Description of the first case of c.137-8C>T GYPB mutation not associated to the GYPB(P2) allele

Abstract

Short Description

During a blood donor routine genotyping, we repeatedly had an indeterminate call (IC) for GYPB*S with the BioArray HEA v1.2 BeadChip kit. By sequencing DNA, the molecular presence of cytosine and thymine was found at the polymorphic site rs7683365 (c.143T/C), predictive of S(+) and s(+) antigens. Moreover, a heterozygous polymorphism c.137-8C/T was detected, which is located in the HEA probe binding region and is known to induce a failure in genotyping with the BeadChip^TM technology. No evidence was found for c.270+5G/T polymorphism, which is characteristic of P2 allele. Serological testing for S and s with Grifols sera and automatic system showed a weak expression of S and a normal expression of s antigens. To the best of our knowledge this is the first description of a case where this gene alteration is not associated with the presence of a P2 allele.