Diabetes often develops before the age of 25
Diabetes runs in families from one generation to the next
MODY runs in families because of a change in a single gene which is passed on by affected parents to their children. We call this Autosomal Dominant Inheritance. All children of an affected parent with MODY have a 50% chance of inheriting the affected gene and developing MODY themselves.
Definition from Diabetesgenes website: MODY