Fibrogenesis imperfecta ossium

Fibrogenesis Imperfecta Ossium

Fibrogenesis imperfecta ossium (FIO) is an extremely uncommon fatal bone disorder of poorly understood etiology. The pathogenesis of FIO is not well known. The fundamental skeletal defect appears to be an abnormality in organic matrix of bone characterized by defective mineralization of the abnormal collagen. FIO clinically manifests in middle-aged adults presenting with fracture and bone pain. Elevated serum alkaline phosphatase is the only and the most consistent biochemical abnormality. Although paraproteinemia is observed in one-third of cases, the pathogenic link to the disease process is unclear. Limited information on FIO and its close resemblance to many metabolic bone disorders leads to delayed or missed diagnoses and management. Prednisolone, bisphosphonates, melphalan and steroids have been tried previously with variable success. Recently, a trial of recombinant growth hormone therapy was found to be effective. Further research focused on the pathogenetic mechanisms of FIO is needed to identify and develop targeted therapeutic options.

Evaluation of laser ablation microtomy for correlative microscopy of hard tissues

Laser ablation machining or microtomy (LAM) is a relatively new approach to producing slide mounted sections of translucent materials. We evaluated the method with a variety of problems from the bone, joint and dental tissues fields where we require thin undecalcified and undistorted sections for correlative light microscopy (LM) and backscattered electron scanning electron microscopy (BSE SEM). All samples were embedded in poly-methylmethacrlate (PMMA) and flat block surfaces had been previously studied by BSE-SEM and confocal scanning light microscopy (CSLM). Most were also studied by X-yay microtomography (XMT). The block surface is stuck to a glass slide with cyanoacrylate adhesive. Setting the section thickness and levelling uses inbuilt optical coherence tomographic imaging. Tight focusing of near-infrared laser radiation in the sectioning plane gives extreme intensities causing photodisruption of material at the focal point. The laser beam is moved by a fast scanner to write a cutting line, which is simultaneously moved by an XY positioning unit to create a sectioning plane. The block is thereby released from the slide, leaving the section stuck to the slide. Light, wet polishing on the finest grade (4000 grit) silicon carbide polishing paper is used to remove a 1-2 μm thick damaged layer at the surface of the section. Sections produced by laser cutting are fine in quality and superior to those produced by mechanical cutting and can be thinner than the 'voxel' in most laboratory X-ray microtomography systems. The present extensive pilot studies have shown that it works to produce samples which we can study by both light and electron microscopy.

Clinical, cellular, microscopic, and ultrastructural studies of a case of fibrogenesis imperfecta ossium

Fibrogenesis imperfecta ossium is a rare disorder of bone usually characterized by marked osteopenia and associated with variable osteoporosis and osteosclerosis, changing over time. Histological examination shows that newly formed collagen is abnormal, lacking birefringence when examined by polarized light. The case presented demonstrates these features and, in addition, a previously undocumented finding of a persistent marked reduction of the serum C3 and C4. Osteoblasts established in culture from a bone biopsy showed abnormal morphology on electron microscopy and increased proliferation when cultured with benzoylbenzoyl-ATP and 1,25-dihydroxyvitamin D, contrasting with findings in normal osteoblasts in culture. A gene microarray study showed marked upregulation of the messenger RNA (mRNA) for G-protein-coupled receptor 128 (GPR 128), an orphan receptor of unknown function and also of osteoprotegerin in the patient's osteoblasts in culture. When normal osteoblasts were cultured with the patient's serum, there was marked upregulation of the mRNA for aquaporin 1. A single pathogenetic factor to account for the features of this disorder has not been defined, but the unique findings described here may facilitate more definitive investigation of the abnormal bone cell function.

Report on a case of fibrogenesis imperfecta ossium and a possible new treatment option

Fibrogenesis imperfecta is an extremely rare acquired progressive bone disorder of unknown etiology. In its course, normal bone architecture is replaced at sites by structurally unsound collagen-deficient tissue resulting in a disorganized bone structure and a skeleton that is radically susceptible to deformity and fracture. Herein, we report the case of a patient who had experienced constant bone pain and several spontaneous fractures since 1997. In 10 years' time with the sole exception of his skull, the disease affected the entire skeleton causing a significant decrease in height and progressive disablement. Laboratory findings included elevation of serum alkaline phosphatase and C-terminal telopeptide of type 1 collagen, with normal serum calcium, phosphate, 25-hydroxy-vitamin-D, and parathyroid hormone concentrations. Monoclonal gammopathy was present with no pathological plasma cells in bone marrow. Radiological and histological results were inconclusive suggesting either osteoporosis, osteomalacia, or Paget's disease and later on osteosclerosis. Treatment administered for the abovementioned conditions has proven to be of no effect. The findings eventually raised the possibility of fibrogenesis imperfecta ossium, which was confirmed by polarized light microscopy as well as transmission electron microscopy. The suggested therapy for the disease is melphalan that could not be initiated due to legal restrictions. Steroid monotherapy also reported to be moderately successful in one case resulted in no improvement. Paraproteinemia had been suggested not only to be a characteristic feature but also a possible etiological factor in this condition. In 2012, plasmapheresis was initiated monthly at the beginning, later on biweekly. In response, the patient's symptoms improved dramatically supporting the abovementioned theory.

Radiographic findings in Waldenström's macroglobulinemia resembling fibrogenesis imperfecta ossium (FIO): a case report

A case of Waldenström's macroglobulinemia with radiographic features of fibrogenesis imperfecta ossium is presented. The case raises the possibility that these radiographic findings might be more common in Waldenström's macroglobulinemia than previously appreciated, and illustrates the need for bone biopsy to establish a definitive diagnosis of fibrogenesis imperfecta ossium.

Osteoporosis associated with neutralizing autoantibodies against osteoprotegerin

Autoantibodies against osteoprotegerin, which block the inhibitory effect of osteoprotegerin on signaling by the receptor activator of nuclear factor (NF)-kappaB (RANK), were identified in a man with celiac disease who presented with severe osteoporosis and high bone turnover. The osteoporosis did not respond to the treatment of his celiac disease but was completely reversed by bisphosphonate therapy. Autoantibodies against osteoprotegerin were detected in three additional patients with celiac disease. Such autoantibodies may be associated with the development of high-turnover osteoporosis, but whether autoantibodies against osteoprotegerin commonly contribute to the pathogenesis of osteoporosis in patients with celiac disease remains to be determined.

Fibrogenesis imperfecta ossium: MR imaging of the axial and appendicular skeleton and correlation with a unique radiographic appearance

We describe a distinctly unusual MR appearance of the cancellous bone never before described in a patient with biopsy-proven fibrogenesis imperfecta ossium.