Screening Mucopolysaccharidosis Type IX in Patients with Juvenile Idiopathic Arthritis

Mucopolysaccharidosis is a group of lysosomal disorders of a deficiency of specific enzyme required for glycosaminoglycan degradation. Mucopolysaccharidosis type IX is the rarest form of mucopolysaccharidosis. To date, only four patients have been reported. The first reported patient had mild short stature and periarticular soft tissue masses; the other reported patients are clinically indistinguishable from juvenile idiopathic arthritis. In the present study, we screened mucopolysaccharidosis type IX among patients with juvenile idiopathic arthritis with hyaluronidase enzyme assay. One hundred and eight patients with JIA and 50 healthy age-matched control subjects were enrolled in the study. Among all patients, none had deficient hyaluronidase activity. Though serum Hyal-1 activity was significantly increased in JIA patients, compared with control subjects (p < 0.000), no correlation was found between CRP, ESR, and Hyal-1 activity (p = 0.187). In conclusion, the data reported in our study indicates that systemic metabolic investigation for hyaluronidase activity is not recommended in all patients with JIA.