Two distinct alu-mediated deletions of the human ABO-secretor (FUT2) locus in Samoan and Bangladeshi populations

Abstract

The human secretor α(1,2) fucosyltransferase encoded by the FUT2 determines the production of ABO(H) antigens in secretions. Recent studies demonstrated the presence of several nonfunctional alleles in the FUT2. During the analysis for inactivating mutations at the FUT2 locus from 24 Samoan and 47 Bangladeshi individuals, we found two distinct Alu‐mediated deletions of FUT2. The FUT2 deletion in a Bangladeshi population was identical with that found in Indian individuals with the Bombay phenotype (sedel), but not associated with the null allele (T725G) of the H gene (FUT1). The FUT2 deletion in Samoans is a novel null allele (sedel2). The junction region of sedel2 was successfully amplified using the same primers for the sedel amplification. DNA sequencing of the junction region of the sedel2 indicated that there was a 32‐bp sequence identity between DNA sequences surrounding the 5′ and 3′ breakpoints. The size of the deletion of the sedel2 was 9.3 kb, including the full coding region of FUT2. The frequency of the sedel in a Bangladeshi population was 0.074, and that of the sedel2 in a Samoan population was 0.104. Hum Mutat 16:274, 2000. © 2000 Wiley‐Liss, Inc.

Polymorphism of the human ABO‐Secretor locus (FUT2) in four populations in Asia: indication of distinct Asian subpopulations

“…The se%#) allele, which contains a nonsense mutation G428A and a further six base substitutions compared to the reference allele reported by Kelly et al (1995) (see Fig. 1), is predominant in Africans and Europeans Liu et al 1998) (Koda et al 1996) and some, but not all, individuals homozygous for the se$&( ,$)& showed the Le(ajbj) phenotype on red cells, Yu et al (1995) and (Henry et al 1996 b, c ;Chang et al 1999 ;Peng et al 1999 ;Pang et al 2000). The Se%!…”

“…Another set of primers was used for the amplification of the two deleted alleles, se del and se del# , as previously described Pang et al 2000). The three recombinants were identified by electrophoresing the PCR products on a 1n0% agarose gel and then staining with ethidium bromide.…”

“…The se del was originally identified in Indian individuals with the classical Bombay phenotype (Koda et al 1997 ;Fernandez-Mateos et al 1998) and also recently found in a Bangladeshi population with a high frequency (0n074) (Pang et al 2000). The se del# has been found in Samoans (Pang et al 2000).…”

“…In addition, we have reported three recombinant FUT2 alleles as nonfunctional alleles : one was the fusion gene (se fus ), consisting of the 5h region of a pseudogene of FUT2 (Sec1) and the 3h region of the FUT2 in Japanese individuals (Koda et al 1996 ;Liu et al 1999), while the other two were distinct and included complete deletion of the FUT2 (se del and se del# ) generated by Alu-Alu recombination (Koda et al 1997Pang et al 2000). The se del was originally identified in Indian individuals with the classical Bombay phenotype (Koda et al 1997 ;Fernandez-Mateos et al 1998) and also recently found in a Bangladeshi population with a high frequency (0n074) (Pang et al 2000). The se del# has been found in Samoans (Pang et al 2000).…”

Patterns of human genetic variation inferred from comparative analysis of allelic mutations in blood group antigen genes

“…Other evidence suggests that four alleles of FUT2, are definitely products of recombination (not depicted in Fig. 5): two result in gene deletions and involve ALU sequences within 5 0 and 3 0 regions of FUT2, and two others, se6 and se8, are hybrids that result from recombination, possibly gene conversion, between two different homologous regions of FUT2 and the pseudogene [Koda et al, 1996Pang et al, 2000;Soejima et al, 2008]. No evidence for recombinant alleles involving FUT1 had been documented so far.…”