Two prevalent h alleles in para-Bombay haplotypes among 250,000 Taiwanese.
Alpha(1,2)-fucosyltransferase catalyzes the transfer of fucose to the C-2 position of galactose on type II precursor substrate Gal beta1-4GlcNAc beta1-R. It plays an important biological role in the formation of H antigen, a precursor oligosaccharide for both A and B antigens on red blood cells. Aberration of alpha(1,2)-fucosyltransferase activity by gene mutations results in decreased synthesis of H antigen, leading to the para-Bombay phenotype. In this study, we collected about 250,000 blood samples in Taiwan during 5 yr and identified the subjects with para-Bombay phenotype. Then we analyzed the sequence of the alpha(1,2)-fucosyltransferase gene by direct sequencing and gene cloning methods, using the blood samples of 30 para-Bombay individuals and 30 control subjects who were randomly selected. The goals of this study were to search for new h alleles, to determine the h allele frequencies, and to test whether the sporadic theory is applicable in Taiwan. Six different h alleles (ha, 547-548 AG-del; hb, 880-881 TT-del; hc, R220C; hd, R220H; he, F174L; and hf, N327T) were observed. Two h alleles, he and hf, were newly discovered in Taiwan. The he allele has a nucleotide 522C>A point mutation, predicting the amino acid 174 substitution of Phe to Leu; the hf allele has missense mutation of nucleotide 980A>C, predicting the amino acid 327 substitution of Asn to Thr. Frequencies of the 6 alleles are ha 46.67%, hb 38.33%, hc 5.00%, hd 1.67%, he 3.33%, and hf 5.00%, respectively. These findings in the Taiwanese population confirm previous observations in other populations that the Bombay and para-Bombay phenotypes are due to diverse, sporadic, nonfunctional alleles, predominantly ha and hb, leading to H deficiency of red blood cells. In contrast to previous reports of non-prevalent associations of h alleles with para-Bombay phenotype, our results suggest a regional allele preference associated with para-Bombay individuals in Taiwan.
Chen
Ding-Ping
DP
Department of Clinical Pathology, Chang Gung Memorial Hospital, Taoyuan, Taiwan, ROC.
Tseng
Ching-Ping
CP
Wang
Wei-Ting
WT
Peng
Chien-Ting
CT
Tsao
Kuo-Chien
KC
Wu
Tsu-Lan
TL
Lin
Kuan-Tsou
KT
Sun
Chien-Feng
CF
D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D003001:Cloning, Molecular; D004912:Erythrocytes / Q000201:enzymology / Q000276:immunology; D005647:Fucosyltransferases / Q000097:blood / Q000172:deficiency / Q000235:genetics*; D005820:Genetic Testing; D006801:Humans; D010641:Phenotype; D017354:Point Mutation; D013624:Taiwan; D000097631:Galactoside 2-alpha-L-fucosyltransferase
D000017:ABO Blood-Group System; D005647:Fucosyltransferases; D000097631:Galactoside 2-alpha-L-fucosyltransferase