Danny DeVito is so short because of a bone condition he has.
Danny Devito has a disease known as Fairbank's disease which is also called multiple epiphyseal dysplasia (MED).
The height of Danny Devito is 4 feet, 10 inches tall and is because of that genetic bone growth disorder.
He is unable to grow any taller because of that bone disease.
Although Danny Devito has played a terrible father on Matilda Danny Devito is actually a kind hearted man and would make a great father in real life.
He's a wonderful actor.