SAT-728 - Coexistence of Osteogenesis Imperfecta and Primary Osteoporosis in A Postmenopausal Patient

Introduction: Osteogenesis imperfecta (OI) is a rare genetic connective tissue disorder caused by mutations in type I collagen genes (most commonly COL1A1 or COL1A2), resulting in impaired bone matrix formation and lifelong low bone mineral density (BMD). Clinical severity varies by subtype and may include recurrent fractures, skeletal deformities, and extraskeletal manifestations. Comparatively, primary osteoporosis is an age- or menopause-related process characterized by progressive bone loss. In rare cases, OI may present with low BMD and can be further exacerbated by menopause-related bone loss in primary osteoporosis, increasing skeletal fragility. Here we present a case of a postmenopausal patient diagnosed with osteogenesis imperfecta type IV during the workup of osteoporosis.
Clinical case: A 54-year-old Caucasian female with a history of several low-trauma childhood fractures, dental abnormalities, and last menstrual period at the age of 51 presented to Endocrinology clinic for evaluation of osteoporosis. Patient reported that genetic testing for bone disorders done several years ago was negative with no records found, and alendronate use in her 30s was self-discontinued. Family history was positive for developmental hip and wrist abnormalities in her two sons. DEXA scan at age 49 (no treatment initiated) revealed osteoporosis at multiple sites with the lowest BMD & T score at lumbar spine with L1-L4 0.833 and –2.9. Repeat DEXA scan at age 53 showed worsening results with lowest scores at L1-L4 0.714 and -3.9. For primary osteoporosis management after the 2nd DEXA scan, the PCP initiated alendronate therapy for 8 months. Upon referral to Endocrinology, due to worsening DEXA scan, normal secondary workup, and significant personal and family history, genetic testing was pursued, which showed a pathogenic variant in the COL1A2 gene consistent with osteogenesis imperfecta type 4. The patient was switched from alendronate to the sclerostin inhibitor romosozumab due to its demonstrated success for management of severe osteoporosis, and patient has recently completed the 12-month treatment course in Jan 2026. We plan to initiate an antiresorptive regimen soon to hopefully preserve BMD gain, as well as obtain a DEXA scan to evaluate romosozumab efficacy in February 2026.

Conclusion: This case demonstrates the importance of considering osteogenesis imperfecta in patients with low BMD and a history of childhood fractures, as the superimposition of age-related bone loss on the impaired collagen formation in OI increases fracture risk, especially after menopause. In addition, while current first line pharmacologic management of both OI and postmenopausal osteoporosis is bisphosphonates, sclerostin inhibitor therapy has shown evidence-based results in the treatment for severe osteoporosis, with therapy response evaluation for this case pending February 2026.

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