Rodinná studie polymorfismu antigenů systému MNS

Abstract

Background: Mutations in the genes GYPA and GYPB encoding the MNS system can cause reduced to absent expression of antigens on the surface of red cells. This may lead to discrepant findings between immunohematological and genetic results. The aim of this study was to demonstrate that the discrepant finding in the investigation of MNS system antigens may be caused by a mutation in gene GYPB and to investigate whether this mutation is also present in the patient's offspring.

Materials and methods: In 2019, patient A1 was examined for the extended MNS phenotype by immunohematology using the column and tube agglutination methods at the Transfusion Department of the Regional Hospital Liberec (KNL), as. At the Institute of Hematology and Blood Transfusion (IHBT), the findings were confirmed by column agglutination and genotyped by Fluogene PCR. In 2022, the blood samples of patient A1's offspring were examined by immunohematological methods: phenotype by column agglutination and solid phase method at the Transfusion Department, KNL, and by column agglutination at IHBT. Genetic testing was performed by real-time PCR ERY Q KKD/MNS-TYPE at the Department of Genetics and Molecular Diagnostics (OGMD), KNL, and by PCR methods: PCR Fluogene and ID CORE XT at IHBT.

Results: In patient A1, discrepant findings in antigen S were found: antigen phenotype S-s+ and genotype S+s+. All blood relatives of the patient (descendants) were examined - 9 in total (3 sons, 1 daughter, 4 grandchildren and 1 great-grandchild). The proband's descendants were found to have S+ or S- antigen, but there was never a discrepant result between immunological and genetic methods.

Conclusion: In patient A1, a discrepant finding was observed in the results of the antigen S, which was most likely caused by a genetic change in the glycophorin B gene. This mutation was not passed on to any of the offspring.