Abstract
Maturity-Onset Diabetes of the Young (MODY)encompasses genetic disorders caused by mutations in single genes associated with beta cell dysfunction, constituting 1-6% of all diabetes cases. Mutations in ATP binding cassette transporter subfamily C member 8 (ABCC8) causes MODY 12 which accounts for 1% among MODY cases. It can present in childhood, adolescence or adulthood. Despite growing awareness, accurate MODY diagnosis remains challenging, often leading to misclassification as type 1 or type 2 diabetes. Correct identification is crucial for tailored treatment and implications for family members.
The coexistence of MODY and autoimmune related diabetes is a very rare phenomenon with only a handful of cases reported. We describe a unique case where the index patient was initially diagnosed with type 1 diabetes at age 8 due to antibody positivity, leading to insulin treatment. After 15 years, he presented with evidence of all microvascular complications. Interestingly, his brother also developed diabetes at age of 14 years but with out antibody positivity. Due to a strong family history, both siblings underwent genetic testing, revealing a heterozygous mutation in the ABCC8 gene (C.4799630 G>A; P-Arg 1600His).