Occurrence of the - -(SEA), - -(THAI) and - -(FIL) α-Thalassemia-1 Carriers from a 7-Year Study at Ramathibodi Hospital, Bangkok, Thailand.

α-Thalassemia (α-thal) is one of the most common genetic diseases in Thailand. Homozygosity of α-thal-1 (- -/- -) and compound heterozygosity of α-thal-1/α-thal-2 (- -/-α) leads to Hb Bart's (γ4) hydrops fetalis and Hb H (β4) disease, respectively. In order to better control and provide prevention of α-thal disease, the prevalence of α-thal-1 carriers and the types of genotypes in the Thai population should be known. A 7-year retrospective study, employing multiplex gap-polymerase chain reaction (gap-PCR) of 31,632 blood samples from Ramathibodi Hospital, Mahidol University, Bangkok, revealed an α-thal-1 carrier rate of 14.40% with the - -(SEA) (NG_000006.1: g.26264_45564del19301), - -(THAI) (NG_000006.1: g.10664_44164del33501) and - -(FIL) (NG_000006.1: g.11684_43534del31851) genotypes, constituting frequencies of 14.21, 0.18 and 0.01%, respectively. Although the - -(FIL) genotype is rare in the Thailand, its detection should be included in future α-thal screening programs.