Study of 467C>T and 745C>T variants of alpha-1, 3-N-acetylgalactoseaminotransferase gene / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To explore the effect of alpha-1,3-N-acetylgalactosaminyltransferase gene variants on A antigen expression in a family where a member was suspected for a rare A3 subtype of the ABO variant.</p><p><b>METHODS</b>Serological assay was carried out to determine the ABO blood group of the proband and his family members. To determine the haploid of the alpha-1,3-N-acetylgalactosaminyltransferase gene of the proband, DNA was extracted and genotyped with sequence-specific primer PCR (PCR-SSP) followed by direct sequencing and cloning of exons 6 and 7 of the ABO locus.</p><p><b>RESULTS</b>Weak A antigen was detected on red blood cells of the proband, while anti-A and anti-B antibodies were detected in his serum. DNA sequencing showed a 261delG mutation in exon 6, and two heterozygote mutations (467C>T and 745C>T) in exon 7 of the alpha-1,3-N-acetylgalactosaminyltransferase gene. Haplotype analysis has identified two alleles A307 and O01. Compared with the A101 allele, the A307 allele has harbored two nucleotides changes (467C>T and 745C>T), which resulted in substitution of two amino acids (P156L and R249W).</p><p><b>CONCLUSION</b>The 467C>T and 745C>T mutations of the alpha-1,3-N-acetylgalactosaminyltransferase gene can result in an A307 phenotype with reduced expression of A antigen.</p>