Molecular genotyping and frequencies of A1, A2, B, O1 and O2 alleles of the ABO blood group system in a Kuwaiti population

Abstract

Expression of the highly polymorphic ABO gene cluster is commonly investigated for blood transfusion and analysis, but little information is available for Middle Eastern populations. This study determined the major ABO allele frequency in a Kuwaiti Arab cohort using a multiplex PCR-RFLP technique; 355 unrelated blood donors of phenotype A1 (46), A2 (31), A1B (6), A2B (4), B (97) and O (171) were genotyped. DNA fragments of 252 (251 for O1) and 843 (842 for A2) bp spanning the two major exons, 6 and 7, of the ABO gene were amplified and digested with HpaII and KpnI. Thirteen different genotypes could be identified when combining the A1, A2, B, O1 and O2 alleles from the digestion patterns: 1 A1 A1 (0.28%), 6 A1 A2 (1.69%), 38 A1 O1 (10.71%), 1 A1 O2 (0.28%), 1 A2 A2 (0.28%), 30 A2 O1 (8.45%), 6 A1 B (1.69%), 4 A2 B (1.13%), 12 BB (3.38%), 79 BO1 (22.25%), 6 BO2 (1.69%), 167 O1 O1 (47.04%) and 4 O1 O2 (1.13%). Two of the combinations (A2 O2, O2 O2) were not found. All genotypes determined were consistent with the serotypes. The frequencies of the five alleles in the Kuwaiti sample population were ABO*A1 = 0.0746, ABO*A2 = 0.0592, ABO*B = 0.1676, ABO*O1 = 0.6831 and ABO*O2 = 0.0155. These results are discussed with reference to gene frequencies reported for other ethnic groups.