Plasma and urinary beta-hexosaminidase in juvenile diabetes mellitus.

The activity of beta-hexosaminidase (E C 3.2.1.30) in plasma and urine was determined in 99 patients with juvenile diabetes mellitus and in 40 age-matched controls. Plasma enzyme activities were above normal in plasma from diabetics and showed significant correlations with blood glucose and glycosylated HbA1 (GHbA1) but not with the presence of retinopathy. The urinary excretion of beta-hexosaminidase, which is a sensitive indicator of renal injury, was also excessive in the diabetics and showed a significant correlation with blood GHbA1. The results show that plasma and urinary beta-hexosaminidase correlate with parameters of diabetic control and that urinary beta-hexosaminidase may be more sensitive than urinary albumin as an indicator of early renal damage.