Bone Abstracts

Background: Bone marrow (BM) adiposity is inversely related to bone mineral density and increases with ageing and menopause. We previously observed that the variation in BM fat fraction was more pronounced in premenopausal women compared to men and postmenopausal women. We hypothesized that the variation in BM fat fraction in premenopausal women is associated with hormonal variations during the menstrual cycle.Objective: To investigate the dynamic change...

Bone strength is influenced by cortical thickness, area, mass and porosity, all of which contribute to nonvertebral fracture risk. Cortical porosity is one parameter of structural decay associated with bone fragility. This is caused by unbalanced and accelerated remodelling of Haversian units which enlarge, coalesce and fragment the cortex. Antiresorptive therapies will limit progression of cortical porosity; reducing existing porosity would be a goal for those already at incr...

Dysosteosclerosis (DSS) is the rare osteopetrosis (OPT) distinguished by metaphyseal osteosclerosis with relative radiolucency of widened diaphyses and platyspondyly. In 2012, mutations in the SLC29A3 gene were discovered to cause DSS.Here, we report a new case of DSS presenting with severe anemia and having a unique homozygous mutation in SLC29A3.Our patient was the 3rd child of consanguineous Turkish parents. She present...

Background: Systemic alterations in Runx2 expression have been shown to affect flat and long bone formation differently: Inactivating mutations cause low-turnover bone disease and patent fontanels in cleidocranial dysplasia, while overexpressing mutations cause metaphyseal dysplasia with maxillary hypoplasia and brachydactyly. The two conditions have inverse skeletal phenotypes. We know of no descriptions of these disorders in a patient without duplications or mutations of Run...

Objectives: In XLH, FGF23-mediated hypophosphatemia leads to defective bone mineralization and rickets. Investigational product KRN23 binds FGF23 and inhibits its activity. The objective of this Phase 2 study was to evaluate the safety and efficacy of KRN23 in 52 children with XLH (ages 5–12 years, ≤Tanner 2).Methods: Patients were randomized to receive KRN23 biweekly (Q2W) or monthly (Q4W) by SC injection. KRN23 dose was titrated (maximum 2 m...

Objectives: In XLH, musculoskeletal outcomes of current treatment with oral phosphate (Pi)/active vitamin D are suboptimal for many patients. In a Phase 2, open-label study, we tested the hypothesis that KRN23 improves rickets and functional outcomes in XLH children.Methods: Fifty-two children with XLH (ages 5–12 years at baseline) received KRN23 subcutaneously biweekly (Q2W) or monthly (Q4W). At study entry, most participants had received oral Pi/a...

Although Vitamin D deficiency is the most common form of rickets worldwide, when there is a failure to respond to cholecalciferol, inborn errors of vitamin D metabolism should be considered. We describe two unrelated individuals who presented with early onset rickets characterised by reduced serum levels of 25(OH)D and 1,25(OH)2D, and a deficient response to Vitamin D2/D3 and calcitriol. Case 1: A Caucasian Australian girl with non-consanguineous parents ...

Introduction: Perthes disease (PD), idiopathic femoral head avascular necrosis, often results in deformity. The underlying cause is unclear and long-term function is directly related to the roundness of femoral head. Current treatment include mechanical treatments and various surgical procedures, which are therapeutic but can’t prevent collapse. A multicentre, prospective, randomised controlled trial of 12 months zoledronic acid (ZA) in children with PD was conducted. We ...

Objective: We evaluated the long-term efficacy of burosumab, a monoclonal antibody against FGF23, in a Phase 2 Study (NCT02163577) in children with XLH.Methods: Fifty-two children with XLH (5-12 years-old, Tanner ≤ 2) were randomized 1:1 to receive subcutaneous burosumab Q2W or Q4W for 64 weeks. Doses were titrated up to 2 mg/kg/dose targeting serum phosphorus levels within 1.1–1.6 mmol/l. All subjects entered the long-term extension at Week 6...

Objectives: Asfotase alfa (AA), an enzyme replacement therapy, is the only approved treatment for pediatric-onset hypophosphatasia (HPP). We evaluated the safety profile of AA from the clinical trial program spanning pediatric and adult patients.Methods: Safety data were pooled from 4 open-label, multicenter studies in children aged ≤3 years (study 002/003 [NCT00744042/NCT01205152]; n=11) and ≤5 years (study 010-10 [NCT01176266]; <em...