Cardiac involvement in Lysosomal Storage Diseases.

Lysosomal storage diseases (LSDs) include a heterogeneous group of rare, inborn, metabolic diseases characterized by deficiency of lysosomal enzymes or of other proteins involved in lysosomal function, leading to multi organ system substrates accumulation, with consequent multi systemic clinical presentation. Cardiac disease is particularly important in some group of LSDs as glycogen storage diseases (Pompe), mucopolysaccharidoses and in glycosphingolipidoses (Anderson-Fabry disease and less frequently Gaucher disease). Various cardiac manifestations may be observed including hypertrophic and dilated cardiomyopathy, coronary artery disease and valvular disease. The availability of enzyme replacement therapy (ERT) has changed the natural history of some LSDs such as Pompe disease, thanks to the significant effects on cardiological involvement. In other LSDs such as MPSs or Fabry disease, ERT has been shown to stabilize or slow the progression of heart damage. This imposes the need for a timely diagnosis that allows a rapid onset of ERT.

Prevalence of elevated pulmonary artery systolic pressure in Down Syndrome young patients with and without congenital heart disease.

This study examined the prevalence and distribution of elevated systolic pulmonary arterial pressure, measured by echocardiography, in young patients with down syndrome associated or not with congenital heart disease and surgical correction during childhood. Pulmonary artery systolic pressure, computed by regurgitant tricuspid flow velocity evaluation, is the most frequently used parameter for the screening of pulmonary hypertension. Down syndrome and congenital heart disease often coexist and the probability to detect elevated systolic pulmonary arterial pressure in this setting is high. However, little is known about the evaluation of pulmonary arterial pressure during growth of patients with down syndrome with or without congenital heart disease. We enrolled 47 young patients (55% of male sex; mean age: 18.4 ± 6.0 years), 40 with congenital heart disease and 7 without a cardiac defect. Systolic pulmonary arterial pressure was assessed by echocardiography. No difference was found in the population dichotomized by presence or absence of CHD. Only male sex (p=0.000), highly sensitive troponin-T (P=0.027), tricuspid annular plane systolic excursion (TAPSE, p=0.045) and sPAP (p=0.004) were elevated in surgical group. The ASD was found as, the most common structural abnormality in our patients (50%), followed by VSD (27.5%) and complex CHD (such as complete atrioventricular canal defect, CAVC = 25% and Fallot disease = 15%). Furthermore, about 45% of patients had the combined defect. Only 37.5% of patients underwent to corrective surgery during the first months of life. We observed a significantly increase of sPAP values in patients with complex CHD, such as CAVC (p=0.019) and Fallot disease (p=0.001) but, in the following multivariate analysis performed in the patients with CHD, only Fallot disease remains as independent predictors of elevated values of sPAP (p=0.022). An elevated systolic pulmonary arterial pressure may represent the key screening tool in the diagnostic assessment of suspect pulmonary arterial hypertension in high risk population with down syndrome regardless the presence of congenital heart disease.

Renal involvement in paediatric Fabry disease.

Anderson-Fabry Disease (AFD) is a rare, X-linked inborn error of glycosphingolipid catabolism caused by a deficient or absent activity of the lysosomal enzyme, α-galactosidase A, resulting in the progressive multisystem lysosomal accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3). Among the wide spectrum of clinical signs and symptoms and the life-threatening complications of Fabry disease, renal failure causes significant morbidity and mortality. Various evidence shows that the accumulation of Gb3 in different renal cells is present since the first years of life, many years and usually decades before manifest symptoms and signs of renal involvement. Early renal damage can be demonstrated by clinical signs as microalbuminuria and proteinuria, developing as early as in the second decade of life. A decline in GFR is uncommon at paediatric ages but may be seen as early as adolescence. Renal biopsy is rarely used in paediatric patients with Fabry disease although evidence shows that it may be considered a valid tool for the diagnosis of early and potentially reversible nephropathy, as well as for the evaluation of the effectiveness of enzyme replacement therapy (ERT). Although there is consensus in considering the early initiation of ERT as the only tool able to prevent the progression of nephropathy, the issue on the correct timing for the onset of ERT in pediatric age remains open in the management of this chronic and progressive disease.