SUN-362 Bone Involvement in Adult Patients Affected with Ehlers-Danlos Syndromes

INTRODUCTION: The Ehlers-Danlos syndrome (EDS) is characterized by abnormalities of the connective tissue leading to ligamentous laxity and skin and tissue fragility, bone involvement is an emerging manifestation. We evaluated the bone metabolism, bone mineral density (BMD) and bone quality (measured by trabecular bone score, TBS), and the prevalence of clinical fractures and morphometric vertebral fractures (mVFx) in a large group of adult EDS patients. METHODS: Two-hundred and sixty-six consecutive Caucasian patients, aged ≥18 years (38.3±11.8) (190 females, 76 males) 58% with classical, 34.9% with hypermobility, 4.5% with vascular and 4.8% undefined EDS were enrolled. We had genetic information of 117 patients (74 patients showed no mutations, 2 COL2 mutations, 8 COL3 mutation, 28 COL5 mutations and 5 other genes mutations). In all subjects’ calcium-phosphorous metabolism, bone turnover, BMD at the lumbar spine (LS) and femur (femoral neck, FN and total femur, FT) and radius and TBS by dual-energy X-ray absorptiometry were assessed. Moreover, we evaluated the history of clinical fragility and the mVFx presence by spine radiograph. RESULTS: The 20.6% of patients showed a Z-score BMD ≤-2.0, the 29.8% ≥1 mVFx and the 24.5% ≥1 clinical fractures. Male patients showed a higher prevalence of reduced BMD (31.9 vs 15.6%; p=0.007) and mVFx (41.4% vs 24.8%; p=0.026). Patients with ≥1 mVFx were older (43.2±12 vs 35.6±12; p=0.0001), showed a lower TBS z-score (-1.4±1.7 vs -0.8±1.2; p=0.013) and lower phosphate levels (3.3±0.6 vs 3.5±0.5; p=0.032) with an higher prevalence of hypophosphatemia (24.5% vs 8.8%; p=0.014). No difference was found in prevalence of EDS subtypes or gene mutations. In EDS patients, the VFx presence was significantly associated with TBS and age, even after adjusting for sex and hypophosphatemia. CONCLUSIONS: EDS patients have reduced BMD and bone quality (as measured by TBS) and increased prevalence of clinical and mVFx associated with age and TBS.