Polymorphisms of renin-angiotensin system genes in childhood IgA nephropathy

Byline: Kyoko Maruyama (1), Mami Yoshida (1), Hisahide Nishio (2), Taku Shirakawa (1), Takashi Kawamura (3), Ryojiro Tanaka (4), Hajime Nakamura (5), Kazumoto Iijima (5), N. Yoshikawa (6) Keywords: KeywordsaIgA nephropathy; Children; Angiotensinogen gene; Angiotensin-converting enzyme gene; Urinary protein excretion Abstract: We investigated whether polymorphisms of the renin-angiotensin system genes are involved in IgA nephropathy in Japanese children. We identified the M235T polymorphism of the angiotensinogen (AGT) gene, the I/D polymorphisms of the angiotensin-converting enzyme (ACE) gene, and the A1166C polymorphism of the angiotensin II type 1 receptor gene in 95 Japanese children with IgA nephropathy and 99 healthy Japanese adults. There were no differences in the genotype and allele frequencies of these genes between patients with IgA nephropathy and controls. Urinary protein excretion at the time of biopsy was significantly greater in patients with the TT genotype of the AGT gene than in those with the MM/MT genotypes of the AGT gene (1.32+- 1.42 versus 0.75+-0.78 g/day P=0.01) and in patients with the ID/DD genotypes of the ACE gene than in those with the II genotype of the ACE gene (1.45+-1.50 versus 0.63+-0.56 g/day P=0.001). Thus, the TT genotype of the AGT gene and the ID/DD genotype of the ACE gene are associated with increased severity of proteinuria, suggesting that AGT and ACE gene polymorphisms may play a significant role in the progression of IgA nephropathy in Japanese children. Author Affiliation: (1) Faculty of Health Science, Kobe University School of Medicine, Kobe, Hyogo, Japan, JP (2) Department of Public Health, Kobe University School of Medicine, Kobe, Hyogo, Japan, JP (3) Center for Student Health, Kyoto University, Kyoto, Japan, JP (4) Department of Pediatrics, Hyogo Prefectural Awaji Hospital, Sumoto, Hyogo, Japan, JP (5) Department of Pediatrics, Kobe University School of Medicine, Kobe, Hyogo, Japan, JP (6) Department of Pediatrics, Wakayama Medical University, 811-1 Kimiidera, Wakayama City, Japan 641-8510 e-mail: nori@wakayama-med.ac.jp Tel.: +81-73-4410632, Fax: +81-73-4449055, JP Article note: Received: 21 July 2000 / Revised: 8 December 2000 / Accepted: 11 December 2000