Introduction: The prevalence and severity of cardio-vascular disease in patients with mucopolysaccharidosis (MPS) is high and progressive, consisting in seve-re cardiac valve disease and ventricular hypertrophy. Enzyme replacement therapy in MPS may improve the organ impairment.
Objective: To characterize the cardiac disease and the results of enzyme replacement therapy in children with MPS type I and MPS type II.
Methods: We evaluated 24 patients with mucopolysa-ccharidosis (MPS): 5 patients with MPS type I, 18 patients with MPS type II, one patient with MPS type IV. We assessed the function of valves, left ventricular chamber dimensions, septal and posterior ventricular wall thicknesses, systolic and diastolic function of the ventricles, pulmonary hypertension at every 6 months. The treatment of these patients consisted in weekly administration of recombinant form of human alpha-L-iduronidase in dose of 0.58 mg/kg iv weekly for the patients with MPS type I and iduronate 2-sulfatase in dose of 0.5 mg/kg, iv weekly for patients with MPS type II.
Results: At diagnosis, all patients presented echocardiographic alterations. Mitral valve thickening with variable grades of regurgitation was diagnosed in all patients, aortic regurgitation was present in 14 patients and mi-tral stenosis in 2 patients. Left ventricular hypertrophy was diagnosed in 10 patients. Mild pulmonary hyper-tension was present in 4 patients. The mean age of the patients at starting therapy was 6.1 years. The treatment results on valvular heart disease were: stable disease in 14 patients, mild improvement in 4 patients and aggravation in 3 patients. Ventricular hypertrophy remained unmodified in 6 patients and worsened in one patient.
Conclusions: T he most prevalent cardiac changes in children with MPS are valvular lesions. Enzyme repla-cement therapy had little effect on cardiac disease in children with MPS.