DIETARY-TREATMENT IN LATE-ONSET ACID MALTASE DEFICIENCY

Late-onset acid maltase deficiency or glycogen storage disease type IT (GSD II) is a rare disorder of intralysosomal glycogen metabolism, re sulting in progressive myopathy that is secondary to increased muscle protein breakdown. Stable isotope studies in the postabsorptive state have confirmed that mean protein breakdown in GSD II. is increased by 31% compared to control subjects, 6.86 versus 4,69 g/kg per day, that mean protein balance is reduced in GSD II -1.32 versus -1.06 g/kg per day. Indirect calorimetry has demonstrated an increase in mean resting energy expenditure in GSD LT, 41.8 versus 31.2 kcal/kg per day. Compl iance following the introduction of a high-protein diet is often poor due to the large quantities of protein necessary and to the high calor ic intake with the consequent weight gain. Only 25% of all reported su bjects with GSD II showed an improvement of muscle or respiratory func tion after a high-protein diet. Careful evaluation of the underlying p athophysiological changes in GSD LT is necessary to develop more logic al and therefore more beneficial forms of dietary treatment.