Increased chymase expression has been observed in humans with diabetic nephropathy (DN) (Huang, Chen, & Truong, 2003; Ritz, 2003), IgA nephropathy (Konishi et al., 2008; Sakamoto‐Ihara et al., 2007), autosomal dominant polycystic kidney disease (McPherson et al., 2004), hypertensive nephropathy (Welker et al., 2008) and obstructive uropathy (Pons et al., 2017) suggesting a central role of chymase in many forms of kidney disease in humans. This evidence concerns the gene CMA1 and diabetic kidney disease.