Syndactyly in Maturity-onset Diabetes of the Young Type 5 (MODY 5): Expanding the Clinical Phenotype - A Case Report

¹Private Clinic of Endocrinology, Turkey
²Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Aydin Adnan Menderes University, Turkey
³Division of Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, Aydin Adnan Menderes University, Turkey
?Department of Medical Genetics, Faculty of Medicine, Aydin Adnan Menderes University, Turkey

*Corresponding author: Mustafa Unubol, MD, Private Clinic of Endocrinology, Aydin, Turkey, Phone: +90 552 660 3096, E-mail: [email protected]

Received Date: January 07, 2026
Publication Date: February 24, 2026

Citation: Unubol M, et al. (2026). Syndactyly in Maturity-onset Diabetes of the Young Type 5 (MODY 5): Expanding the Clinical Phenotype-A Case
Report. Cases. 5(1):25.

Copyright: Unubol M, et al. © (2026).

ABSTRACT

Maturity-onset diabetes of the young type 5 (MODY 5) is a rare monogenic form of diabetes caused by mutations in the HNF1B gene and is characterized by a multisystem phenotype. Skeletal anomalies are not classically associated with MODY 5. We report a 21-year-old woman with newly diagnosed diabetes initially misclassified as type 1 diabetes who was found to have congenital simple syndactyly of the left hand. She had a strong family history of early-onset diabetes, negative pancreatic autoantibodies, preserved C-peptide levels, and no ketosis at diagnosis. Imaging demonstrated dorsal pancreatic hypoplasia and unilateral renal hypoplasia, and laboratory tests showed hypomagnesemia and hyperuricemia. Genetic analysis identified a heterozygous pathogenic HNF1B variant, confirming the diagnosis of MODY 5. This case suggests a possible and previously unreported association between MODY 5 and syndactyly.

Keywords: MODY 5, HNF1B Mutation, Syndactyly, Monogenic Diabetes, Pancreatic Hypoplasia