MORBIDITY, BETA(S) HAPLOTYPE AND ALPHA-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 beta(S) chromosomes (from 39 SS, 11 AS, 2 S beta -thalassemia [S beta-thal] and I SD individuals) were determined using an allele-specific oligonucleotide (ASO) hybridization technique, whi le the alpha-globin gene status of 27 SS and 33 AS individuals, i.e. 1 20 chromosomes, was determined with a combination of polymerase chain reaction and ASO techniques. A vasoocclusive crisis was the most commo n (60.0%) cause of hospitalization, followed by infections (20%). Hosp ital admissions were most common during the hottest month of the year (July). Few complications of the disease were seen among patients on f ollow-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 hap lotype 19 was found in 12.0% and Bantu haplotype 20 in 6.5%. Hb F in t he haplotype 31 homozygotes and heterozygotes ranged from 11.4 to 35.1 % (mean 22.5 +/- 5.2%). The frequency of alpha-thal determinants in th e study was 40.0%, the commonest being the -alpha(3.7)-kb deletion (27 .5%), the alpha 2 polyadenylation signal (AATAAA->AATAAG) mutation (10 .2%) and the IVS-I 5' end GAGGT- GAGG->GAGG pentanucleotide (5 nt) del etion (3.3%). SS patients with coexistent alpha-thal trait did not hav e severe recurrent infections and none had gallstones. The high freque ncies of the Saudi Arabia/India PS haplotype and a-thalassemia trait c ontribute to the mild nature of SS disease among Kuwaiti Arabs compara ble to that in eastern Saudi Arabia.