A stillborn male fetus is brought to autopsy for evaluation. The fetus was delivered at approximately 36 weeks gestation to a 26-year-old woman, gravida 5 para 1 aborta 3, who received no prenatal care. The mother came to the hospital in active labor; an ultrasound on admission revealed no fetal cardiac activity. She had an uncomplicated vaginal delivery of the stillborn fetus, weight 2.2 kg (4.9 lb). The mother had a prior healthy female infant via normal vaginal delivery at 39 weeks gestation and 3 subsequent elective terminations of pregnancy. She does not use tobacco, alcohol, or illicit drugs. The fetus has short, bent extremities. X-ray reveals multiple limb fractures and a hypoplastic thoracic cavity. Which of the following is the most likely cause of these fetal abnormalities?

Question

A stillborn male fetus is brought to autopsy for evaluation.  The fetus was delivered at approximately 36 weeks gestation to a 26-year-old woman, gravida 5 para 1 aborta 3, who received no prenatal care.  The mother came to the hospital in active labor; an ultrasound on admission revealed no fetal cardiac activity.  She had an uncomplicated vaginal delivery of the stillborn fetus, weight 2.2 kg (4.9 lb).  The mother had a prior healthy female infant via normal vaginal delivery at 39 weeks gestation and 3 subsequent elective terminations of pregnancy.  She does not use tobacco, alcohol, or illicit drugs.  The fetus has short, bent extremities.  X-ray reveals multiple limb fractures and a hypoplastic thoracic cavity.  Which of the following is the most likely cause of these fetal abnormalities?

Quizplus · Accepted Answer

11ec25c8_da57_6451_bc81_fd7091119f85_MD0003_00 An intrauterine fetal demise associated with growth restriction, multiple limb fractures, and a hypoplastic thoracic cavity is consistent with type II osteogenesis imperfecta (OI). Type II OI is an autosomal dominant disorder due to defective type 1 collagen synthesis that results in decreased bone density and increased skeletal fragility. This disorder has a varying spectrum of severity, from mild (type I), moderate (types III-IX), to fatal perinatal (type II) disease. Type II OI is typically diagnosed via antenatal ultrasound findings of multiple fractures, a shortened femur, a hypoplastic thoracic cage, and growth restriction. Type II OI is lethal; most fetuses either die in utero, during delivery due to trauma, or shortly after delivery due to pulmonary hypoplasia (a complication of thoracic cavity hypoplasia). Infants who survive delivery are given supportive care. (Choice A) Achondroplasia is a non-lethal autosomal dominant bone dysplasia that presents with macrocephaly, frontal bossing, midface hypoplasia, genu varum, and limb shortening. Achondroplasia (Choice B) Amniotic band sequence is associated with limb defects (eg, amputation, hand defects, clubfoot), craniofacial defects, and/or abdominal wall defects. It does not present with bone fractures and is typically not lethal. (Choice C) Birth trauma is most frequently associated with fetal macrosomia and shoulder dystocia. Birth trauma is typically due to shoulder dystocia maneuvers that can result in an isolated fracture (eg, clavicle, humerus). (Choice E) Paget disease is a bone metabolism disorder due to defective osteoclast activity. This disease typically has an adult, rather than in utero, onset and presents with headaches, hearing loss, spinal stenosis, and osteosarcoma. (Choice F) Potter sequence is a lethal fetal anomaly that presents with pulmonary hypoplasia, limb deformities (eg, clubfoot, hip dislocation), and oligohydramnios. The sequence is most commonly due to urinary tract abnormalities (eg, bilateral renal agenesis, polycystic kidney disease). There is no association with limb fractures. (Choice G) Maternal vitamin D deficiency is associated with fetal growth restriction, not with fractures or intrauterine fetal demise. Educational objective: Osteogenesis imperfecta is an autosomal dominant disorder characterized by mutations in type 1 collagen. Type II osteogenesis imperfecta, the most severe form, is associated with multiple fetal fractures and with intrauterine fetal demise. Other findings include limb deformities, fetal growth restriction, and a hypoplastic thoracic cavity. References: Classification of osteogenesis imperfecta. (http://www.ncbi.nlm.nih.gov/pubmed/26208476)

A Stillborn Male Fetus Is Brought to Autopsy for Evaluation