[Pedigree investigation and genetic analysis of a case with p blood group].

To explore the molecule basis of a p blood group in a patient with gastric carcinoma.,The p phenotype was determined with serological method. Inheritance of the p phenotype was investigated by pedigree analysis. Sequence of α-1,4- galactosyltransferase (A4GALT) gene was determined by Sanger method.,The proband and his younger brother were both determined to have a p phenotype. Two homozygous variations, c.343A>T (AAA>TAA) and c.903C>G (CCC>CCG), have been detected in exon 3 of the A4GALT gene. Among these, c.343 A>T (AAA>TAA) was a novel mutation, which has resulted in a termination codon, with which no normal product of the gene can be produced. c.903C>G was determined to be a polymorphism.,A novel c.343A>T mutation in the A4GALT gene probably underlies the p phenotype, to which a Genbank access number KC202808 has been assigned.