A case report of a rare p phenotype individual and a review of molecular biological analysis of p phenotype in the Chinese population
Xiaoxiang Wei, Dong Xiang, Liangfeng Fan, Zhonghui Guo, Dong Ran, Shengdi Bu, Xiaojie Tan, Qin LiAbstract
Objectives
To explore the serological characteristics and molecular mechanisms of an individual with the p phenotype in the Chinese population by analysing the serological and genetic background.
Background
The p phenotype, which lacks all antigens in the P1PK blood group system, is extremely rare in the Chinese population. Individuals with the p phenotype typically produce anti‐PP1Pk antibodies. The P1, Pk antigens belong to the P1PK blood group system, while the P antigen is part of the GLOB blood group system. The antigens in the P1PK system are synthesised by α1,4‐galactosyltransferase (α4Gal‐T), while the antigens in the GLOB system are produced by 3‐𝛽‐N‐acetylgalactosaminyl‐transferase (β3GalNAc‐T1). These glycosyltransferases are encoded by the A4GALT and B3GALNT1 genes.
Materials and Methods
Serological techniques were employed to determine the blood types and antibodies of an individual with the p phenotype. Additionally, first‐ and third‐generation sequencing methods were used to analyse the A4GALT and B3GALNT1 genes in the sample.
Results
The serum from the tested individual showed positive reactions with all red blood cells (RBCs) from two sets of panel RBC reagents, while it reacted negatively with a confirmed p phenotype red blood cell. The antibodies in the serum exhibited IgM + IgG properties, with IgG being the predominant type. The antibody titers at room temperature, 37°C, and 4°C were 128, 64, and 256, respectively. Sequencing analysis revealed a homozygous mutation in the A4GALT gene at rs5751348: G > T; c.343A > T; c.903C > G, while no mutation was detected in the B3GALNT1 gene.
Conclusions
The tested individual exhibited the p phenotype and likely produces anti‐PP1Pk antibodies. The allele carrying rs5751348: G > T; c.343A > T; c.903C > G in the A4GALT gene has been provisionally designated A4GALT*02 N.28 (pending official recognition by ISBT).