Osteoarthropathy in mucopolysaccharidosis type II

INTRODUCTION: Mucopolysaccharidosis type II (MPS type II, Hunter syndrome) is a rare (~ 1/1500.000), X-linked inherited disorder (affects boys) due to deficiency of the lysosomal enzyme iduronate sulfatase (Xq.28). The complex clinical picture includes osteoarthropathy with a tendency to flexion stiffness and disability. In our country, the specific diagnosis and enzyme replacement therapy (ERT), are recently available in the Center for Genetic Pathology Cluj. OBJECTIVES: Assessment of clinical features, radiological and imaging of osteoarthropathy in MPS type II and their evolution under ERT. MATERIAL AND METHODS: The study included 9 male patients with a suggestive clinical picture of MPS type II; the diagnosis was confirmed by enzymatic assay and the patients were treated with ERT. Osteoarthropathy was assessed before treatment: a) clinical tests (joint goniometry, walking test) and b) radiology (X-rays of the hand and wrist, spine and pelvis), bone densitometry in five patients. Clinical tests were repeated after therapy. RESULTS: Chronic osteoarthropathy was present in all patients. Joint mobility was reduced with quasi stationary trend after 12 months of treatment. The walking test was improved after treatment. Radiological assessment revealed: hand bones changes, delayed bone age, vertebral changes, pelvis changes, kipho-scoliosis and aseptic necrosis of the femoral head in 100%, 88%, 88%, 55% and 11% respectively. Bone mineral density was normal in five of the nine patients evaluated. CONCLUSIONS: Chronic osteoarthropathy with flexion stiffness is an essential component of the clinical picture of MPS type II. ERT allows an improvement/arrest of evolution (depending on disease severity and time of initiating therapy).