Efficacy of denosumab therapy for neurofibromatosis type 1 with osteoporosis and history of fractures: a case report

BACKGROUND: The natural history and pathogenesis of the skeletal abnormalities found in neurofibromatosis type 1 (NF1) are poorly understood, and the therapeutic options for these manifestations remain limited. This report first describes the clinical outcomes of denosumab treatment for a patient with NF1 suffering from osteoporosis. METHODS: We enrolled a patient with NF1 under denosumab treatment for osteoporosis, prior fractures, and no improvement in bone mineral density (BMD) over 3 years of alendronate therapy. BMD was monitored by dual-energy X-ray absorptiometry. Tested laboratory data included bone-specific alkaline phosphatase, urinary type I collagen amino-terminal telopeptide, tartrate-resistant acid phosphatase 5b, 1-alpha, 25-dihydroxyvitamin D(3), and parathyroid hormone. BMD and laboratory data were evaluated before, between 2 and 4 months, and at 6, 12, 18, and 24 months of treatment. CASE PRESENTATION: During 2 years of denosumab therapy for osteoporosis in a 58-year-old female NF1 patient with prior fractures, BMD increased by 6.5% in the lumbar spine and 10.6% in the total hips, and bone turnover markers were notably improved. No fractures occurred during the latter half of treatment. CONCLUSION: Denosumab represents an effective treatment option for osteoporosis in NF1 patients.