Cardiovascular findings and effects of enzyme replacement therapy in patients with mucopolysaccharidosis type VI

OBJECTIVE
The mucopolysaccharidoses (MPS) are an important group of lysosomal storage diseases. Commonly reported cardiac involvement includes mitral leaflet thickening and accompanying prolapsus, regurgitation, and rarely, stenosis. The aim of this study was to evaluate cardiac involvement in patients with MPS type VI.

METHODS
The study included a total of 13 children with MPS type VI who were admitted to a single pediatric department between 2016 and 2018. Cardiac status was evaluated prospectively with clinical findings, electrocardiography, and echocardiography. The age of the patients (8 boys, 5 girls) ranged between 2 and 14 years (median: 9 years).

RESULTS
No arrhythmia was observed in any patient. Thickening of the mitral valve with or without regurgitation and prolapsus was the most common lesion seen. Additional involvement of the aortic valve was detected in 12 (92.3%) patients, and additional involvement of the tricuspid valve in 4 (30.8%). Isolated septal hypertrophy was found in 2 patients, and congestive heart failure in another.

CONCLUSION
Cardiac involvement is frequent in MPS. Mitral valve deformation is the most frequent finding. An echocardiographic examination should be performed periodically even if the patient has no clinical signs of cardiac disease, and any cardiac involvement should be kept under control with medical treatment.