MON-254 Fragility Fracture in a Pediatric Patient with Williams-Beuren Syndrome

Background: Williams-Beuren syndrome (WBS) is a genetic disorder arising from a microdeletion involving the elastin gene. There are several well-defined effects of WBS across multiple organ systems, but less clear is the effect of this syndrome on bone metabolism. While there is literature to suggest that adults with WBS have premature osteopenia and osteoporosis, an increased risk of fracture has not been described in children with WBS . We describe an 11 year old girl with WBS who presented with back pain and was found to have 2 vertebral compression fractures. Clinical Case: The patient was diagnosed with WBS at 1 year of age via genetic testing obtained during a work-up for failure to thrive. She has no prior history of hypercalcemia. At the age of 11 years she complained of severe mid-thoracic back pain lasting several days. There was no history of trauma or cutaneous signs of injury. A plain film revealed compression fracture of 2 thoracic vertebrae; she was then referred to orthopedics and endocrinology. The patient had no history of prior fractures and family denied other episodes of severe pain. Parents reported normal intake and denied any dietary restrictions; there was no family history of bone disease. Her exam was unremarkable and she had normal vital signs, height, weight, and height velocity. Laboratory findings, including calcium, albumin, phosphorus, PTH, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, alkaline phosphatase and urine Ca/Cr ratio, were all within normal limits. The remainder of CMP as well as CBC, ESR, celiac panel, and thyroid function tests were also unremarkable. DEXA was significant for whole body Z-score -1.1, spine -1.6. Following risk-benefit discussion with family, treatment with bisphosphonate therapy was not initiated. Patient was instructed to increase weight-bearing exercise and has had no subsequent fractures. Conclusions: The pathophysiology of hypercalcemia in WBS remains unclear. As it is likely related to a dysregulation of the calcium-PTH axis, these patients may be at risk for abnormal bone turnover and formation. Vitamin D and calcium supplementation are typically not recommended in WBS because these patients remain at risk for hypercalcemia. Therefore, we suggest that these patients may benefit from weight bearing exercise and potentially monitoring of bone density from an earlier age.