T.P.41

Glycogen storage disease type 3 (GSD3) is an autosomal recessive disorder caused by mutations in the AGL gene coding for the glycogen debranching enzyme, which releases glucose from glycogen. Current therapy is primarily based on dietary modifications but pharmacological approaches are emerging. The pattern of muscle clinical involvement is poorly described in the literature. However, the need for outcome measures is becoming crucial to assess the efficacy of new treatments in future clinical trials. Here we present a cross-sectional study of 17 GSD3 patients aged between 12 and 56 years old. We found that above 20 years of age the Motor Function Measure (MFM) scale total score decreased with increasing age. A negative correlation was found between age and MFM total score (rho = −0.841, p