TUBULAR MARKERS IN CHILDREN WITH INSULIN-DEPENDENT DIABETES-MELLITUS

The aim of the present study was to Investigate the prevalence of tubu lar dysfunction and to assess the clinical significance of low-molecul ar-weight proteinuria and enzymuria. In children with insulin-dependen t diabetes mellitus (IDDM). N.acetyl-beta-D-glucosaminidase (NAG) and beta-microglobulin (beta(2)M) excretion was determined in 52 children with insulin-dependent diabetes mellitus and 28 controls. Patients wer e grouped according to the duration of diabetes: group 1 (n = 7): less than one year; group 2 (n = 27): one to five years; groups 3 (n = 18) : greater than five years. Both parameters were significantly Increase d in groups 2 and 3 compared to controls. Urinary B2M levels correlate d significantly with albuminuria and HbA(1C), while urinary NAG levels correlated only with HbA(1C). Two to four samples were obtained from 35 of 52 diabetic patients in the study group at one-month intervals. Of these, 23 patients had elevated NAG levels, and 22 patients increas ed beta(2)M excretion. However, only six patients displayed persistent enzymuria, and nine low-molecular-weight proteinuria. The mean (SD) o f coefficients of variation of each patient was 50.45 (+/- 28.24) for NAG and 68.25 (+/- 42.57) for beta(2)M excretion. We concluded that ea rly tubular dysfunction and/or damage occurs in IDDM but is not establ ished in the majority of children.