Features and behavior of valvular abnormalities in adolescent and adult patients in mucopolysaccharidosis: an echocardiographic study.

Mucopolysaccharidoses, a rare inherited disorder of lysosomal storage, account for less than 0.1% of all genetic diseases.  The penetrance is highly variable and clinically it varies from severe fetal-neonatal forms to attenuated diseases diagnosed in adult individuals. The majority of the patients have been reported to show cardiac abnormalities since pediatric age, however, there is a minority of patients with attenuated disease diagnosed in the adolescent and adult age. The haematopoietic stem cell transplantation and enzyme replacement therapy are the current therapies for these disorders. Thanks to these treatments, Mucopolysaccharidoses patients live longer than in the past. Even though enzyme replacement therapy has been demonstrated to reduce left ventricular mass in patients with cardiomyopathy, the efficacy on valve abnormalities has not been clearly demonstrate yet. Furthermore, thanks to the current therapy, to better understanding and to the advent on new technologies, an increasing number of adolescent and adult patients diagnosed with MPS are followed up in the adult echocardiographic laboratory. Indeed, a systematic descriptive study describing the echocardiographic features of valvular involvement and their evolution in adolescent and adult patients lacks of medical literature and this was the aim of our investigation. Our results showed that all the valves are affected, mainly the mitral valve with a higher prevalence compared to the pediatric age.  The echocardiographic features of MPS differs from other valvular disease of adolescent and adult age, and knowing them can avoid misdiagnosis. Our observations also suggest that the progression of cardiac involvement slows after the initiation of the therapy in our group of age. Further studies on larger population are required to confirm our results.