When Weight Loss Surgery Meets Hidden Genetics: Lessons From a Case of Post–Bariatric Surgery Hypoglycemia With ABCC8 and GCK Mutation
Year: 2026
Type: article
Study design: Case Report
Abstract: Background/Objective Post-bariatric hypoglycemia is a recognized complication of Roux-en-Y gastric bypass. We report a case of refractory hypoglycemia following gastric bypass where genetic testing revealed variants that may have contributed to her presentation. Case Report A 26-year-old woman with a body mass index of 48.4 kg/m 2 underwent Roux-en-Y gastric bypass and achieved approximately 63 kg of weight loss. Subsequently, she developed recurrent postprandial hypoglycemia with glucose values in the 2.2–2.8 mmol/L range, with loss of consciousness. Evaluation excluded insulinoma as a cause. Continuous glucose monitoring confirmed delayed postprandial hypoglycemia. Targeted genetic testing using a 120-gene panel identified a heterozygous pathogenic ABCC8 variant c.1332G>T (p.Gln444His) and a GCK variant c.757G>A (p.Val253Ile) of uncertain significance. Sequential pharmacotherapy with acarbose +/- Octreotide 50 mcg sc three times daily + Diazoxide 175 mg three times daily yielded only partial improvement (figure 1). The patient underwent an open Branco-Zorron switch procedure, after which hypoglycemic episodes decreased in frequency and severity on low-dose octreotide at four months of follow-up. Discussion The identification of a genetic susceptibility in this patient suggests that latent genetic susceptibility to hypoglycemia may predispose to severe hypoglycemia when unmasked by the metabolic changes following bariatric surgery. This is especially relevant given that hyperinsulinemia is associated with weight gain. Conclusion This case raises the possibility that preoperative genetic screening for hypoglycemia-associated variants may improve risk PBH stratification in bariatric surgery candidates.
Source: AACE Endocrinology and Diabetes
Institution: SUNY Upstate Medical University
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
OpenAlex ID: W7167472208