Morbidity, β^s haplotype and α-globin gene patterns among sickle cell anemia patients in Kuwait

Admission records of children with sickle cell anemia (SS), in the two main teaching hospitals in Kuwait, were reviewed for a 1-year period. The haplotypes of 92 ²s chromosomes (from 39 SS, 11 AS, 2 S²-thalassemia [S² -thal] and 1 SD individuals) were determined using an allele-specific oligonucleotide (ASO) hybridization technique, while the ±-globin gene status of 27 SS and 33 AS individuals, i.e. 120 chromosomes, was determined with a combination of polymerase chain reaction and ASO techniques. A vasoocclusive crisis was the most common (60.0%) cause of hospitalization, followed by infections (20%). Hospital admissions were most common during the hottest month of the year (July). Few complications of the disease were seen among patients on follow-up; however, splenomegaly was present in 24.0%, hepatomegaly in 15.2%, gallstones in 15.2% and aseptic necrosis of the femoral head in 6.1%. Haplotype 31 (Saudi Arabia/India) is the most frequent in this community, being present in 80.4% of the chromosomes tested; Benin haplotype 19 was found in 12.0% and Bantu haplotype 20 in 6.5%. Hb F in the haplotype 31 homozygotes and heterozygotes ranged from 11.4 to 35.1% (mean 22.5 ± 5.2%). The frequency of ±-thal determinants in the study was 40.0%, the commonest being the -±3-7-kb deletion (27.5%), the ±2 polyadenylation signal (AATAAA-> AATAAG) mutation (10.2%) and the IVS-I 5’ end GAGGT-GAGG-> GAGG pentanucleotide (5 nt) deletion (3.3%). SS patients with coexistent ±-thal trait did not have severe recurrent infections and none had gallstones. The high frequencies of the Saudi Arabia/India ²s haplotype and ±-thalassemia trait contribute to the mild nature of SS disease among Kuwaiti Arabs comparable to that in eastern Saudi Arabia. © 1996 S. Karger AG, Basel.