Sequence analysis of the genes encoding for H+/K+‐ATPase in autoimmune gastritis

Abstract

Background. H+/K+‐ATPase is the target autoantigen in autoimmune gastritis (AIG), an organ‐specific autoimmune disease with a strong hereditary component.Aim. To detect possible polymorphisms in H+/K+‐ATPase α‐ and β‐subunits in AIG patients.Methods. Blood samples from 12 Finnish AIG patients were sequenced for the coding regions of genes encoding for H+/K+‐ATPase α‐ and β‐subunits; 50–52 Finnish anonymous blood donors served as controls. Additionally, parietal cell and Helicobacter pylori antibodies and serum pepsinogen I levels (PG I) were analysed.Results. In the α‐subunit, all patients and controls had C‐allele at the non‐synonymous c.824T>C single nucleotide polymorphism (SNP) resulting in valine substitution for alanine (Val265Ala). In the β‐subunit, a previously unknown non‐synonymous SNP resulting in a substitution of alanine residue for valine (Ala248Val) was found in exon 7 in a single patient and none of the controls. All patients had low serum PG I levels and elevated parietal cell antibodies; three had positive H. pylori serology.Conclusions. At the non‐synonymous SNP c.824T>C in the α‐subunit of H+/K+‐ATPase most Finnish individuals with or without AIG have C allele. Genetic variants of the coding regions of genes for H+/K+‐ATPase α‐ and β‐subunits are not associated with AIG in Finnish patients.