Management of Dysglycemia in a Pregnancy Complicated by Fanconi-Bickel Syndrome.

Background/objective: Fanconi-Bickel Syndrome (FBS) is an inherited disorder of glucose metabolism resulting from functional loss of glucose transporter 2 characterized by fasting hypoglycemia oscillating with postprandial hyperglycemia. Dysglycemia treatment strategies during FBS pregnancy have not been reported, and insulin therapy carries significant risk due to fasting hypoglycemia in FBS. We report for the first time: (1) glycemic profiles obtained via continuous glucose monitoring (CGM), (2) CGM-guided strategies for cornstarch and nutritional therapy for fasting hypoglycemia and postprandial hyperglycemia, respectively, and (3) placental glucose transporter 2 isoform expression in a pregnant individual with FBS.

Case Report: A 27-year-old woman with FBS presented at 6 weeks gestation for management of fasting hypoglycemia and postprandial hyperglycemia. Cornstarch therapy for fasting hypoglycemia and nutritional therapy for postprandial hyperglycemia were iteratively adjusted across gestation based on CGM-derived glycemic patterns. Pregnancy-specific glycemic targets were successfully achieved, and she delivered a healthy term infant. Glucose transporter 2 isoform was not detected in placental tissue.

Discussion: We report for the first time glycemic patterns across gestation in a pregnant individual with FBS. Glycemic targets were achieved through stepwise optimization of nutritional and cornstarch therapy, both guided by CGM data. Our approach obviated the need for insulin therapy, which carries amplified risk in FBS.

Conclusion: Fasting hypoglycemia and postprandial hyperglycemia can be effectively treated through CGM-guided adjustment of both nutritional and glucose polymer therapies in FBS pregnancy. More broadly, our case highlights a novel application for CGM in the management of uncommon glucose metabolism disorders during pregnancy.