Medicine Diabetes Mellitus 386c85f6 HNF- 1b gene defect is seen in? A MODY2 B MODY3 C MODY4 D MODY5 High-Yield Explanation HNF- 1b gene is involved in pathogenesis of MODY5. HNF- 1a gene is involved in pathogenesis of MODY 3. Most common type of MODY is MODY 3.