SNX10 gene mutation leading to osteopetrosis with dysfunctional osteoclasts

Acknowledgements We sincerely thank the patients and family members who participated in this study. We would also like to thank Stefan Esher, Umeå University, for help with genealogy, and Anna Westerlund for excellent technical assistance. This work was supported by grants from the FOU, at the Umeå university hospital, and the Medical Faculty at Umeå University. The work at University of Gothenburg was supported by grants from The Swedish Research Council, the Swedish Rheumatism Association, the Royal 80-Year Fund of King Gustav V, ALF/LUA research grant from Sahlgrenska University Hospital in Gothenburg and the Lundberg Foundation. The work at the University of Gothenburg and the University of Aberdeen was supported by Euroclast, a Marie Curie FP7-People-2013-ITN: # 607446.Peer reviewedPublisher PD

La coxartrosis en los pacientes con osteopetrosis: su tratamiento quirúrgico

Se presentan un caso de osteopetrosis en un paciente de 22 años de edad que consultó por dolor en la cadera izquierda, siendo diagnosticado de coxartrosis izquierda secundaria a la osteopetrosis. Fue tratado inicialmente de forma quirúrgica realizándosele una osteotomía de la cadera afectada. Varios años después, tras la reaparición del dolor se procedió a la implantación de una prótesis total de cadera que evolucionó satisfactoriamente.A case of osteopetrosis in a 22-year-old patient who consulted by pain in the left hip is presented. He was diagnosed of degenerative osteoarthritis of the left hip secondary to osteopetrosis. Initially, it was treated surgically by an osteotomy of the proximal femur. Several years later\ after the pain reappearance, the authors treated the patient by a total hip arthroplasty with satisfactory outcome

Serum creatine kinase isoenzymes in children with osteogenesis imperfecta

This study evaluates serum creatine kinase isoenzyme activity in children with osteogenesis imperfecta to determine its usefulness as a biochemical marker during treatment with bisphosphonate. The changes of creatine kinase (CK) isoenzyme activity during and after discontinuation therapy were observed. These results could be useful in addressing over-treatment risk prevention. Introduction The brain isoenzyme of creatine kinase (CKbb) is highly expressed in mature osteoclasts during osteoclastogenesis, thus plays an important role in bone resorption. We previously identified high serum CKbb levels in 18 children with osteogenesis imperfect (OI) type 1 treated for 1 year with bisphosphonate (neridronate). In the present study, serum CK isoenzymes were evaluated in the same children with continuous versus discontinued neridronate treatment over a further 2-year follow-up period. Methods This study included 18 children with OI type 1, 12 with continued (group A) and 6 with ceased (group B) neridronate treatment. Auxological data, serum biochemical markers of bone metabolism, bone mineral density z-score, and serum total CK and isoenzyme activities were determined in both groups. Results Serum CKbb was progressively and significantly increased in group A (p < 0.004) but rapidly decreased to undetectable levels in group B. In both groups, the cardiac muscle creatine kinase isoenzyme (CKmb) showed a marked decrease, while serum C-terminal telopeptide (CTx) levels were almost unchanged. Conclusions This study provides evidence of the cumulative effect of neridronate administration in increasing serum CKbb levels and the reversible effect after its discontinuation. This approach could be employed for verifying the usefulness of serum CKbb as a biochemical marker in patients receiving prolonged bisphosphonate treatment. Moreover, the decreased serum CKmb levels suggest a systemic effect of these drugs

The unbearable lightness of bone marrow homeostasis

The anatomical and functional dimensions of bone marrow topography have been at the forefront of modern bone and immunological research for many years and remain a source of complexity and perplexity due to the multitude of microhabitats within this microenvironment. In fact, research has uncovered fascinating functional aspects of bone marrow residents, and the bone marrow niche has been identified as the foremost reservoir of a variety of cells including hematopoietic, skeletal and endothelial stem/progenitor cells. The physical interactions of the marrow residents, combined with the release of cytokines and growth factors, organize well-defined operative compartments, which preserve bone and immune cell homeostasis. In a simplistic view, both the hematopoietic and bone marrow stromal (mesenchymal) stem/progenitor cell populations dwell at the interface between the endosteum and the bone marrow area (endosteal niche) and in the perivascular space (vascular niche). Indeed, the tantalizing hypothesis of bone marrow regulatory dependency on these niches is supported by current research insofar as the increase in the number of osteoblasts results in a concomitant increase in the hematopoietic population, indicating that the osteoblasts and the endosteal niche are key components of HSC maintenance. On the other hand, impaired function of the vascular niche compromises the endosteal niche's ability to support hematopoiesis. These fascinating discoveries indicate that there are strong ties between bone marrow inhabitants within the confines of the bone marrow itself. When these ties fail, niche-niche communication suffers and results in reduced bone formation, enfeebled hematopoiesis and unrestrained HSC migration through blood circulation. This study focused on the extraordinary homeostatic equilibrium and function of both bone and immune cells within the spatially defined microenvironment of bone marrow. But how important is the anatomically outlined scenery in which the bone marrow entity supports and hosts the hematopoietic elements

Mechanical and material properties of cortical and trabecular bone from cannabinoid receptor-1-null (Cnr1-/-) mice

Funding ABK was funded by a studentship from the University of Aberdeen, Institute of Medical Sciences, and the Overseas Research Students Awards Scheme Acknowledgments We are grateful to Dr J.S. Gregory for assistance with Image J and Mr K. Mackenzie for assistance with Micro-CT analysis.Peer reviewedPostprin

Investigations on Congenital and Induced Osteopetrosis

Osteopetrosis, or marble bone disease, is a disturbance of skeletal development in which the rate of bone resorption fails to keep pace with the rate of bone formation. Bone matrix accumulates excessively throughout the skeletal system, causing damage to neighboring tissues--particularly the dental, hematopoietic and nervous tissues. The line of investigation on osteopetrosis which has led to the current point of view that the thyroid gland represents the primary side of the disturbance was initiated soon after an experimental animal became available

Osteopetroses, emphasizing potential approaches to treatment

Osteopetroses are a heterogeneous group of rare genetic bone diseases sharing the common hallmarks of reduced osteoclast activity, increased bone mass and high bone fragility. Osteoclasts are bone resorbing cells that contribute to bone growth and renewal through the erosion of the mineralized matrix. Alongside the bone forming activity by osteoblasts, osteoclasts allow the skeleton to grow harmonically and maintain a healthy balance between bone resorption and formation. Osteoclast impairment in osteopetroses prevents bone renewal and deteriorates bone quality, causing atraumatic fractures. Osteopetroses vary in severity and are caused by mutations in a variety of genes involved in bone resorption or in osteoclastogenesis. Frequent signs and symptoms include osteosclerosis, deformity, dwarfism and narrowing of the bony canals, including the nerve foramina, leading to hematological and neural failures. The disease is autosomal, with only one extremely rare form associated so far to the X-chromosome, and can have either recessive or dominant inheritance. Recessive ostepetroses are generally lethal in infancy or childhood, with a few milder forms clinically denominated intermediate osteopetroses. Dominant osteopetrosis is so far associated only with mutations in the CLCN7 gene and, although described as a benign form, it can be severely debilitating, although not at the same level as recessive forms, and can rarely result in reduced life expectancy. Severe osteopetroses due to osteoclast autonomous defects can be treated by Hematopoietic Stem Cell Transplant (HSCT), but those due to deficiency of the pro-osteoclastogenic cytokine, RANKL, are not suitable for this procedure. Likewise, it is unclear as to whether HSCT, which has high intrinsic risks, results in clinical improvement in autosomal dominant osteopetrosis. Therefore, there is an unmet medical need to identify new therapies and studies are currently in progress to test gene and cell therapies, small interfering RNA approach and novel pharmacologic treatments

Volume Five Subject Index

Subject index for MCV/Q, Medical College of Virginia Quarterly, Volume Five

Retardo de desenvolvimento associado à Osteopetrose

Osteopetrosis is a rare genetic disease, caracterized by marked radiodensity of the bones throughout the skeleton. Heterogenous clinical, biochemical, and histological features suggest that the disease is multigenic. We will describe a case with severe growth delay and bone fractures. EDO, 19 years and 9 months old, that came to us due to a skeleton alteration and growth failure. His puberty begun at 18 years old, with slow progress. Six months ago, after falling from his own high he broke his right forearm. He was 141,5 em high and weighted 38,5 kg, with bone age at 13 years and 6 months. The skeleton examination showed hyperdensity of the bones with typical alteration observed in osteopetrosis with signs of fractures in ulna and femur both on the right. The bone density were on lumbar spine and femural neck respectively 10,65 and 15,55 SD higher than the average for his own age. The dosages of the hormones showed total testosterone levels below normal for chronological age (245 ng/dl); normal basal and stimulated gonadotropins levels, GH responsive to hypoglycemia and insulin-like growth factor-I (IGF-I) level low for puberal stage. The plasma calcium (Ca), phosphorus (P), alcaline phosphatase (FA) and intact parathormone (PTH) levels were on the normal range. The incidence of osteopetrosis in our country Is very low and its association with short stature and delayed puberty is well known. The dysplasic bone associated to chronic anemia and repeated infections present mainly in the severe forms of the disease are probably the major causes for the delayed development.A osteopetrose é uma doença genética rara, com variação na sua expressividade e no seu modo de herança e que caracteriza-se, básicamente, pela esclerose óssea generalizada resultado de um desequilibrio entre formação e reabsorçâo ósseas. Descreveremos um caso desta doença em que um retardo de desenvolvimento associado a fraturas ósseas iniciaram a investigação. E.D.C., 19 anos e 9 meses, foi encaminhado ao serviço médico por alteração esquelética e baixa estatura. Iniciou aumento de volume testicular e pilificaçâo pubiana aos 18 anos, com progressão lenta da puberdade. Há 6 meses apresentou fratura de antebraço após queda da própria altura. Ao exame físico apresentava estatura de 141,5 cm; peso 38,5 kg; estadiamento puberal em GIII PII com idade óssea de 13 anos e 6 meses. O exame radiológico do esqueleto apresentou uma hiperdensidade óssea com alterações típicas de osteopetrose , com sinais de fratura em ulna e colo de fémur, ambos à direita. A densitometria óssea encontrava-se 10,65 e 15,55 desvios-padrão acima da média para sua idade em coluna lombar e fêmur respectivamente. As dosagens hormonais revelaram níveis reduzidos de testosterona total para a idade cronológica (245 ng/dl) com gonadotrofinas basais normais; hormônio de crescimento (GH) responsivo à hipoglicemia e níveis de fator de crescimento semelhante a insulina-l (IGF-I) diminuídos para o estádio puberal. Os níveis de cálcio (Ca), fósforo (P), atividade de fosfatase alcalina (FA) e paratormônio intacto (PTH) plasmáticos estavam dentro da normalidade. A incidência de osteopetrose em nosso meio é bastante rara, e sua associação com baixa estatura e retardo puberal é conhecida, sendo provavelmente de origem multifatorial, afetando mais intensamente as formas graves da doença, onde a anemia crônica e infecções de repetição estão presentes. As alterações displásicas do tecido ósseo e das cartilagens de crescimento inerentes a osteopetrose certamente desempenham um papel importante na baixa estatura.Universidade Federal de São Paulo (UNIFESP) Faculdade de Medicina de Pouso AlegreUNIFESP, Faculdade de Medicina de Pouso AlegreSciEL