A case report of maturity-onset diabetes of the young (MODY12) in a Chinese Han patient with a novel ABCC8 gene mutation

Maturity onset diabetes of the young (MODY) is the most common type of monogenic diabetes, characterized by autosomal dominant inheritance, the age of onset is often <25 years old, and the clinical manifestations are atypical. MODY12 is caused by a rare missense mutation of adenosine triphosphate (ATP)-binding cassette transporter subfamily C member 8 (ABCC8) gene and more than 50 ABCC8 variants were associated with MODY12. PATIENT CONCERNS: The patient was a 30-year-old Chinese Han man. He was overweight with a poor control of blood glucose. DIAGNOSES: The patient was diagnosed with MODY12. INTERVENTIONS: The patient was given glimepiride (4 mg/d) with diet and exercise therapy to reduce blood glucose and weight. OUTCOMES: The level of fasting blood glucose and C-peptide was improved after 1 year treatment as well as body weight. LESSONS: A Chinese Han adult with a heterozygous missense mutation c.3976G > A (p.Glu1326Lys) was diagnosed with MODY12, which was the new pathogenic mutation for the disease. This report expands the spectrum of variants causing MODY12 and reduces misdiagnosis.