Determining the genotype of the Rh blood group system in the Maltese population

Abstract

The Rh blood group system is a complex protein based system that consists of more than 50 antigens with more than 200 different RHD alleles and 50 different RHCE alleles. The five most important antigens from this blood group system are the D, C/c and E/e since they are the cause of most alloimmunisations. The Rh blood group system has a vital role in population genetic studies and by DNA typing important medical issues in transfusion practice can be resolved. Blood group genotyping is the method of choice when serological techniques cannot be used. The aim of the study was, to successfully use methods such as polymerase chain reaction (PCR) to determine the frequency of the RH genotype in the Maltese population. Blood donor samples (n=400) and cord blood samples (n=397) were enrolled in this study. An allele-specific polymerase chain reaction (AS-PCR) method was used to determine the presence of RHD, RHCE*E and RHCE*e, while multiplex PCR was used to test for RHCE*C/c. PCR products were then separated on agarose gel and visualised with ethidium bromide. In these samples, the incidence of RHD was approximately 90% and the remaining samples were negative for the RHD allele. The most common allele was RHCE*e with a percentage of 98% in blood donors and 99% in cord bloods. The most common genotype in RhD positive samples was DCcee and in RhD negative it was dccee. The most common haplotype was DCe making DCe/DCe the most common probable genotype. Like in previous studies, this research also concludes that the distribution of the RII genotype varies in different geographical areas.