Autosomic recessive transmission. D.T.D. gene has been located on chromosome 5.
Most patients have a normal life-span expectancy.
Puberal growth spur does not occur in these patients. Spinal deformities and hip and knee contractures accentuate the apparent dwarfism. Nomocephalic head but typical facial appearance because of the squared jaw, the narrow nasal bridge and the fullness of the circumoral area. It occurs during the first 6 weeks of life after an acute inflammatory process. They can develop severe respiratory insufficiency.