Estimation of secretor status of ABO antigens by high-resolution melting analysis of rs601338 (428G > A)

Abstract

BackgroundFUT2 determines the secretor status of ABH antigens. Many lines of evidence suggest an association between secretor status and susceptibility to various clinical conditions. For this kind of study, large-scale genotyping of FUT2 is necessary. Because FUT2 has a pseudogene (SEC1) with high DNA sequence similarity and is rich in population-specific SNPs, we need to pay attention in designing the primers for genotyping FUT2. The se428 allele having a 428G > A nonsense SNP (W143X, rs601338) is the predominant non-secretor allele in Europeans, Latin Americans and Africans. On the other hand, se357,480,778del having the 778C > del frameshift SNP (P260Lfs*16, rs1799761) is almost exclusively found in Africans with frequencies of 1–4%.STUDY DESIGN AND METHODS: We developed high-resolution melting (HRM) analyses using short (69-bp for 428G > A, 65-bp for 778C > del) amplicons for genotyping two SNPs directly and validated the method by analyzing 95 Ghanaians whose FUT2 genotypes were previously determined. ResultsTwo sets of assays clearly discriminated three genotypes of 428G > A (G/G, G/A, A/A), and two genotypes of 778C > del (C/C, C/del). In addition, the results obtained for the 95 Ghanaians by HRM analysis were in full agreement with previous ones. ConclusionThe present HRM analysis reliably genotyped 428G > A. Thus, estimation of secretor status based on se428 using the present HRM analysis may be useful for large scale association studies of FUT2. In addition to 428G > A, genotyping of other causal polymorphisms for non-secretors with high frequency, as is the case with 778C > del for Africans, is desirable for more accurate estimation of the secretor status of the target populations.