Allelic variations in the genes coding for human platelet antigens in four population groups in Borneo

Human platelet antigens (HPAs) are clinically significant markers in immune-mediated disorders. Comprehensive understanding of HPA genetic profiles at population level is essential for the prevention and management of these medical conditions. Such data for HPA allele frequencies have been collected for many ethnic groups in Peninsular Malaysia, but none from Sabah and Sarawak of Borneo. This study aims to determine the frequencies of HPA alleles in Bajau, Kadazan-Dusun, Murut and Melanau populations of Borneo.

Seven HPA loci (HPA-1 to -6 and -15) were genotyped using the polymerase chain reaction assay with sequence specific primers for 457 DNA samples representing four Borneo indigenous groups.

Significant departures from Hardy-Weinberg equilibrium (HWE) were observed for HPA-3 in Bajau, Kadazan-Dusun, Murut and Melanau groups and for HPA-15 in Bajau and Murut. High frequencies of HPA-1a, -2a, -4a, -5a, and -6a alleles were observed across all four populations. Exact tests showed significant differentiation between Borneo and Peninsular Malaysia populations, particularly for HPA-3 and -15. Principal component (PCA) analysis showed that the Borneo indigenous groups clustered closely with other Austronesian populations, consistent with the idea that they share genetic ancestry.

Observed HPA allele frequency spectra are uniquely distributed in Bajau, Kadazan-Dusun, Murut and Melanau population groups. The HPA population datasets generated from this study can be used as guidelines for health policy decision making and as reference sources for studying diseases associated with HPAs.