Glycogen Storage Disease type IIIa (GSD IIIa) is an inborn error of carbohydrate metabolism caused by impaired glycogen debranching enzyme (GDE) activity. The ageing GSD IIIa cohort shows that muscle involvement -despite dietary management- is a common disabling phenotype in adulthood. Currently, no specific therapy has been established for muscle problems in adult GSD IIIa patients.~However, it could be hypothesized that nutritional ketosis (NK) will be highly beneficial to patients. Amongst others, ketone bodies could take on the role of primary energy source in exercising muscle. Recently, acute NK in exercise was studied in humans. NK was found to enhance muscle mitochondrial function in athletes.~The investigators will study if acute NK in adult GSD IIIa patients can boost muscle mitochondrial function in vivo.
The investigators will study if acute nutritional ketosis in adult GSD IIIa patients can boost muscle mitochondrial function in vivo.