Identification of a Novel P1PK Allele (a4galt*c.1‐504_1044del1548) in Two Chinese Sisters with a History of Recurrent Spontaneous Abortion

The high-prevalence P antigen of the GLOB system, and the polymorphic P1 and high-prevalence P antigens of the P1PK system are synthesized by the globotriaosylceramide 3-β-N-acetylgalactosaminyltransferase (β1,3GalNAcT1) and 4-α-galactosyltransferase (α1,4Gal-T) respectively, which encoded by the B3GALNT1 and A4GALT genes independently. The A4GALT gene encompasses four exons, but the whole coding region is all located on exon 3. Besides, the single-nucleotide polymorphisms (SNPs) in intron 2a of A4GALT, particularly rs5751348, correlate with P1 (P1-positive) or P2 (P1-negative) phenotypes, respectively. The individuals expressing strong P but lacking P antigens are the rare P phenotype resulting from the B3GALNT1 mutations, which include P1 k