An unusual presentation of osteogenesis imperfecta type III

Osteogénesis imperfecta tipo III con presentación inusual

Introduction: osteogenesis imperfecta (OI) is the most common hereditary bone disorder with a global incidence of 1 in 10,000 to 25,000 births. OI is caused by mutations in the genes encoding the chains of collagen type I and is mostly inherited in an autosomal dominant manner. Clinical manifestations vary from asymptomatic with increased propensity to fractures, normal stature and no impact on life expectancy, to high perinatal lethality, severe skeletal deformities, motor disability and very short stature. Objectives: to report a case of an unusual presentation of OI type III in an infant who had in utero fractures, as a diagnostic resource. Case: a full-term infant born via cesarean section, with suspected in utero OI type II, Ballard score: 37 weeks, low weight and multiple fractures and ossification defects (brachycephaly). At 4 months, a higher survival than the expected, he presented greyish sclerae, brachycephaly, large fontanels, generalized bone fragility and bowing of extremities; OI type III was confirmed by exome sequencing. Conclusions: OI diagnosis is based on the clinical and typical features of the disorder. Survival, radiographic findings and molecular genetic testing allow an adequate classification.