Institution: | aDepartment of Pediatric Endocrinology and Diabetes, Princess Margaret Hospital, Perth, WA, Australia bLaboratory of Genetic Epidemiology, Western Australian Institute for Medical Research, Perth, WA, Australia cSchool of Population Health, University of Western Australia, Perth, WA, Australia dCenter of Child Health Research, Telethon Institute of Child Health Research, Perth, WA, Australia eClinical Biochemistry, PathWest, Queen Elizabeth II Medical Center, Perth, WA, Australia fSchool of Surgery and Pathology, University of Western Australia, Perth, WA, Australia |
Abstract: | AIM: We examined genetic polymorphisms in the renin-angiotensin system (RAS) coding for angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) for angiotensinogen (AGT) M235T and angiotensin II receptor type 1 (AGTR1) A1166C as predictors for the development of microalbuminuria (MA) in children with type 1 diabetes mellitus (T1DM). METHODS: Four hundred fifty-three (215 males, 238 females) T1DM children median (interquartile range): age, 16.7 years (13.9-18.3); diabetes duration, 6.9 years (3.3-10.8); age at diagnosis, 9.1 years (5.8-11.8)] were followed prospectively from diagnosis until the development of MA (two of three consecutive overnight urine samples with albumin excretion rates of > or =20 and <200 microg/min). Kaplan-Meier survival curves and Cox proportional multivariate model estimated the probability of developing MA and the relative risk for MA among different variables. RESULTS: MA developed in 41 (9.1%) subjects. The frequencies of genotypes were as follows: ACE-II 112 (25%), ACE-ID 221 (49%), and ACE-DD 117 (26%) (n=450); AGT-MM 144 (32%), AGT-MT 231 (51%), and AGT-TT 77 (17%) (n=452); AGTR1-AA 211 (47%), AGTR1-AC 204 (45%), and AGTR1-CC 37 (8%) (n=452). The cumulative risk for the development of MA was higher in ACE-DD versus ACE-ID/II groups (log-rank test, P=.05), and a trend was noticed when AGT-TT was compared to AGT-MT/MM groups (log-rank test, P=.08). AGT-TT polymorphism conferred a fourfold increased risk for MA compared to AGT-MM/MT (hazard ratio=3.8; 95% confidence interval=1.43-10.3; P=.008). INTERPRETATION: Our findings suggest that RAS gene polymorphism at AGT M235T is a strong predictor for early MA in young T1DM subjects. |