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Background As disease-modifying treatments for spinal muscular atrophy (SMA) are implemented, co-morbidities in adults including osteo-pathologies are increasingly recognised. Guidance for managing such issues is incomplete. We present data on bone health from, to our knowledge, the UK’s largest single-centre adult SMA cohort.Methods Data was prospectively recorded for 100 patients (51% male; 49% female, average age 32), at the National Hospital for Neurology and Neurosurgery from 2022-2025.Results SMA subtypes were SMA3 (55%), SMA2 (44%) and SMA1 (1%).Fracture incidence was 23%, of which 82% affected the lower limb(s). Most fractures (78%) occurred in SMA3 patients who have been ambulant. However, 55% of these patients have since lost ambulation.Bone density scans were recorded in 39% of patients who had fractures (89% of scans occurred post fracture). Bone density scans were recorded in 11.7% of non-fracture patients. Of the overall cohort, 39% were vitamin D deficient/insufficient, and 60% prescribed cholecalciferol.Discussion The high fracture rate is particularly pertinent, given that lower limb fractures can accelerate ambulation loss in SMA3 patients. Consistency in bone-density scanning is lacking and generally reactive to fracture occurrence. Overall, this highlights the importance of bone health considerations in SMA patients.rebecca.johnson131@nhs.net