Impaired muscle parameters in adults with mild to severe types of osteogenesis imperfecta: a cross-sectional study

Impaired muscle parameters may further compromise the already compromised skeleton in individuals with OI. This cross-sectional study aimed to compare muscle function and body composition in adults with various OI types and healthy controls. Sixty-eight adults with OI (mean age 42.2 yr; 27 men) and 68 healthy age- and sex-matched controls were recruited. Maximal isometric muscle force was assessed by handheld dynamometry (hand grip, hip flexors, shoulder abductors, and ankle dorsiflexors), muscle endurance by posture maintenance tests (shoulder abduction, hip flexion, and wall sit), and functional lower limb strength by 30-s chair rise test. In a sub cohort, dynamic muscle function (peak power and force) was assessed by a ground reaction force plate, and lean and fat mass, muscle and fat cross-sectional area (CSA), and muscle density by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Multiple linear regression models were fitted with group (OI type I, III, IV/V, or controls), country, sex, and age in the fixed effects part. Overall, adults with various types of OI had lower isometric, endurance, and functional muscle strength (mean difference [MD] = OI type I: 19-43%, OI type IV/V: 25-68%, OI type III: 20-72%) compared to controls. Furthermore, adults with OI type I had lower dynamic muscle function (peak force [MD = 25-29%] and power [MD = 18-60%]), lean mass (MD = 10-17%), muscle CSA (MD = 9-21%), and muscle density (MD = 2-3%) but higher adiposity indices (MD = 24-42%) compared to controls. Functional lower limb strength and maximal muscle force were significantly different between OI types, whereas muscle endurance was not. To conclude, adults with OI present with markedly impaired muscle function which may partially be explained by their altered body composition. Our findings emphasize the need for proper assessment of various muscle parameters and (research into) appropriate and safe muscle strengthening approaches in this population.

Correlation of lipocalin 2 and glycolipid metabolism and body composition in a large cohort of children with osteogenesis imperfecta

PURPOSE

Lipocalin 2 (LCN2) is a newly recognized bone-derived factor that is important in regulation of energy metabolism. We investigated the correlation of serum LCN2 levels and glycolipid metabolism, and body composition in a large cohort of patients with osteogenesis imperfecta (OI).

METHODS

A total of 204 children with OI and 66 age- and gender-matched healthy children were included. Circulating levels of LCN2 and osteocalcin were measured by enzyme-linked immunosorbent assay. Serum levels of fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), and low- and high-density lipoprotein cholesterol (LDL-C, HDL-C) were measured by automated chemical analyzers. The body composition was measured by dual-energy X-ray absorptiometry. Grip strength and timed-up-and-go (TUG) were tested to evaluate the muscle function.

RESULTS

Serum LCN2 levels were 37.65 ± 23.48 ng/ml in OI children, which was significantly lower than those in healthy control (69.18 ± 35.43 ng/ml, P < 0.001). Body mass index (BMI) and serum FBG level were significantly higher and HDL-C levels were lower in OI children than healthy control (all P < 0.01). Grip strength was significantly lower (P < 0.05), and the TUG was significantly longer in OI patients than healthy control (P < 0.05). Serum LCN2 level was negatively correlated to BMI, FBG, HOMA-IR, HOMA-β, total body, and trunk fat mass percentage, and positively correlated to total body and appendicular lean mass percentage (all P < 0.05).

CONCLUSIONS

Insulin resistance, hyperglycemia, obesity, and muscle dysfunction are common in OI patients. As a novel osteogenic cytokine, LCN2 deficiency may be relevant to disorders of glucose and lipid metabolism, and dysfunction of muscle in OI patients.

Familial gigantiform cementoma with recurrent ANO5 p.Cys356Tyr mutations: Clinicopathological and genetic study with literature review

BACKGROUND

Familial gigantiform cementoma (FGC) is a rare tumor characterized by the early onset of multi-quadrant fibro-osseous lesions in the jaws, causing severe maxillofacial deformities. Its clinicopathological features overlap with those of other benign fibro-osseous lesions. FGC eventually exhibits progressively rapid growth, but no suspected causative gene has been identified.

METHODS

In this study, three patients with FGC were recruited, and genomic DNA from the tumor tissue and peripheral blood was extracted for whole-exome sequencing.

RESULTS

Results showed that all three patients harbored the heterozygous mutation c.1067G > A (p.Cys356Tyr) in the ANO5 gene. Furthermore, autosomal dominant mutations in ANO5 at this locus have been identified in patients with gnathodiaphyseal dysplasia (GDD) and are considered a potential causative agent, suggesting a genetic association between FGC and GDD. In addition, multifocal fibrous bone lesions with similar clinical presentations were detected, including five cases of florid cemento-osseous dysplasia, five cases of polyostotic fibrous dysplasia, and eight cases of juvenile ossifying fibromas; however, none of them harbored mutations in the ANO5 gene.

CONCLUSION

Our findings indicate that FGC may be an atypical variant of GDD, providing evidence for the feasibility of ANO5 gene testing as an auxiliary diagnostic method for complex cases with multiple quadrants.

Photoanthropometric craniofacial parameters in individuals with osteogenesis imperfecta

BACKGROUND

This study aimed to evaluate facial photoanthropometric parameters in patients with OI.

MATERIAL AND METHODS

We selected 20 Brazilian patients diagnosed with OI treated at the Extension Service for Minors in Need of Specialized Treatment of the Dentistry Course at the Federal University of Ceará (Fortaleza, Brazil), of both sexes, without age restriction, and able to understand and sign the informed consent form (ICF). As a control group, 38 non-syndromic Brazilian individuals, categorized as ASA I, able to understand and sign the ICF, matched by sex, age, and Legan and Burstone facial profile were selected. The exclusion criteria were: previous orthodontic treatment, craniofacial trauma and/or surgery, and the presence of any other systemic diseases. Photoanthropometric analysis of the 18 facial parameters proposed by Stengel-Rutkowski et al. (1984), previously established in the literature for craniofacial syndromes, were conducted. A single examiner digitally performed all effective and angular measurements with the CorelDRAWX7® software.

RESULTS

Horizontally shortened ears (p<0.001) but larger in height in relation to the face (p=0.012) were shown to be alterations belonging to individuals with OI.

CONCLUSIONS

OI patients present distinct photoanthropometric parameters inherent in this condition.

Dominant negative variants in KIF5B cause osteogenesis imperfecta via down regulation of mTOR signaling

BACKGROUND

Kinesin motor proteins transport intracellular cargo, including mRNA, proteins, and organelles. Pathogenic variants in kinesin-related genes have been implicated in neurodevelopmental disorders and skeletal dysplasias. We identified de novo, heterozygous variants in KIF5B, encoding a kinesin-1 subunit, in four individuals with osteogenesis imperfecta. The variants cluster within the highly conserved kinesin motor domain and are predicted to interfere with nucleotide binding, although the mechanistic consequences on cell signaling and function are unknown.

METHODS

To understand the in vivo genetic mechanism of KIF5B variants, we modeled the p.Thr87Ile variant that was found in two patients in the C. elegans ortholog, unc-116, at the corresponding position (Thr90Ile) by CRISPR/Cas9 editing and performed functional analysis. Next, we studied the cellular and molecular consequences of the recurrent p.Thr87Ile variant by microscopy, RNA and protein analysis in NIH3T3 cells, primary human fibroblasts and bone biopsy.

RESULTS

C. elegans heterozygous for the unc-116 Thr90Ile variant displayed abnormal body length and motility phenotypes that were suppressed by additional copies of the wild type allele, consistent with a dominant negative mechanism. Time-lapse imaging of GFP-tagged mitochondria showed defective mitochondria transport in unc-116 Thr90Ile neurons providing strong evidence for disrupted kinesin motor function. Microscopy studies in human cells showed dilated endoplasmic reticulum, multiple intracellular vacuoles, and abnormal distribution of the Golgi complex, supporting an intracellular trafficking defect. RNA sequencing, proteomic analysis, and bone immunohistochemistry demonstrated down regulation of the mTOR signaling pathway that was partially rescued with leucine supplementation in patient cells.

CONCLUSION

We report dominant negative variants in the KIF5B kinesin motor domain in individuals with osteogenesis imperfecta. This study expands the spectrum of kinesin-related disorders and identifies dysregulated signaling targets for KIF5B in skeletal development.

One half-century of advances in the evaluation and management of disorders of bone and mineral metabolism in children and adolescents

The past 50 years of research in pediatric bone and mineral metabolism have led to remarkable progress in the identification and characterization of disorders that affect the developing skeleton. Progress has been facilitated through advances in both technology and biology and this paper provides a brief description of some but not all of the key findings, including identification of the calcium sensing receptor and the polypeptides parathyroid hormone and parathyroid hormone-related protein as well as their shared receptor and signal generating pathways; the elucidation of vitamin D metabolism and actions; discovery of fibroblast growth factor 23 (FGF23), the sodium-phosphate co-transporters and the other components that regulate phosphate metabolism. Moreover, the past half-century of research has led to the delineation of the molecular bases for genetic forms of hypoparathyroidism, pseudohypoparathyroidism, and primary hyperparathyroidism as well as the determination of the genetic causes of osteogenesis imperfecta, osteopetrosis, hypophosphatasia, and other disorders of mineral/bone homeostasis. During the next decade we expect that many of these fundamental discoveries will lead to the development of innovative treatments that will improve the lives of children with these disorders.

Transition of young adults with metabolic bone diseases to adult care

As more accurate diagnostic tools and targeted therapies become increasingly available for pediatric metabolic bone diseases, affected children have a better prognosis and significantly longer lifespan. With this potential for fulfilling lives as adults comes the need for dedicated transition and intentional care of these patients as adults. Much work has gone into improving the transitions of medically fragile children into adulthood, encompassing endocrinologic conditions like type 1 diabetes mellitus and congenital adrenal hyperplasia. However, there are gaps in the literature regarding similar guidance concerning metabolic bone conditions. This article intends to provide a brief review of research and guidelines for transitions of care more generally, followed by a more detailed treatment of bone disorders specifically. Considerations for such transitions include final adult height, fertility, fetal risk, heritability, and access to appropriately identified specialists. A nutrient-dense diet, optimal mobility, and adequate vitamin D stores are protective factors for these conditions. Primary bone disorders include hypophosphatasia, X-linked hypophosphatemic rickets, and osteogenesis imperfecta. Metabolic bone disease can also develop secondarily as a sequela of such diverse exposures as hypogonadism, a history of eating disorder, and cancer treatment. This article synthesizes research by experts of these specific disorders to describe what is known in this field of transition medicine for metabolic bone diseases as well as unanswered questions. The long-term objective is to develop and implement strategies for successful transitions for all patients affected by these various conditions.

Modified Velpeau Sling Application for the Treatment of Fractures Around Shoulder in Infants

BACKGROUND

Fractures around the shoulder region in infants are treated by arm-chest bandaging, adhesive strapping, or sling application. These conventional treatment methods are associated with issues like skin irritation, excoriation, movement of bone fragments causing muscle spasm, and difficulty in nursing care. We describe the technique of modified Velpeau sling application and reviewed its efficacy at a long-term follow-up.

METHODS

A retrospective study was conducted with 19 infants who presented between 2009 and 2018 to a tertiary care center in western India with either clavicle or humerus fracture. Inclusion criteria was any infant with humerus or clavicle fracture that underwent modified Velpeau sling application and had a minimum follow-up of 2 years. Patients were followed at weekly intervals until sling discontinuation based on the fracture healing. At further follow-up, children were assessed for the presence of angular or rotational malalignment and limb length discrepancy. Functional outcome was measured by the Paediatric Adolescent Shoulder Survey at the final follow-up.

RESULTS

Seven clavicle and 12 humerus fractures were treated with this technique. The mean age at presentation was 50 days (range, 1 d to 7 mo). The average follow-up was 6 years (range, 2 to 10 y). Two infants had underlying osteogenesis imperfecta. Infants without underlying pathology had no angular/rotational malalignment or limb length discrepancy, while both infants with underlying osteogenesis imperfecta had a varus alignment and shortening of the humerus. Infants without underlying pathology demonstrated good functional outcomes measured by the Paediatric Adolescent Shoulder Survey questionnaire, while those with pathology had functional limitations.

CONCLUSIONS

The modified Velpeau method is an effective way of treating fractures around the shoulder region in infants without underlying pathology. Several advantages such as accessibility of sling material, easy application, inexpensive material, and absence of skin-related complications make this an effective treatment.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Experiences of Women of Short Stature During the Perinatal Period

OBJECTIVE

To explore the experiences of women of short stature, including women with dwarfism and osteogenesis imperfecta (OI), during the perinatal period.

DESIGN

Qualitative descriptive.

SETTING

Telephone interviews with women of short stature from across the United States.

PARTICIPANTS

Nine women of short stature, including five with dwarfism and four with osteogenesis imperfecta, between the ages of 18 and 55 years who gave birth within the last 10 years.

METHODS

We used reflexive thematic analysis to analyze interview data.

RESULTS

Four themes represented the participants' experiences during maternity care: Clinicians' Lack of Knowledge, Sources of Information and EmotionalSupport, Clinical Considerations: Effects of Pregnancy and Disability, and Accessibility Barriers and Adaptations. Participants experienced respiratory difficulties and preterm birth. They expressed concerns regarding the lack of clinician knowledge and experience in administering epidural anesthesia to women of short stature and highlighted the important role of disability organizations in disseminating information about childbirth for women with disabilities.

CONCLUSION

Childbearing women of short stature require disability-specific maternity care. Our findings highlight the need for disability education programs for nurse-midwives, nurses, physicians, and other clinicians who provide maternity care to women of short stature.

Planned Preterm Delivery and Treatment of Severe Infantile FEVR With Osteoporosis-Pseudoglioma Syndrome

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary vitreoretinopathy resulting from mutations in the wnt signaling pathway leading to abnormalities in fetal retinal vasculogenesis, angiogenesis, and retinal vascular maintenance. Severe FEVR may result in congenital retinal detachment resembling Norrie disease. The authors report the first case of planned preterm delivery and treatment of a patient with severe FEVR from biallelic LRP5 mutations whose siblings had congenital tractional retinal detachments with light perception vision outcomes after conventional care. Early intervention allowed laser ablation of avascular retina and functional visual outcome despite a successfully repaired unilateral tractional retinal detachment. [Ophthalmic Surg Lasers Imaging Retina. 2022;53(4):228-232.].

Challenges with Fassier-Duval rod exchanges in congenital pseudarthrosis of the tibia: explant roadblock and solution

Congenital pseudarthrosis of the tibia (CPT) is characterized by anterolateral tibial bowing and hamartomatous periosteum that predisposes it to fracture. Fassier-Duval telescopic rods can improve the structural integrity of bone segments after reconstruction. We present our experience treating CPT with the Fassier-Duval rod and a novel technique for Fassier-Duval exchange that was developed after extraction failed in one patient. Patients were identified who underwent treatment with Fassier-Duval rods for CPT between 2007 and 2016 and had undergone their first rod exchange. Medical records were reviewed, and complications were classified using the system of Cherkashin. Four patients had an average age at the initial insertion of 6 years 4 months (4-9 years). The average follow-up duration after initial Fassier-Duval implantation was 5.4 years (2.7-8.1 years). Seven Category 2 complications were associated with the Fassier-Duval rod: interlocking K-wire migration (2), lengthening failure (2), explant failure (1), distal migration of female rod through physis (1) and male rod portion proximally migrating through physis (1). Three patients underwent one rod exchange [average 3.2 years after implantation (range, 2.7-3.9 years)]. One patient underwent two rod exchanges (2.9 and 6.9 years after initial implantation). The second attempt at exchange failed; this failure prompted the development of custom trephines to remove the hard bone that can encase the distal male segment. The use of custom trephines was made necessary by dense sclerotic bone at the previous pseudarthrosis site. We recommend that custom trephines be available during Fassier-Duval rod extraction to avoid failed retrieval. Level of evidence: Level IV (Case series).

The role of osteocalcin in regulation of glycolipid metabolism and muscle function in children with osteogenesis imperfecta

OBJECTIVE

Osteoblasts are discovered to secrete hormones with endocrine effects on metabolism, and osteocalcin (OC) is the most abundant non-collagenous protein in bone. We investigate the relationship between serum OC levels and glycolipid metabolism and muscle function in children with osteogenesis imperfecta (OI).

METHODS

A total of 225 children with OI and 80 healthy controls matched in age and gender were included in this single center study. Serum levels of fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C, HDL-C) were measured by automated analyzers. Serum levels of fasting insulin (FINS) were measured using an automated electrochemiluminescence system. Serum levels of OC and undercarboxylated osteocalcin (ucOC) were measured by enzyme-linked immunosorbent assay. Grip strength and timed-up-and-go (TUG) test were measured. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry.

RESULTS

OI patients had significantly higher body mass index (BMI), FBG, and HOMA-IR, but lower HDL-C levels, lower grip strength and longer TUG than control group (all P<0.05). Serum OC, ucOC levels, and ucOC/OC in OI type III patients were significantly lower than those in OI patients with type I and IV. Serum levels of OC, ucOC, and ucOC/OC were negatively correlated to BMI, FBG, insulin levels, and HOMA-IR (all P<0.05). The ratio of ucOC/OC was positively correlated to grip strength (r=0.512, P=0.036), lean mass percentage (%LM) of the total body and limbs, and negatively correlated to fat mass percentage (%FM) of the total body, %FM and fat mass index (FMI) of the trunk (all P<0.05).

CONCLUSIONS

Obesity, glucolipid metabolic abnormalities, and reduced grip strength were common in children with OI. Circulating osteocalcin and ucOC may play an important role in the regulation of glucose metabolism, as well as the muscle function of children with OI.

Decrease of lysyl hydroxylase 2 activity causes abnormal collagen molecular phenotypes, defective mineralization and compromised mechanical properties of bone

Lysyl hydroxylase 2 (LH2) is an enzyme that catalyzes the hydroxylation of lysine (Lys) residues in fibrillar collagen telopeptides, a critical post-translational modification for the stability of intermolecular cross-links. Though abnormal LH2 activities have been implicated in various diseases including Bruck syndrome, the molecular basis of the pathologies is still not well understood. Since LH2 null mice die at early embryonic stage, we generated LH2 heterozygous (LH2^+/-) mice in which LH2 level is significantly diminished, and characterized collagen and bone phenotypes using femurs. Compared to the wild-type (WT), LH2^+/- collagen showed a significant decrease in the ratio of hydroxylysine (Hyl)- to the Lys-aldehyde-derived collagen cross-links without affecting the total number of aldehydes involved in cross-links. Mass spectrometric analysis revealed that, in LH2^+/- type I collagen, the extent of hydroxylation of all telopeptidyl Lys residues was significantly decreased. In the helical domain, Lys hydroxylation at the cross-linking sites was either unaffected or slightly lower, but other sites were significantly diminished compared to WT. In LH2^+/- femurs, mineral densities of cortical and cancellous bones were significantly decreased and the mechanical properties of cortical bones evaluated by nanoindentation analysis were compromised. When cultured, LH2^+/- osteoblasts poorly produced mineralized nodules compared to WT osteoblasts. These data provide insight into the functionality of LH2 in collagen molecular phenotype and its critical role in bone matrix mineralization and mechanical properties.

[Analysis of COL1A1 gene variation and clinical prevention and treatment in patients with Van der Hoeve syndrome]

Objective: To investigate the clinical phenotype, treatment and prevention of Van der Hoeve syndrome, and analyze the variation characteristics of its related gene COL1A1. Methods: Hearing and sequencing data of syndromic deafness patients who had undergone genetic testing for deafness at the Chinese People's Liberation Army General Hospital since January 2008 to October 2020 were retrospectively reviewed. The variation of the COL1A1 gene and return visits to traceable patients and families were summarized, the disease progress and clinical treatment effects were analyzed, and the prevention strategies were discussed. Results: A total of 7 patients with COL1A1 gene mutation underwent clinical intervention. The mutation sites were c.1342A>T (p.Lys448*), c.124C>T (p.Gln42*), c.249insG(p.Ala84*), c.668insC(p.Gly224*), c.2829+1G>C, c.1081C>T (p.Arg361*), c.1792C>T (p.Arg598*), of which c.1081C>T and c.1792C>T had been previously reported, and the remaining 5 were novo mutations that have not been reported. All the 7 probands underwent stapes implantation and received genetic counseling and prevention guidance. Conclusions: Van der Hoeve syndrome belongs to osteogenesis imperfecta type Ⅰ. The disease has high penetrance. Timely surgical intervention for hearing loss can improve the life quality in patients. Accurate genetic counseling and preimplantation genetic diagnosis can achieve the primary prevention for the disease.

Eat, breathe, sleep with Osteogenesis Imperfecta

BACKGROUND

Although Osteogenesis Imperfecta (OI) affects the connective tissue causing extremely brittle bones with consequent skeletal deformities, it is important to go beyond bones. Indeed, the quality of life in OI does not only depend on bones status, as OI might affect also other important functions. We have therefore implemented a multidisciplinary study to assess lung function, breathing pattern, sleep quality and nutritional status in 27 adult OI type III and IV patients (median age: 34.6 years; 19 women; 14 type III).

RESULTS

According to nocturnal oxygen desaturation, two groups were identified: 13 patients with (OI_OSA, incidence: 48.2%) and 14 without (no_OSA) obstructive sleep apnea. The former was characterized by higher spinal and ribcage deformity, by more restrictive lung function, by paradoxical thoracic breathing in supine position, by rapid and shallow breathing, by higher body mass index, by longer neck and waist circumferences; by higher abdominal volume and by greater percentage of body fat mass, particularly localized in the trunk. The best predictor of OI_OSA was the negative value of the supine ribcage contribution to tidal volume, followed by the ratio between the neck and the waist circumferences with body height and the supine thoraco-abdominal volumes phase shift angle.

CONCLUSIONS

The pathophysiology of OI ensued a dangerous vicious circle, in which breathing, sleep and nutritional status are tightly linked, and they might all end up in negatively affecting the quality of life. The vicious circle is fed by some intrinsic characteristics of the disease (thoracic, cranial and mandibular deformities) and some bad daily habits of the patients (i.e. physical inactivity and low dietary quality). The former impacts on restricting the respiratory function, the latter makes Olers more prone to experience overweight or obesity. The main consequence is a high incidence of obstructive sleep apnea, which remains an underdiagnosed disorder in individuals with severe OI who are obese, with a neck to height ratio over than 31.6%, and characterized by paradoxical breathing in supine position. A multidisciplinary approach, including evaluations of breathing, sleep and nutrition, is required to better manage the disease and fulfil the maximizing well-being of OI patients.

Interlocking Fixation in Fassier-Duval Rods: Performance and Success Factors

INTRODUCTION

Pediatric patients with osteogenesis imperfecta (OI) can be treated with intramedullary Fassier-Duval rod (FDR) systems for limb deformity or recurrent fractures. Single-interlocking pins can improve epiphyseal fixation, but there is a paucity of literature examining incidence of rod migration or pin backout long-term. The purpose of this study is to quantify rates of rod migration and pin backout in OI patients treated with single-interlocking FDRs.

METHODS

A retrospective chart review was performed on pediatric patients treated at a tertiary care center across a 15-year period. Inclusion criteria to select patients was: (1) Pediatric patients (below 18 y of age); (2) Patients with confirmed OI; and (3) Patients with lower extremity fractures or deformity treated with FDRs with distal interlocking pins. Age at time of surgery, rates of obturator migration and pin backout and prominence were collected. We recorded if pin tips were bent by the surgeon during the procedure. Bivariate statistics were used to analyze risk factors for pin backout and prominence.

RESULTS

Twenty-four single-interlocking pin FDRs (21 tibia, 3 femur) were identified. The mean age at index surgery was 5.7±3.4 years, with the mean follow-up time of 7.2±4.7 years. Fourteen (58%) rods underwent revision surgery. Obturator proximal migration was observed in 3/24 rods (13%). No cases of obturator distal migration were observed (0/24, 0%). Mean proximal obturator migration was 2.16±1.8 cm. Revision for pin backout was observed in 10 (42%) rods and pin prominence in 11 (46%) extremities. Bending interlocking pins on at least 1 end was associated with decreased pin backout (P=0.01) and prominence (P=0.04).

CONCLUSIONS

Even with distal interlocking pins, the obturator of FDRs can still migrate over time. Pin backout is a common indication for revision surgery. Bending interlocking pins can decrease rates of pin backout and prominence.

LEVEL OF EVIDENCE

Level III.

Lethal and life-limiting skeletal dysplasias: Selected prenatal issues

Skeletal dysplasias are a heterogeneous group of congenital bone and cartilage disorders with a genetic etiology. The current classification of skeletal dysplasias distinguishes 461 diseases in 42 groups. The incidence of all skeletal dysplasias is more than 1 in every 5000 newborns. The type of dysplasia and associated abnormalities affect the lethality, survival and long-term prognosis of skeletal dysplasias. It is crucial to distinguish skeletal dysplasias and correctly diagnose the disease to establish the prognosis and achieve better management. It is possible to use prenatal ultrasonography to observe predictors of lethality, such as a bell-shaped thorax, short ribs, severe femoral shortening, and decreased lung volume. Individual lethal or life-limiting dysplasias may have more or less specific features on prenatal ultrasound. The prenatal features of the most common skeletal dysplasias, such as thanatophoric dysplasia, osteogenesis imperfecta type II, achondrogenesis, and campomelic dysplasia, are discussed in this article. Less frequent dysplasias, such as asphyxiating thoracic dystrophy, fibrochondrogenesis, atelosteogenesis, and homozygous achondroplasia, are also discussed.

Surgical Treatment of Pathological Tibial Shaft Fracture in Adult Patient With Gnathodiaphyseal Dysplasia: A Case Report

CASE

Gnathodiaphyseal dysplasia is a generalized skeletal syndrome characterized by frequent bone fractures in childhood, sclerosis and bowing of tubular bones, and cemento-osseous lesions of the jawbones. We present the case of a 53-year-old man with gnathodiaphyseal dysplasia who presented with pathological fracture of the tibial shaft. Internal fixation with the Ender nail was successfully performed with 2 years of follow-up.

CONCLUSION

This is the first report describing the treatment of fracture in an adult patient with gnathodiaphyseal dysplasia. Internal fixation with the Ender nail was effective for the tubular bone with deformity. Callus formation was observed without delay.

Trophic effects of multiple administration of mesenchymal stem cells in children with osteogenesis imperfecta

The safety of mesenchymal stem cell therapy for osteogenesis imperfecta has been demonstrated previously. However, it is unknown how the trophic effects are mediated by stem cells. In the present commentary, we bring to the attention of readers the recent report by Infante et al in the journal of clinical and translational medicine. The TERCELOI clinical trial presented the possible paracrine effect of transplanted MSCs in vitro and in vivo using proteomics and transcriptomic analysis. This novel finding adds new knowledge in the field of regenerative medicine. However, the scarcity of solid evidence in growth warrants a more thorough discussion.

Feasibility of Dual Energy X-Ray Absorptiometry Based Images for Measurement of Height, Sitting Height, and Leg Length in Children

BACKGROUND

Interpretation of pediatric bone mineral density by dual energy absorptiometry (DXA) requires adjustment for height (Ht). This is often not easily obtainable in nonambulant subjects.

AIMS

To investigate the feasibility of using DXA images to evaluate measurements of Ht, sitting height (SH), and leg length (LL).

METHODOLOGY

A total of 2 observers performed measurements of Ht, SH, and LL on 3 separate occasion using DXA digital images in 125 children. Intraclass correlation and relative technical error of measurement (rTEM) were performed to assess reliability of repeated measurements. In 25 children, Ht and SH were measured in clinic on the same day and Bland-Altman analysis was performed to compare DXA measured Ht, SH, LL with clinic measurements for these 25 children.

RESULTS

Intraclass correlation for DXA based Ht, SH, and LL measurements ranged from 0.996 to 0.998 (p < 0.0001). rTEM of Ht, SH, and LL for observer 1 was 0.0016%, 0.002%, and 0.0034%, respectively. rTEM of Ht, SH, and LL between observer 1 and 2 was 0.0047%, 0.0049%, and 0.0087%, respectively. Mean difference between clinic and DXA measurements from Bland-Altman plots were +0.57 cm (95% confidence interval [CI] -0.54 to +1.68) for Ht, +1.33cm (-1.60 to +4.24) for SH, and -0.76cm (-3.88 to +2.37) for LL.

CONCLUSIONS

Our study demonstrated for the first time that Ht, SH, and LL in children can be measured very precisely using DXA images. Ht can be measured accurately. We believe this may be a convenient method to obtain Ht measurements to allow size adjustment of DXA bone mineral density in immobile children with chronic conditions.

Muscle contraction induces osteogenic levels of cortical bone strain despite muscle weakness in a mouse model of Osteogenesis Imperfecta

Mechanical interactions between muscle and bone have long been recognized as integral to bone integrity. However, few studies have directly measured these interactions within the context of musculoskeletal disease. In this study, the osteogenesis imperfecta murine model (oim/oim) was utilized because it has both reduced bone and muscle properties, allowing direct assessment of whether weakened muscle is able to engender strain on weakened bone. To do so, a strain gauge was attached to the tibia of healthy and oim/oim mice, muscles within the posterior quadrant of the lower hind limb were stimulated, and bone strain during muscle contraction was measured. Results indicated that the relationship between maximum muscle torque and maximum engendered strain is altered in oim/oim bone, with less torque required to engender strain compare to wild-type and heterozygous mice. Maximum muscle torque at 150 Hz stimulation frequency was able to engender ~1500 μɛ in oim/oim animals. However, even though the strain engendered in the oim/oim mice was high relative to historical bone formation thresholds, the maximum strain values were still significantly lower than that of the wild-type mice. These results are promising in that they suggest that muscle stimulation may be a viable means of inducing bone formation in oim/oim and potentially other disease models where muscle weakness/atrophy exist.

[Homeostasis and Disorder of Musculoskeletal System.Diagnosis and Treatment of Congenital Musculoskeletal Diseases.]

Congenital skeletal dysplasias have been considered to be fundamentally untreatable diseases. However, molecular diagnosis by genetic testing has become more prevalent, and efforts are being made to develop novel therapies based on the pathogenesis. As treatments for osteogenesis imperfecta, in addition to anti-resorptive agents, neutralizing antibodies against sclerostin and transforming growth factor(TGF)-β and chemical chaperones can be beneficial. Enzyme replacement therapy using bone-targeting recombinant alkaline phosphatase has been recently developed to treat hypophosphatasia and has much improved the prognosis of the patients affected with severe forms of the disease. To treat the severe short stature in achondroplasia, drugs targeting the fibroblast growth factor receptor 3(FGFR3)-mediated signal are in development for clinical use.

[Secondary osteoporosis. Disease-Related Osteoporosis in Children.]

Similarly to adult osteoporosis, childhood osteoporosis also is usually divided into primary and secondary causes. Primary osteoporosis includes genetic disorders represented by osteogenesis imperfecta. Secondary pediatric osteoporosis is associated with various diseases and glucocorticoid treatment, and malnutrition, impaired mobility, chronic inflammation and endocrine disorders can be risk factors. In growing children, mild osteoporosis can be spontaneously recovered by elimination of risk factors. However, initiation of treatment using drugs such as bisphosphonate should be considered in primary osteoporosis including osteogenesis imperfecta and severe secondary osteoporosis which cannot be spontaneously improved. Administration of bisphosphonate increased bone mineral density in pediatric patients, but long-term safety and efficacy need further investigation. Development of new drugs to treat osteogenesis imperfecta is underway, which include the antibodies against sclerostin and TGF-β.

Sleep-Disordered Breathing in Children with Rare Skeletal Disorders: A Survey of Clinical Records

OBJECTIVE

Craniofacial disharmony in skeletal diseases is strongly associated with sleep-disordered breathing. This study was aimed at studying the sleep respiratory patterns in young children with rare skeletal disorders.

DESIGN

This retrospective study included children with achondroplasia (ACH), osteogenesis imperfecta (OI) and Ellis van Creveld Syndrome. Our subjects underwent an in-laboratory overnight respiratory polygraph between January 2012 and April 2016. All medical records were reviewed and brain Magnetic Resonance Imaging was conducted on patients with ACH, nasopharynx, oropharynx and laryngopharynx spaces.

PATIENTS

Twenty-four children were enrolled, 13 with ACH, 2 with spondyloepiphyseal dysplasia, 1 with odontochondrodysplasia, 6 with OI and 2 with Ellis van Creveld Syndrome.

RESULTS

Children with ACH, who had adenotonsillectomy, showed fewer sleep respiratory involvement than untreated children. Among 13 patients with ACH, brain magnetic resonance imaging was available in 10 subjects and significant negative correlation was found between sleep respiratory patterns, nasopharynx and oropharynx space (p < 0.05). In 2 patients with spondyloepiphyseal dysplasia, mild-to-moderate sleep respiratory involvement was found. Both subjects had a history of adenotonsillectomy. Mild sleep respiratory involvement was also observed in 4 out of 6 patients with OI. One patient with Ellis van Creveld syndrome had mild sleep respiratory disturbance.

CONCLUSIONS

Sleep respiratory disturbances were detected in children with ACH, and with less severity also in OI and Ellis van Creveld syndrome. Adenotonsillectomy was successful in ACH in reducing symptoms. In light of our findings, multicenter studies are needed to obtain further information on these rare skeletal diseases.

[Spectrum of COL1A1/2 mutations and gene diagnosis in Chinese patients with osteogenesis imperfecta]

OBJECTIVE

To identify mutations of the type I collagen genes (COL1A1 and COL1A2) in the affected with osteogenesis imperfecta (OI), to establish the spectrum of COL1A1/2 mutations in Chinese OI patients, and to provide prenatal gene diagnosis to the fetuses at high risk.

METHODS

Genomic DNA was extracted from peripheral blood by the standard SDS-proteinase K-phenol/chloroform method. All the coding regions and exon/intron boundaries of COL1A1/2 were screened in 200 OI cases by conventional Sanger sequencing and targeted next-generation sequencing (NGS) on Ion Torrent-personalized genome sequencing operation (Ion PGM™). For familial cases, candidate mutations were validated in all available family members using high resolution melting analysis (HRM). In sporadic cases, only parents were examined to determine the origin of the identified mutation.Prenatal gene diagnosis was carried out by PCR direct sequencing and linkage analysis using microsatellite markers.

RESULTS

In total, the authors identified 125 differently pathogenic mutations, including 74 in COL1A1 and 51 in COL1A2, in 158 probands, with a mutation detection rate of 79% (158/200). Among the 125 identified mutations, there were 63 novel mutations (33 in COL1A1 and 30 in COL1A2) and 13 recurrent mutations found in 46 probands (seven mutations recurring for two times, and the other six mutations recurring for more than 4 times). They performed prenatal genetic testing in 74 fetuses and found that 40 ones carried COL1A1/2 mutations identified in the corresponding probands.

CONCLUSIONS

The authors have developed a combined approach for genetic testing of OI, extended the COL1A1/2 mutation spectrum in Chinese OI patients, and confirmed gene diagnosis in a relatively large cohort of OI probands and fetuses.

A Case Report for a Complex Denture Case on a Special Care Patient with Osteogenesis Imperfecta

This case report presents a patient with Dentogenesis Imperfecta (DI) associated with Osteogenesis Imperfecta (OI) and its subsequent dental manifestations. The patient in this report (see Figure 1) has spent his life living with his disability type III OI (also known as brittle bone disease) and its degenerative affects. The patient is independent and enjoys his social life but felt his existing dentures were having an adverse effect on the quality of his life. The patient attended Dorset County Hospitals Special Care Dentistry and on clinical examination it was noted the patient was partially dentate with a class III malocclusion and brownish discoloration of the remaining teeth caused by enamel hypoplasia. Treatment for this patient would entail making a maxillary complete denture and a mandibular partial chrome denture, normally quite simple tasks but due to the DI and its dental manifestations, the treatment would be complicated. This case demonstrates how a complex case treated by a collaborative dental team using their different skills and knowledge can lead to a successful and rewarding treatment for both patient and team.

Case Histories

Conditions related to abnormalities of calcium and bone metabolism are large in number and are characterised by hypocalcaemia, hypercalcaemia, primary and secondary osteoporosis, rickets resulting from both vitamin D and phosphate metabolism disorders, and a series of miscellaneous conditions. Included in this chapter is a series of cases drawn from our clinics and from colleagues who have presented these clinical problems at the recent Advanced Courses in Paediatric Bone and Calcium Metabolism run by the British Paediatric and Adolescent Bone group. This series of cases is not fully comprehensive but is designed to cover the major aspects of bone- and calcium-related disorders.

Validity of an accelerometer as a vertical ground reaction force measuring device in healthy children and adolescents and in children and adolescents with osteogenesis imperfecta type I

INTRODUCTION

Vertical ground reaction forces (vGRFs) are closely related to bone strength and development. It is therefore relevant to assess these forces in bone disorders accompanied with muscle weakness such as in osteogenesis imperfecta type I (OI type I). The purpose of the present study was to assess the validity of vGRFs derived from an accelerometer.

METHODS

Fourteen children and adolescents with a diagnosis of OI type I (age range: 7 to 21; mean age [SD]: 14.1 [4.8] years; 5 males) and fourteen healthy controls (age range: 6 to 21; mean age [SD]: 12.5 [4.2] years; 5 males) performed three repetitions of five different jump and rise tests on a ground reaction force plate. Jumps and rises outcomes were measured simultaneously with the ground reaction force plate and an accelerometer.

RESULTS

Pearson correlation coefficients were over 0.96 (p<0.001) for the five tests. The limits of agreement represented between 17 and 31% of the average peak force measured by both devices. The accelerometer is a promising tool to assess ground reaction forces in everyday life settings and has been shown to be sufficiently sensitive to detect muscular weakness in children and adolescent with OI type I.

Osteogenesis imperfecta: effecting the transition from adolescent to adult medical care

The objective of this paper is to provide guidelines for pediatricians, adult physicians in different medical disciplines and patients' families who are planning the transition to adult care for the adolescent with osteogenesis imperfecta (OI). This observational report reflects concerns expressed by patients, their families, and involved physicians regarding the problems encountered with the transition of care. Methods for dealing with transitional issues are presented. OI is a heritable disorder of connective tissue in which fractures are the dominant clinical feature. However, OI is a systemic disorder with broad clinical variability in which there are unpredictable episodes of trauma. Coordinated team support provides the best level of care for the child with OI. This paper discusses 4 key topics related to effecting the transition from pediatric to adult care: 1) Transitioning and maintaining health, 2) Preserving or improving the level of function, 3) Assuring continuity of medical/surgical care, and 4) Re-structuring psychosocial and work-related systems. The process of transition requires active communication between the pediatric and adult team members along with a proactive approach by the patient and family. In addition, as the transition is established, the patient with OI should be encouraged to be his/her own advocate and care coordinator.

[Anesthetic treatment of patients with osteogenesis imperfecta]

BACKGROUND AND OBJECTIVE

Although the prevalence of osteogenesis imperfecta is low, the effect of this hereditary disease on patients' quality of life is considerable. We report our experience in the perioperative management of patients with this condition in our hospital.

PATIENTS AND METHODS

Retrospective study describing the interventions on patients with this disease in our hospital from 1991 to 2009. We analyzed demographic data, disease variants, concomitant disorders, surgical procedures, type of anesthesia, and intraoperative and postoperative complications.

RESULTS

From 1991 to 2009, 105 procedures were performed on 29 patients (ages 1 to 25 years) with osteogenesis imperfecta (37.9% women and 62.1% men). The most common type of osteogenesis imperfecta was type III (65.5%). Most patients (93%) had no associated diseases. Two patients were allergic to latex. No complications occurred in 62% of interventions. Reported complications during surgery were 1 case of non-malignant hyperthermia and 1 contralateral femur fracture.

CONCLUSIONS

The prevalence of osteogenesis imperfecta is low. Treatment requires a multidisciplinary approach, in which appropriate perioperative management must be based on a proper understanding of the skeletal and extraskeletal abnormalities associated with this disease.

[Genetic basis for skeletal disease. Dental management of patients with bone diseases]

Malformation of teeth can be found in patients with bone diseases, which was induced when the disease occurred during the tooth formation. The tooth malformation shows typical manifestations of the disease, which may demonstrate the occurrence of the bone disease. In this article, dental management of the patients with bone diseases such as X-linked hypophosphatemic rickets, osteogenesis imperfecta, and hypophosphatasia was presented.

A case of brittle bone disease

Brittle bone disease--synonym, osteogenesis imperfecta is a rare genetic disorder of collagen synthesis associated with broad spectrum of musculoskeletal problem, where bones break easily. Recently we got a case of OI, whose name is Babu, 3 days old, full term bay with uneventful home delivery. The baby had multiple fractures in all the extremities with deformities with blue sclera with bilateral inguinal hernia. Other systems were found normal. On 10th day of life he was operated for inguinal hernia with satisfactory postoperative recovery and subsequently he was referred to the orthopedic department for further management.

In vivo expression of human growth hormone by genetically modified murine bone marrow stromal cells and its effect on the cells in vitro

Human growth hormone (hGH) is frequently used clinically for growth abnormalities in children and also in adults with growth hormone deficiency. The hormone is usually administered to the individuals by frequent injections. In the present study we investigated the potential of bone marrow stromal cells as vehicles to deliver the GH in vivo by infusion of cells transduced with hGH cDNA into mice femurs. The effect of the hormone on the transduced cells in vitro was also assessed. Bone marrow stromal cells established from a mouse model of human osteogenesis imperfecta mice (oim) were transduced with a retrovirus containing hGH and neomycin resistance genes. The hGH-expressing cells were selected in a medium containing G418 and were then assessed for the hGH expression in vitro. The selected cells synthesized 15 ng/10(6) cells of hGH per 24 h in vitro and exhibited alkaline phosphatase activity when they were treated with the human recombinant bone morphogenetic protein 2 (rhBMP-2). The transduced cells also proliferated faster than the LacZ transduced cells but they did not exhibit a higher rate of matrix synthesis. When 2 x 10(6) hGH+ cells were injected into the femurs of mice, hGH was detected in the serum of the recipient mice up to 10 days after injection. The highest level of growth hormone expression, 750 pg/ml, was detected in the serum of the recipient mice I day after injection of the transduced cells. hGH was also detected in the medium conditioned by cells that were flushed from the femurs of the recipient mice at 1, 3, and 6 days after cell injection. These data indicate that bone marrow stromal cells could potentially be used therapeutically for the delivery of GH or any other therapeutic proteins targeted for bone. The data also suggest that GH may exert its effects on bone marrow stromal cells by increasing their rate of proliferation.