Type 2 Diabetes Mellitus or Maturity Onset Diabetes in the Young Due to Wolfram Syndrome Gene-1 Mutation-A Perplexing Case.

Background/Objective: Maturity Onset Diabetes in the Young (MODY) is the most common form of monogenic diabetes caused by various single gene mutations. We present a patient with presumed type 2 diabetes mellitus (T2DM), ultimately diagnosed with MODY due to heterozygous Wolfram Syndrome 1 (WFS1) gene mutation. Case Description: Our patient was diagnosed with T2DM at age 22 and treated with oral medications and lifestyle modifications. At age 45, patient's HbA1c was 11.4% (reference <5.7%) on metformin XR 1000 mg twice daily. Additional testing (serum glucose 216 mg/dL [reference: 70-125 mg/dL], C-peptide level 2.18 ng/mL [reference 0.78-5.19 ng/mL], undetectable glutamic acid decarboxylase antibody 65 [GAD-65] [reference: 0.0-5.0 IU/mL], undetectable IgG Islet Cell cytoplasmic antibody [reference: <1:4]) ruled out type 1 diabetes mellitus (T1DM). Due to family history of diabetes and normal body mass index (BMI) 23.2 kg/m Discussion: MODY is a known but uncommon cause of diabetes in young adults. While mutations in HNF1A, GCK, and HNF4A are commonly associated with MODY, rare mutations such as the WFS1 gene mutation should be considered. Our patient's WFS1 mutation (NM_006005.3:c.2026C > T; p.Arg676Cys; heterozygous) has not been reported in literature. Conclusion: Young adults with family history of diabetes and normal BMI should be evaluated for MODY when diagnosed with diabetes. A complete mutation panel for MODY should be done to evaluate for lesser-known mutations such as the WFS1 gene mutation.