Reduced Activity of Serum β-Glucuronidase in Marfan Syndrome

Abstract

Reduced activity of serum β-glucuronidase (EC 3.2.1.31) was found in three patients with Marfan syndrome, two of whom were siblings. The serum β-glu curonidase levels in the patients ranged from 294 to 439 μg (360.7±73.2, mean±SD) of the released P-nitrophenol/100 ml of serum/hour, whereas those of 7 healthy subjects ranged from 564 to 1445 μg (836.4±287.3). This difference was statistically significant (p < 0.01). Plasma glycosaminoglycan levels in the patients were lower than those in the healthy subjects, owing mainly to the differences in plasma high-sulfated glyco saminoglycan. The correlation coefficients of serum β-glucuronidase activity with high-sulfated and total plasma glycosaminoglycans were 0.794 and 0.809, respectively (p<0.01 and p < 0.005, respectively). The results suggest that the decreased plasma high-sulfated glycosaminogly can levels in Marfan syndrome are due to the reduction of serum β-glucuroni dase, which leads to the decreased degradation of macromolecules and, subsequently, the accumulation of the glycosaminoglycans in the tissues.