Hemoglobinopathy carrier prevalence in the United Arab Emirates: first analysis of the Dubai Health Authority premarital screening program results.

The aim of this study was to determine the prevalence of hemoglobinopathy carriers in United Arab Emirates (UAE) nationals subjected to mandatory premarital screening in Dubai over a 4-year period. Data from UAE nationals who underwent premarital screening by the Dubai Health Authority between January 2007 and December 2010 were collected and analyzed. Premarital screening in Dubai is based on complete blood counts (CBC) and hemoglobin (Hb) high performance liquid chromatography (HPLC). Among the 6,420 UAE nationals screened, 8.5% (n = 545) were suspected to be carriers. The following carrier frequencies were observed: β-thalassemia (β-thal), 4.56% (n = 293); Hb S [β6(A3)Glu→Val, GAG>GTG; HBB: c.20A>T], 2.9% (n = 186); Hb D-Punjab [β121(GH4)Glu→Gln, GAA>CAA; HBB: c.364G>C], 0.78% (n = 50); Hb Lepore (δβ hybrid gene) with an undetermined molecular genotype, 0.17% (n = 11); Hb E [β26(B8)Glu→Lys, GAG>AAG; HBB: c.79G>A], 0.03% (n = 2); and hereditary persistence of fetal Hb (HPFH), 0.016% (n = 1). Hb E-Hb S and Hb E-β-thal also occurred at a rate of 0.016% (n = 1) each; and 0.87% (n = 56) subjects were suspected of carrying silent β-thal. The prevalence of β-thal trait was consistent with the prevalence published by others in the region. Silent β-thal is challenging for screening programs, and is expected to arise in populations with a high prevalence of β-thal carriers. The prevalence of Hb S trait observed in this study was lower than that in other reports for the region. New cases of β-thal major (β-TM) still arise because many fertile couples got married before the screening programs were implemented, and pregnancy termination is not widely practiced in the UAE due to religious restraints. Moreover, some couples choose not to have prenatal diagnosis (PND) or pre implantation genetic diagnosis (PGD), even if they are aware of their risk status. The prevalence of β-thal trait in the UAE is high. This justifies efforts to control the disease by holding regular community awareness and screening programs, performing premarital screening and genetic counseling, and making PND and PGD available to couples who request it.