needed to be screened to detect one couple who were both β-thal carriers in the non inbreeding (F = 0) and inbreeding (F = 0.022) population was 1858 and 646, respectively. However, among 2262 couples, 10 were both β-thal carriers, i.e., 1 in 226 couples, significantly (p = 0.02) more than expected by taking only inbreeding into account. Although β-thal mutations are relatively rare, the burden of β-thal disease is increased eight-fold by tribalism and consanguinity.
authors.affiliation: Department of Medicine, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates. s.denic@uaeu.ac.ae
authors.forename: Srdjan
authors.initials: S
authors.lastname: Denic
authors.forename: Bashir
authors.initials: B
authors.lastname: Aden
authors.forename: Nico
authors.initials: N
authors.lastname: Nagelkerke
authors.forename: Awad Al
authors.initials: AA
authors.lastname: Essa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003241:Consanguinity; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D015995:Prevalence; D014479:United Arab Emirates / Q000453:epidemiology; D055815:Young Adult; D017086:beta-Thalassemia / Q000453:epidemiology* / Q000235:genetics*