Bone Abstracts

Background: Mutations in the ENPP1 gene have been identified in individuals with generalized arterial calcification of infancy (GACI), a life-threatening disorder characterized by calcification in the blood vessels, because of reduced availability of pyrophosphate. We describe a case of GACI due to a novel ENPP1 mutation.Presenting problem: The patient, born at term to non-consanguineous parents, was referred to us at birth with weak femoral pulses for e...

Objectives: Studies indicate that later puberty is associated with lower bone mineral density (BMD) in childhood. Less is known about effects of puberty timing on long-term bone accrual. We examined association between age at puberty and BMD accrual rate from 10 to 25 years.Methods: This was a prospective birth cohort of healthy largely European people born in southwest England in 1991–1992 and regularly follow-up from birth to mean age 25 years. Ag...

Objectives: Osteocytes play a major role in bone metabolism as mechanosensors, key regulators of osteoblast and osteoclast activity and of the mineral homeostasis. Therefore the assessment of osteocytes characteristics is important to understand bone pathology. We propose to study indirectly the osteocytes by performing quantitative backscattered electron imaging to quantify the sectioned osteocyte lacunae density and size in 2D on bone samples.Methods: ...

Objectives: Intravenous cyclical bisphosphonates are widely used to treat children with moderate to severe osteogenesis imperfecta (OI). They increase bone mineral density (BMD), diminish fracture rates and improve mobility. Bisphosphonates are often discontinued when growth is completed. We aimed to determine if the skeletal gains achieved with bisphosphonates persist after their discontinuation in patients with OI.Methods: We assessed patients with OI ...

Background: Lean and bone mass are heritable traits with high phenotypic correlation (rho=0.44), likely reflecting the underlying mechanical and biochemical interactions between tissues.Aim: Estimate the shared heritability (genetic correlation) of both traits in children and identify genetic determinants displaying pleiotropic effects on lean mass and bone mass accrual.Methods: Participants make part of two prospective po...

Introduction: We recently showed that patients with primary Sjögren Syndrome (pSS) have significantly higher bone mineral density (BMD) in the lumbar spine and femoral neck compared with healthy controls. The majority of those patients (69%) were using hydroxychloroquine (HCQ), which may have favourable effects on BMD.Aim: To evaluate whether HCQ modulates human bone cells in vitro.Methods: Osteoblasts were differenti...

Background: Pseudohypoparathyroidism (PHP) is a group of heterogeneous endocrine disorders characterised by hormone resistance, primarily to parathyroid hormone (PTH). The resistance is caused by defects in the GNAS gene, which encodes the Gsα protein that activates the cAMP pathway. PHP patients demonstrate elevated plasma PTH, hypocalcaemia, hyperphosphataemia with normal renal function. PTH resistance can be confirmed by Ellsworth-Howard test (PTH s...

RANKL induced osteoclastogenesis is mediated by several transcription factors such as NF-κB, AP-1 and Nfatc1. We have found that also cysteine proteinases are involved in the signaling pathway downstream RANK. Thus, cystatin C, Z-RLVG-CHN2 (the sequence of which is based upon one of the enzyme inhibitory domains in cystatin C) and the fungal molecule E-64 – inhibit RANKL induced mouse and human osteoclast formation in vitro (Strålberg et ...

Background: Paget’s disease of Bone (PDB) has a strong genetic component and a candidate locus for the disease has been identified on chromosome 14q32, tagged by rs10498635 located within RIN3 (Albagha et al, Nat Genet 2011). RIN3 encodes a protein that acts as a guanine nucleotide exchange factor for Rab5b and Rab31. Here we investigated the candidacy of RIN3 as a predisposing gene for PDB.Methods: We studied expression of RIN3 by quantita...

Objective: Although metabolic syndrome is common in gout patients, recent reports that bone mineral density may actually be reduced (and falls common) in this group have led researchers to hypothesise that osteoporotic fracture may be more common in subjects with gout than in healthy controls. We tested this hypothesis in a national Danish registry.Material and Methods: We identified subjects as new users of allopurinol, a proxy for gout, for the years 1...