Bone Abstracts

Objective: This study aimed to evaluate the efficacy of the treatment with pamidronate disodium (PD) with respect to the increase of bone mineral density (BMD) in patients with osteogenesis imperfecta (OI).Patients and methods: We evaluated nine patients (six boys) with OI (four with type III, four with type IV, one with type I) treated with PD from 4.68 to 7.92 years (mean±S.D.: 6.75±1.38 years). Intravenous PD was administered ...

Infantile spinal muscular atrophy X-linked 2 (SMAX2) is a rare form of spinal muscular atrophy manifesting in severe hypotonia, areflexia, arthrogryposis, facial weakness and cryptorchidism, as frequently accompanied by bone fractures.We present a boy patient with SMAX2 who presented typical symptoms from birth, as preceded by reduced fetal movements in the second and third trimester of pregnancy. In the first days of life the patient was found to have s...

Background: Mutations in the PLS3 gene, encoding plastin 3, cause X-linked osteoporosis. Osteoporosis is characterized by low bone mineral density (BMD) and increased susceptibility to fractures. Here we describe a 7-year-old boy with osteoporosis due to a novel PLS3 deletion.Presenting problem: The patient, born to non-consanguineous parents, had a history of one low-energy long-bone fracture, three vertebral fractures (T5, T6 T8) and kyphosis. DXA scan...

Osteogenesis imperfecta (OI) type V is caused by a unique dominant mutation (c.−14C>T) in IFITM5, which encodes BRIL, a transmembrane ifitm-like protein most strongly expressed in osteoblasts, while type VI OI is caused by recessive null mutations in SERPINF1, encoding pigment epithelium-derived factor (PEDF). We identified a 25-year-old woman with severe OI, whose dermal fibroblasts and cultured osteoblasts displayed minimal secretion of PEDF, but ...

We report a male child presenting with antenatally diagnosed bilateral talipes equinovarus, short stature, bilateral cryptorchidism and poor weight gain; born at 39 weeks gestation (birth weight 2.56 kg) to non-consanguineous Caucasian parents. Facial dysmorphism included a prominent forehead, brachycephaly, shallow orbits, a high anterior hairline, a narrow nasal bridge and small mouth with a thin upper lip. He had white sclera and was short for height (−4.4 SDS) with a...

Background: Primary de Toni-Debré-Fanconi syndrome is a metabolic disorder characterized by hypophosphatemic rickets or osteomalacia, renal tubular acidosis, renal glycosuria, generalized aminoaciduria. It is a non-FGF23-mediated hypophosphatemic disorder, with primary defect in proximal tubular dysfunction. The orthopaedic sequela of this rare disorder in the literature is scarce.Presenting problem: We present a clinical case of a 10-year-old femal...

Introduction: Osteogenesis imperfecta (OI) is a genetically heterogeneous disorder characterized by bone fragility. OI type V, with autosomal dominant inheritance, is characterized by ossification of the forearm interosseus membrane, radiodense metaphyseal bands, propensity for hyperplastic callus formation, and mesh-like lamellation on bone histology. Type V OI probands are reported to have white sclerae and normal teeth. Recent reports identified the cause of type V OI as a ...

Using a CyPB-null mouse model, we previously demonstrated delayed folding, abnormal post-translational modification and altered crosslinking of type I collagen synthesized by osteoblasts. However, intracellular folding of collagen molecules was further delayed by CsA treatment of CyPB-null cells, suggesting involvement of additional PPIases in collagen folding. Since studies of CyPA functions in osteoblasts have not been reported, we investigated the role of this cytoplasmic P...

Deficiency of Cyclophilin B (CyPB) causes recessively inherited Type IX osteogenesis imperfecta, a moderately severe to lethal bone dysplasia. CyPB, encoded by PPIB, is an ER-resident peptidyl-prolyl cis-trans isomerase (PPIase) that catalyzes the rate-limiting step in collagen folding, and also functions as a component of the collagen prolyl 3-hydroxylation complex. We previously demonstrated in a Ppib−/− mouse model that CyPB PPIase activity r...

Introduction: Recessive osteogenesis imperfecta (OI) is caused by mutations in genes encoding proteins involved in post-translational interactions with type I collagen. Types VII–IX OI involve defects in the collagen prolyl 3-hydroxylation complex, which modifies α1(I)Pro986. PPIB encodes CyPB, a complex component with PPIase activity and the major isomerase facilitating collagen folding. We investigated the role of CyPB in collagen post-translational modifications a...