Very few patients reach adulthood. Children sustain multiple fractures and progressive kyphoscoliosis. The skull is soft and deformed. Most patients succumb to cardiorespiratory complications in infancy or childhood. Type IV osteogenesis imperfecta is characterized by osteoporosis leading to bone fragility of variable severity.
Inheritance is autosomal dominant.
The sclerae may be bluish at birth, but this becomes less prominent as the patient ages. Because of variable severity, some patients sustain their first fractures in infancy, while others sustain their first fractures as adults. There are variable degrees of bow legs, scoliosis and short stature. Many patients show spontaneous improvement with age. This form of OI may be occult.