Identification of a novel isoform predominantly expressed in gastric tissue and a triple-base pair polymorphism of the cathepsin W gene

In order to investigate the prevalence of potential polymorphisms of the cathepsin W gene, the complete cDNA of 50 dyspeptic patients was analyzed. From those 37 (74%) revealed the wildtype sequence, 6 samples (12%) contained independent single base pair changes including 4 silent and 2 with amino acid changes. Furthermore, a triple-base pair polymorphism was found in 7 samples (14%, 4x heterozygous, 3x homozygous) leading to the following changes: F(217)S, H(248)Y, and I(250)T. Furthermore, a novel alternative splice variant concerning intron 10 was identified in 6 samples (12%). Notably, this novel isoform was only found in samples of gastric mucosa lymphocytes, whereas peripheral NK cells expressed cathepsin W wildtype only. Taken together, this study demonstrated for the fist time that a genetic variant and a novel isoform of cathepsin W are present in about 14% and 12%, respectively, within the Caucasian population.