Prenatal Diagnosis of Osteogenesis Imperfecta Type III

摘要

A 30-year-old woman in her second pregnancy attendedroutine prenatal visits. Her frst pregnancy was uneventful,and she has a 4-year-old healthy daughter now. The parents were not-consanguineous, and their genetic historiesdid not indicate any abnormality. Nuchal translucency wasnormal in the frst-trimester screening with a present nasalbone. At a routine prenatal visit at 17th gestational weeks,ultrasound revealed: marked shortening (5 percentile) withangulations and bowing of both femurs; the other limb boneswere slightly short (Fig. 1). Fetal foot length was at the 5thpercentile, and the fetal femur/foot ratio was 0.73 (A (p.Gly530Ser)heterozygous mutation for COL1A1 gene coding collagentype 1 alpha chain 1 on 17q21.33 chromosome, whereasCOL1A2 gene and SOX 9 gene found normal. The resultsof the genetic testing with sequencing and ultrasound scanspointed out OI type III. After the genetics consultation, thefamily chose to terminate the pregnancy. At the 23 weeksof gestation, feticide was performed by potassium chloride injection in the umbilical cord and labor was inducedby prostaglandin induction. A 524-g male fetus deliveredthrough vaginal route. The fetal X-ray sonograms showeddeformity of all extremities and ribs due to vaginal deliveryas well as bilateral bowing of the femurs. Post-terminationpathologic fndings showed blue and white cartilaginousnodules on the femur and tibia. Irregularities were observedin the growth plate and trabecular bones of all extremities.Osteoid increase and necrosis in trabecular bone, as well aschanges like fracture healing, were detected (Fig. 2).