The resulting clinical spectrum ranges from the classical infantile form presenting soon after birth, that is characterized by hypertrophic cardiomyopathy and marked muscle weakness, and leads to death usually before the first year of age, to a milder form characterized by gradually progressing miopathy and respiratory insufficiency with either juvenile

or adult onset. These latter lead progressively to varying degrees of disability Inhibitors,research,lifescience,medical and are associated to reduced life expectancy on average. The different disease phenotypes correlates with the levels of residual α-GA activity in muscle; less than 3% of normal enzyme activity is found in severe infantile cases and residual levels ranging 3 – 30% of normal are found in less severe Inhibitors,research,lifescience,medical late onset forms (2). Several published studies support the effectiveness of ERT with alglucosidase alpha in inducing significant improvement of motor and heart functions and dramatic extension of survival time in infants with the classic form of Pompe disease (3). Although the effects of long-term therapy are still unknown and a marked variability in the

individual response to the drug is undeniable, these Inhibitors,research,lifescience,medical encouraging data make advisable starting ERT with alglucosidase alpha as soon as possible both in affected infants and symptomatic adults. Follow-up of patients with lateonset Pompe disease should be continued for several years to assess the full efficacy of treatment. In view of the high cost of ERT, it is also advisable to perform a careful long term observation of untreated pre- and mildly-symptomatic patients to identify, if possible, markers that allow prediction of the clinical evolution. This in Inhibitors,research,lifescience,medical order to distinguish patients needing ERT treatment Inhibitors,research,lifescience,medical from patients who can maintain autonomy and a good quality of life being supported from exercise therapy,

diet, and assisted ventilation when adequate. The diagnosis of the classic infantile form of Pompe disease is made, usually, early and relatively easily because, due to the marked severity of the symptoms of the disease yet at it onset, the little patients are immediately admitted Phosphoprotein phosphatase to pediatric intensive care centers where physicians are well trained to this website recognize the disease. Conversely, the diagnosis of late-onset forms is complicated by the rarity of the condition and the heterogeneity of the clinical manifestations, which vary with respect to organ involvement, age at onset, and severity. Symptoms are often unspecific especially at onset and they may remain mild even for decades so that neither the patient nor the doctor consider to deepen diagnostic procedures. The diagnosis of Pompe disease requires the knowledge of the clinical presentation which is highly variable with respect to age at onset, disease severity, organ involvement, and clinical course.