A novel FUT1 variant, c.[35C>T;133_136dupCGCC], underlies a group A para-Bombay phenotype in a Chinese blood donor.

BACKGROUND AND

OBJECTIVES

The para-Bombay phenotype is characterized by H antigen deficiency and the natural production of antibody against the I and H antigens (anti-IH), some of which are occasionally clinically significant. It genetically results from the presence of two non-functional FUT1 alleles coupled with at least one functional FUT2 allele. We present the serological and molecular characterization of a para-Bombay phenotype case, which led to the identification of a novel FUT1 allele.

MATERIALS AND

METHODS

A sample from a blood donor was identified as a result of a discrepancy between forward and reverse typing. This sample subsequently underwent serological typing for A, B and H antigens in accordance with the American Association of Blood Banks Technical Manual. Furthermore, Sanger sequencing and nanopore sequencing were employed to analyse the ABO, FUT1 and FUT2 genes.

RESULTS

The donor was found to have an H-deficient phenotype and the presence of anti-IH. Sanger sequencing identified an ABO*A1.01/ABO*O.01.02 genotype. Nanopore sequencing showed a compound heterozygous state in FUT1, represented by the FUT1*01W.09 allele and a novel FUT1 allele carrying the c.[35C>T;133_136dupCGCC] variant. The FUT2 genotype was determined as FUT2*01/FUT2*01W.02.01.

CONCLUSION

This study identifies a novel FUT1 allele characterized by the c.[35C>T;133_136dupCGCC] variant that impairs H antigen expression on red blood cells, thereby contributing to the understanding of FUT1 allele diversity.