Frequency and Characteristics of MODY 1 (HNF4A Mutation) and MODY 5 (HNF1B Mutation): Analysis From the DPV Database.

Objective: To characterize the initial presentation and clinical course of patients with hepatocyte nuclear factor (HNF) 4A‒ and HNF1B‒MODY in a multinational registry.

Design, Setting, And Participants: Within the Diabetes Patienten Verlaufsdokumentation (DPV) registry, 44 patients with HNF4A- and 35 patients with HNF1B-MODY were characterized and compared with patients <20 years old with type 1 diabetes (T1D)/type 2 diabetes (T2D).

Main Outcome Measure: Clinical and laboratory parameters, therapy, metabolic control, and extrapancreatic symptoms in patients with HNF1B-MODY.

Results: Patients with both MODY types were significantly older than patients with T1D at diagnosis (HNF4A, 13.8 years, and HNF1B, 13.5 years, vs T1D, 8.8 years; P < 0.0001). Mean C-peptide at diagnosis was higher for HNF4A-MODY than for T1D (1.8 vs 0.9 ng/mL; P < 0.01); 36.4% of patients with HNF4A-MODY and 65.7% of patients with HNF1B-MODY were treated with insulin, whereas 20.5% and 8.6% received oral antidiabetics only (P < 0.05 and P < 0.01 vs T2D). At the most recent visit, glycated hemoglobin levels were lower in HNF4A- and HNF1B-MODY (mean, 6.5% and 6.1%) than in T1D (7.9%; P < 0.0001). In 40% of patients with HNF1B-MODY, extrapancreatic symptoms were reported. Several clinical predictors previously described to differentiate between MODY and T1D or T2D were revalidated by logistic regression analyses in this cohort.

Conclusion: The DPV registry enabled us to precisely characterize phenotype and treatment in these two rare MODY types. Although phenotype of HNF4A- and HNF1B-MODY showed distinct differences from those of T1D and T2D, 38% of patients were initially misclassified as having T1D or T2D.