80 Genetics Heart and cardiovascular involvement in Russian patients with mucopolysaccharidosis: effects of enzyme replacement therapy

Mucopolysaccharidosis is a rare lysosomal storage disorder. Clinical phenotype is very variable. Patients usually have short stature, multiplex dysostosism, facial dysmorphism, cardiovascular abnormalities and other changes We study cardiovascular and heart findings in patients with mucopolysaccharidosis II (MPS II) and effect after enzyme replacement therapy (ERT). 55 boys were included in our study. Cardiac problem has 49 patients (median age 85,00±7,26 (3-207) month). ERT was given to 46 patients since 2008 (median age 81,54±50,24 month). Before ERT, mitral regurgitation had 27 patients, thickening of the mitral valve – 17, stenosis mitral valve 1, aortic regurgitation – 20 patients, thickening of the aortic valve – 6, stenosis aortic valve -1, tricuspid regurgitation 13 patients, pulmonary valve regurgitation – 4. After ERT – mitral regurgitation had 35 patients, thickening of the mitral valve – 20, stenosis mitral valve – 0, aortic regurgitation – 23 patients, thickening of the aortic valve – 35, stenosis aortic valve -0, tricuspid regurgitation – 14 patients, pulmonary valve regurgitation -3. There were no statistically significant deterioration or improvement of the valve heart apparatus in the examined group of patients. (P>0,05). Cardiomyopathy (left ventricular hypertrophy) have 6 boys with MPS II before and after ERT, lung hypertension – 2 cases before ERT, 4 – after. The course of heart failure in MPS is progressive and we evaluated the heart condition by functional class. We have identified significantly high performance functional class at first patient visit (I class – 44,4% patients, II class – 44,4%). After ERT (median age 81,54±50,24 month) 89% patients have no negative dynamics. It should be noted that most patients began receiving ERT at age 6-8 years old, they had severe somatic and neurological symptoms. ERT is not able to reverse the cardiac damage, but provides stabilization of heart failure. Early initiation of ERT is a factor preventing severe heart disease in MPSII patients.