Osteogenesis imperfecta (OI) is a hereditary disease characterized by bone fragility and short stature. The molecular reasons are mutations in COL1A1 or COL1A2. Inheritance follows an autosomal dominant pattern, sporadic mosaics and recessive forms are described. The incidence is described as 1:20,000 life births. The clinical spectrum represents a continuum ranging from perinatal lethality (type II) to nearly asymptomatic individuals (type I) with occasional fractures and normal stature. Besides the pathological fractures due to minor trauma the clinical presentation may also include bone deformity, scoliosis, growth retardation, early hearing loss, blue sclera, reduced muscle tone, mitral valve prolapse and platelet dysfunction. OI type III is the most severe form in children surviving the neonatal period and leads to extreme short stature. Patients with mild to moderate bone deformities and variable short stature are classified as OI type IV.