Atypical associations between DIA and DIB alleles and the band 3-Memphis mutation in Amazonian inhabitants

Background and Objectives The Diego blood group system has a great anthropological and transfusion medicine importance, being associated with immediate, delayed haemolytic reactions and haemolytic disease of new born. Its 22 antigens are located on the integral band 3 glycoprotein, which is encoded by the SLC4A1 gene. We studied the frequency of DI*A, DI*B alleles, band 3 (166A) and band 3‐Memphis (A166G) in individuals from the Brazilian amazon. To investigate atypical associations between DI*A, DI*B alleles, band 3 and band 3‐Memphis. Materials and Methods Genetic sequencing was performed with custom primers in 302 patients divided into four groups as follows: Group A (anaemic patients with erythrocyte membrane changes), Group B (anaemic patients without erythrocyte membrane changes), Group C (patients without anaemia with erythrocyte membrane changes) and Group D (healthy individuals). Results A frequency of 63 (20·9%) individuals having band 3‐Memphis was identified, of which 54 (17·9%) were heterozygous and 09 (3%) homozygous. The Diego system genotypic frequency was DI*A/DI*B (9·93%), DI*A/DI*A (0·90%), DI*B/DI*B (89·0%), of which the followed atypical associations were found: 14 (43·75%) DI*A allele associated with a homozygous 166A nucleotide polymorphism and 16 (2·82%) DI*B allele associated with homozygous 166G polymorphism; interestingly, this last one was found only in the B group. Conclusions These findings are important to understand the genetic associations between Diego blood group system and band 3 protein as well as to comprehend these atypical associations and their anthropological and haematological significance.