<qa>  What is the mean for age for the patient?- The patient must have a clinical diagnosis of infantile GSD-II as defined by: a the patient hashad documented in a medical record onset of symptoms compatible with GSD-II by 12 months of age; b the patient has documented GAA deficiency as illustrated by an endogenous GAA activity less than or equal to 2 of the mean of the normal range as assessed in cultured skin fibroblasts; AND c the patient has a Left Ventricular Mass Index greater than 2 standard deviations above the mean for age 