Lewis blood group genetic and phenotypic diversity in a Thai population

The Lewis blood group (ISBT system 007) is a plasma antigen adsorbed onto the red blood cell surface. Relatively few studies have examined the genetic characteristics and expression of this blood group or the associated secretor status in different populations. This study aimed to determine the prevalence of FUT2 and FUT3 gene variants and to investigate the Lewis phenotype and secretor status in a Thai population.

Lewis phenotype and secretor status were determined in 100 blood donors using serological methods, and FUT2 and FUT3 genotypes were identified using Sanger sequencing. Novel mutations were confirmed using polymerase chain reaction-restriction fragment length polymorphism.

Lewis phenotype distribution was Le(a-b-) 15%, Le(a-b+) 55%, Le(a+b-) 12%, and Le(a+b+) 18%, with secretor and nonsecretor frequencies of 76% and 24%, respectively. Three novel heterozygous FUT2 mutations were identified in exon 2 from 3 independent secretor samples: c.387 C>G, c.523 C>T, and c.610 G>C, all confirmed by restriction enzyme analysis. Additionally, FUT2 mutations identified included c.171 A>G, c.216 C>T, c.302 C>T, c.316 G>A, c.357 C>T, c.385 A>T, c.428 G>A, c.480 C>T, c.492 G>C, c.571 C>T, c.739 G>A, c.849 G>A, c.853 G>A, and c.960 A>G. No novel FUT3 mutations were detected; identified FUT3 variants included c.59 T > G, c.202 T > C, c.314 C>T, c.508 G>A, c.612 A>G, c.645 T > C, c.732 C>T, c.882 C>T, c.974 C>T, and c.1067 T > A.

This study identified and confirmed 3 novel FUT2 gene variants, contributing to the genetic database of FUT2 polymorphisms in the Thai population.