Osteogénesis Imperfecta. A propósito de un caso tipo II

Abstract

Osteogenesis Imperfecta (OI) type II is within the group of connective tissue disorders hereditary genetic-origin characterized by bone fragility, multiple fractures, broad long bones and shortened, and a poor bone mineralization. Their frequency is estimated at approximately 1: 55,000 live births, and is the result of mutations of genes which encoding chains of type 1 collagen. The risk of recurrence is around 6% but if both parents were heterozygous, increase to 10-25%. There has also been reported sporadic cases with de novo mutation. The diagnosis is usually made by ultrasound findings in second trimester or previously if the findings are very obvious. Invasive tests are useful especially in cases of family history with mild forms of OI. In our case, we found during ultrasound 20 weeks a remarkable hypomineralization of fetal calvarial, shortening of upper and lower extremities with multiple bone fractures and short costal arches, arched and thoraco-abdominal disproportion. In cases where continued pregnancy more than 60% of newborns die during the first day of life, 80% die in the first month and survival beyond one year is rare. Death can occur prenatally or postnatamente from respiratory failure.