Glycogen storage disease type 1: impact of medium-chain triglycerides on metabolic control and growth.

OBJECTIVE

Hypoketotic hypoglycaemia and hypertriglyceridaemia are biochemical hallmarks of glycogen storage disease (GSD) 1. Increased malonyl coenzyme A production which compromises oxidation of long-chain fatty acids via carnitine palmitoyltransferase (CPT) 1 inhibition plays a crucial role in the pathogenesis of these complications. Therapy consists primarily of nutritional support including frequent carbohydrate-rich meals. We studied the effect of a diet enriched in medium-chain triglycerides (MCT) on metabolic control/growth in GSD 1 as medium-chain fatty acids can be oxidised independently of CPT 1.

METHODS

An adult female, a 1.6-year-old boy with GSD 1a and a 6.5-year-old girl with GSD 1b treated with a classical GSD diet were enrolled; their 'classical GSD diet' was supplemented with MCT fats. Concentrations of glucose, lactate, ketone bodies triglycerides, uric acid, acylcarnitines in blood and organic acids in urine were determined.

RESULTS

No clinical or biochemical side-effects were observed. The MCT diet led to a decrease in uric acid concentrations in all patients. Triglyceride levels were reduced only in the youngest patient, while lactate concentrations did not significantly decrease. The MCT diet allowed for a reduction in carbohydrate and caloric intake required to maintain euglycaemia and led to improvement in growth in the two prepubertal patients.

CONCLUSIONS

MCT supplementation had a positive effect on metabolic control and growth in our patients suffering from GSD 1.