Objective: It has been suspected that the mast cell chymase gene (CMA1) is important for the generation of angiotensin II and therefore might be associated with the pathogenesis of hypertension.
Methods: We sequenced the promoter region, exons, and exon-intron junctions of CMA1 and found 13 single-nucleotide polymorphisms, two of which were loss-of-function mutations. The loss-of-function mutations resulted in: (1) a premature stop codon; and (2) atypical splicing which creates a frame-shift and a stop codon. To elucidate the role of CMA1 in blood pressure regulation, we conducted an association study using these polymorphisms, including the loss-of-function mutations. The study population consisted of 1859 subjects, selected consecutively from the Suita study, an epidemiological cohort representing the general population in Japan.
Results: There was no difference in the genotype distribution of the polymorphisms we studied between hypertensive and normotensive subjects, among either men or women. Moreover, neither of the heterozygous loss-of function mutations had a significant effect on blood pressure values.
Conclusion: Our data suggest that CMA1 is unlikely to influence blood pressure levels in the Japanese population.