Two novel FUT1 alleles that cause para-Bombay phenotype in a Chinese individual.

Abstract

Bombay and para-Bombay phenotypes, which arise from gene mutations of α-1,2-fucosyltransferase FUT1, are very rare in Chinese population. A para-Bombay phenotype Chinese individual with two novel FUT1 mutations was reported here. The peripheral blood and saliva samples of the proband and her family members were collected after informed consent. ABO and H blood group phenotyping was performed by haemagglutination methods. ABO genotype was determined by PCR-SSP kit. A, B, and H antigens in saliva were detected by a hemagglutination inhibition test. Fragments encompassing the full coding region of FUT1 and FUT2 genes were PCR amplified and sequenced. Allelic sequences were validated by cloning and sequencing individual colonies. The serologic reaction results of the proband revealed that A, B, and H antigen were absent on RBCs, but B and H antigen were presented in saliva, and the serum contains anti-H. The proband was assigned as B/O1 by ABO genotyping. Two new heterozygous mutations of FUT1 gene, c.508dupT and c.787A>C, were identified through direct sequencing of PCR-amplified products. TA cloning and sequencing confirmed that two novel mutations were on different alleles. FUT2 gene sequence of the proband is consistent with standard. The other family members of the proband showed normal phenotypes of ABO blood group and their genotypes are consistent with phenotypes. Two novel FUT1 alleles, with the previously not reported mutations c.508dupT and c.787C, respectively, are responsible for the para-Bombay phenotype detected in the sample from the proband.