[A Study of a New Variation of α-1, 3-N-acetylgalactosaminyltransferase Gene in Pedigrees]

To study the characteristics of a novel variant of the α-1,3-N-acetylgalactosaminyltransferase gene in a family through serological and gene sequence analyses of a proband with ABO subtype and her family members.

Blood samples of the proband and four family members were collected. The ABO phenotypes were detected by serological methods, and the ABO blood group genotyping was performed by fluorescence PCR. Direct sequencing was carried out for exons 1-7 of the ABO gene in the proband and family members, and cloning sequencing was conducted for exons 6 and 7.

The serological test showed that the blood group phenotype of the proband was Ael type, and the ABO blood group genotyping result was A/O. Sequencing results indicated that on the basis of the ABO*A1.01 sequence, there were simultaneous variations of c.467C>T and c.664G>A in exon 7 of the A allele, which belonged to a novel variation of the A allele and had been registered in GenBank with the accession number MZ076784.1. Family investigation revealed that the proband, her son and granddaughter all had this novel variation.

On the basis of the ABO*A1.01 sequence, the new variation of the combination of c.467C>T and c.664G>A in exon 7 is a heritable variation. It is speculated that this variation is the cause of the weakened expression of the A antigen.