When Weight Loss Surgery Meets Hidden Genetics: Lessons From a Case of Post–Bariatric Surgery Hypoglycemia With ABCC8 and GCK Mutation
- 1Division of Endocrinology, Diabetes, and Metabolism, State University of New York (SUNY) Upstate Medical University, Syracuse, New York
- 2Division of Bariatric Surgery, SUNY Upstate Medical University, Syracuse, New York
Abstract
Background/Objective: Postbariatric 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/m2 underwent Roux-en-Y gastric bypass and achieved ∼63 kg of weight loss. Subsequently, she developed recurrent postprandial hypoglycemia with glucose values in the 2.2 to 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 μg sc 3 times daily + diazoxide 175 mg 3 times daily yielded only partial improvement (Fig. 1). The patient underwent an open Branco-Zorron switch procedure, after which hypoglycemic episodes decreased in frequency and severity on low-dose octreotide at 4 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 post-bariatric hypoglycemia stratification in bariatric surgery candidates.
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BibTeX
@article{adeniran2026when,
title = {{When Weight Loss Surgery Meets Hidden Genetics: Lessons From a Case of Post–Bariatric Surgery Hypoglycemia With ABCC8 and GCK Mutation}},
author = {Uchechi Adeniran and Ibrahim H. Topkaya and Timothy Shope and Melih Kasap and Tuncay Delibasi and Malek El Muayed},
journal = {AACE Endocrinology and Diabetes},
year = {2026},
month = jul,
doi = {10.1016/j.aed.2026.06.012},
url = {https://doi.org/10.1016/j.aed.2026.06.012},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - When Weight Loss Surgery Meets Hidden Genetics: Lessons From a Case of Post–Bariatric Surgery Hypoglycemia With ABCC8 and GCK Mutation
AU - Uchechi Adeniran
AU - Ibrahim H. Topkaya
AU - Timothy Shope
AU - Melih Kasap
AU - Tuncay Delibasi
AU - Malek El Muayed
PY - 2026
DA - 2026/07/06
JO - AACE Endocrinology and Diabetes
DO - 10.1016/j.aed.2026.06.012
UR - https://doi.org/10.1016/j.aed.2026.06.012
AB - Background/Objective: Postbariatric 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/m2 underwent Roux-en-Y gastric bypass and achieved ∼63 kg of weight loss. Subsequently, she developed recurrent postprandial hypoglycemia with glucose values in the 2.2 to 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 μg sc 3 times daily + diazoxide 175 mg 3 times daily yielded only partial improvement (Fig. 1). The patient underwent an open Branco-Zorron switch procedure, after which hypoglycemic episodes decreased in frequency and severity on low-dose octreotide at 4 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 post-bariatric hypoglycemia stratification in bariatric surgery candidates.
SN - 3050-9157
ER -