Osteoporotic vertebral fractures during pregnancy: Be aware of a potential underlying genetic cause

Context: Although thebabygrowingin its mother'swombneeds calcium for skeletal development, osteoporosis and fractures very rarely occur during pregnancy. Case Presentation: A 27-year-old woman in the seventh month of her first pregnancy contracted midthoracic back pain after liftinganobject. Thepainwasattributed to her pregnancy, but itremained postpartum. Her past medical history was uneventful, except for severely reduced vision of her left eye since birth. Family history revealed that her maternal grandmother had postmenopausal osteoporosis and her half-brother had three fractures during childhood after minor trauma. Her height was 1.58 m; she had no blue sclerae or joint hyperlaxity. Laboratory examination including serum calcium, phosphate, alkalinephosphatase,creatinine,-carboxyterminal cross-linking telopeptide oftypeI collagen, 25-hydroxyvitamin D, and TSH was normal. Multiple thoracic vertebral fractures were diagnosed on x-ray examination, and dual-energy x-ray absorptiometry scanning showed severe osteoporosis (Zscores: L2-L4, -5.6 SD; femur neck, -3.9 SD). DNA analyses revealed two compound heterozygous miss ensemutations in LRP5.Thepatient'smother carried one of the LRP5 mutations and was diagnosed with osteoporosis. Her half-brother, treated with cabergoline for a microprolactinoma, also had osteoporosis of the lumbar spine on dual-energy x-ray absorptiometry and carried the same LRP5 mutation. The patient was treated with risedronate for 2.5 years. Bone mineral density and back pain improved. She stopped bisphosphonate use 6 months before planning a second pregnancy. Conclusion: Our patient was diagnosed with osteoporosis pseudoglioma syndrome/familial exudative vitreoretinopathy. Potential underlying genetic causes should be considered in pregnancyassociated osteoporosis with implications for patients and relatives. More studies regarding osteoporosis treatment preceding conception are desirable. Copyright

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