Three successful pregnancies in a patient with glycogen storage disease type 0

Abstract

Glycogen storage disease type 0 (GSD 0) is a rare inborn error of metabolism due to deficiency of the enzyme glycogen synthase (EC 2.4.1.11). The disorder is clinically characterized by ketotic fasting hypoglycemia in combination with postprandial hyperglycemia and hyperlactatemia. So far, only one pregnancy has been described in a woman with GSD 0. We report a 32-year-old GSD 0 patient with three successful pregnancies. The diagnosis of GSD 0 was made in early childhood due to characteristic symptoms. The patient had two healthy children at the time of her first visit in our metabolic center. The diet was optimized prior to her third pregnancy with a protein-rich diet including cornstarch and protein supplements. Pregnancy was confirmed at week 6 of gestation. Dietary management was difficult during pregnancy, especially in the first trimester due to severe nausea. Labor was induced at 37 weeks of gestation due to cholestasis of pregnancy, and the patient delivered a healthy baby girl. Perinatally, the mother received a high glucose infusion to stabilize blood glucose levels. The neonate also required a glucose infusion postnatally because of impaired glucose homeostasis. Similar to diabetic fetopathy, recurrent maternal hyperglycemia may result in hyperinsulinism of the child and trigger neonatal hypoglycemia. All four pregnancies in women with GSD 0 described to date occurred with minor complications and resulted in healthy offspring, which underpins the good prognosis and rather benign character of this rare metabolic disease. Careful monitoring during pregnancy and delivery is, however, necessary to minimize the risk of recurrent hypoglycemia for both mother and child.

Keywords: GYS2; glycogen storage disease; glycogen synthase; glycogen synthetase; ketotic hypoglycemia; pregnancy.