Characterising and treating osteogenesis imperfecta

The experiences of the families with children diagnosed with osteogenesis imperfecta: A Qualiative study in Turkey

BACKGROUND

The diagnosis of osteogenesis imperfecta affects the whole lives of family members. This study aims to investigate the lived experience of families with children diagnosed with osteogenesis imperfecta.

DESIGN AND METHODS

This study used a qualitative, phenomenological design. The study sample consisted of parents of the children who were followed up with the diagnosis of osteogenesis imperfecta in the pediatric endocrinology clinic in Turkey. In order to collect data, a semi-structured interview form was prepared, and data were collected by way of face-to-face interviews. The lived experience of families were analyzed using qualitative methods. The life experiences of the families were analyzed in depth using qualitative methods.

RESULTS

In the study, six themes were identified, including having a child diagnosed with osteogenesis imperfecta, family process, life patterns, emotional dimension, social life, and economic dimension. The results revealed that parents did not know about the disease upon learning of the child's diagnosis. Parents stated that they experienced anxiety, disappointment, sadness, denial, and despair when they first learned about their children's diagnosis. They also indicated that having a child with osteogenesis imperfecta affected the whole family in physiological, psychological, and social aspects.

CONCLUSION

Parents and children should be given information about the disease since the first diagnosis of osteogenesis imperfecta, and psychosocial support should be provided. Families that can not get sufficient psychosocial support experience difficulties in the medical and care management of the disease.

PRACTICE IMPLICATIONS

Knowing and understanding the lived experiences of families living with osteogenesis imperfecta can guide the planning and implementation of quality nursing care processes.

Outcomes of Pediatric Osteogenesis Imperfecta Patients Requiring Port-a-Cath Placement for Long-Term Vascular Access

Intravenous (iv) bisphosphonates are widely used to treat the skeletal manifestations of osteogenesis imperfecta (OI). Obtaining peripheral iv access in pediatric patients with OI is often difficult and traumatic. Although this may be mitigated with surgically placed iv ports (port-a-caths), surgeons may be hesitant to perform this procedure on these children because of the lack of safety data. This study aims to gain better insight into the safety and efficacy of port-a-cath use in this population and identify risk factors for port-a-cath complications. In the present study, we conducted a retrospective cohort analysis of patient characteristics and the incidence of port-a-cath-related complications in children with OI. Fifty-three port-a-caths were placed in 29 children (21 males and 8 females). Of the 29 patients, most are OI type III (n = 18), followed by type I (n = 4), type IV (n = 4), and type V (n = 3). At the time of initial port-a-cath placement, the median age was 52 months (10-191 months), and the median weight was 7.9 kg (5.1-41.1 kg). Most patients (n = 20) weighed less than 10 kg during initial placement. Weight correlated significantly with OI type (p = 0.048), sex (p = 0.03), and vessel used (p = 0.02). Median initial port-a-cath longevity was 43 months (1-113 months), and we found no significant difference in port-a-cath longevity between sexes, OI types, or vessels used. Most patients (n = 19) required multiple port-a-cath placements. There is a significant difference (p = 0.02) between the number of placements and OI type, with type IV having more than type III. Port-a-cath removal was almost always due to mechanical complications (n = 19) but also for infection (n = 1) and malposition (n = 1). Eight patients still had their initial port-a-caths in place at the conclusion of this study. These findings indicate that complications associated with port-a-cath placement are mild and can be used to safely deliver iv bisphosphonates to pediatric OI patients. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Targeting transforming growth factor- β (TGF-β) for treatment of osteogenesis imperfecta

BACKGROUND

Currently, there is no disease-specific therapy for osteogenesis imperfecta (OI). Preclinical studies have shown that excessive TGF-β signaling is a driver of pathogenesis in OI. Here, we evaluated TGF-β signaling in children with OI and translated this discovery by conducting a phase 1 clinical trial of TGF-β inhibition in adults with OI.

METHODS

Histology and RNASeq were performed on bones obtained from children affected (n=10) and unaffected (n=4) by OI. Gene Ontology (GO) enrichment assay, gene set enrichment analysis (GSEA), and Ingenuity Pathway Analysis (IPA) were used to identify key dysregulated pathways. Reverse-phase protein array (RPPA), Western blot (WB), and Immunohistochemistry (IHC) were performed to evaluate changes at the protein level. A phase 1 study with a single administration of fresolimumab, a pan-anti-TGF-β neutralizing antibody, was conducted in 8 adults with OI. Safety and effects of fresolimumab on bone remodeling markers and lumbar spine areal bone mineral density (LS aBMD) were assessed.

RESULTS

OI bone demonstrated woven structure, increased osteocyte density, high turnover, and reduced bone maturation. SMAD phosphorylation was the most significantly up-regulated GO molecular event. GSEA identified TGF-β pathway as top activated signaling pathway in OI. IPA showed that TGF-β was the most significant activated upstream regulator mediating the global changes identified in OI bone. Treatment with fresolimumab was well-tolerated and associated with increase in LS aBMD in participants with OI type IV, while those with more severe OI type III and VIII had unchanged or decreased LS aBMD.

CONCLUSIONS

Our data confirm that TGF-β signaling is a driver pathogenic mechanism in OI bone and that anti-TGF-β therapy could be a potential disease-specific therapy with dose-dependent effects on bone mass and turnover.

TRIAL REGISTRATION

NCT03064074 FUNDING. This work was supported by the Brittle Bone Disorders Consortium (BBDC) (U54AR068069). The BBDC is a part of the National Center for Advancing Translational Science's (NCATS') RDCRN. The BBDC is funded through a collaboration between the Office of Rare Disease Research (ORDR) of NCATS, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institute of Dental and Craniofacial Research (NIDCR), National Institute of Mental Health (NIMH) and National Institute of Child Health and Human Development (NICHD). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. The BBDC was also supported by the OI Foundation. The work was supported by The Clinical Translational Core of BCM IDDRC (P50HD103555) from the Eunice Kennedy Shriver NICHD. Funding from the USDA/ARS under Cooperative Agreement No. 58-6250-6-001 also facilitated analysis for the study procedures. The contents of this publication do not necessarily reflect the views or policies of the USDA, nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government. The study was supported by a research agreement with Sanofi Genzyme.

Long-term vascular access for infants with moderate to severe osteogenesis imperfecta

PURPOSE

Osteogenesis imperfecta (OI) is a genetic disorder that causes skeletal fragility. For the most fragile infants and young children with OI, intravenous (IV) bisphosphonate administration is essential, but IV access attempts often cause fractures. Port-a-caths help prevent these events, but some surgeons are hesitant to insert these devices in these infants due to lack of data on their safety.

METHODS

Retrospective study of pediatric patients with OI who underwent port-a-cath placement from 1999 to 2018; incidence of complications such as infection and thrombosis and need for reoperation or replacement are described.

RESULTS

Port-a-caths were placed in 17 patients with OI (median age, 8 mos [5-23 mos]; median weight, 5.8 kg [3.96-9.08 kg]) and remained in place for a median of 53.5 mos (10-127 mos). One port-a-cath was replaced because of thrombosis. Two port-a-caths were removed because of malfunction, one for skin erosion, and one for infection. In these five cases, replacement was not needed because patients could safely tolerate IV access. Two patients have their port-a-cath in place and the remaining ten patients had theirs removed electively as it was no longer needed.

CONCLUSION

Port-a-cath placement in pediatric patients with OI is safe and efficacious for durable central access, enabling reliable IV bisphosphonate delivery and reducing iatrogenic trauma.

Diagnostic performance of morphometric vertebral fracture analysis (MXA) in children using a 33-point software program

BACKGROUND

There is significant inter and intraobserver variability in diagnosing vertebral fractures in children.

PURPOSE

We aimed to evaluate the diagnostic accuracy of morphometric vertebral fracture analysis (MXA) using a 33-point software program designed for adults, on dual-energy x-ray absorptiometry (DXA) images of children.

MATERIALS AND METHODS

Lateral spine DXA images of 420 children aged between 5 and 18 years were retrospectively reviewed. Vertebral fracture assessment (VFA) by an expert pediatric radiologist using Genant's semiquantitative scoring system served as the gold standard. All 420 DXA scans were analyzed by a trained radiographer, using semi-automated software (33-point morphometry). VFA of a random sample of 100 DXA was performed by an experienced pediatric clinical scientist. MXA of a random sample of 30 DXA images were analyzed by three pediatric radiologists and the pediatric clinical scientist. Diagnostic accuracy and inter and intraobserver agreement (kappa statistics) were calculated.

RESULTS

Overall sensitivity, specificity, false positive (FP) and false negative (FN) rates for the radiographer using the MXA software were 80%, 90%, 10%, and 20% respectively and for mild fractures alone were 46%, 92%, 8%, and 54% respectively. Overall sensitivity, specificity, FP, and FN rates for the four additional observers using MXA were 89%, 79%, 21%, and 11% respectively and for mild fractures alone were 36%, 86%, 14%, and 64% respectively. Agreement between two expert observers was fair to good for VFA and MXA [kappa = 0·29 to 0·76 (95% CI: 0·17-0·88) and 0·29 to 0·69 (95% CI: 0·17-0·83)] respectively.

CONCLUSION

MXA using a 33-point technique developed for adults is not a reliable method for the identification of mild vertebral fractures in children. A pediatric standard is required which not only incorporates specific vertebral body height ratios but also the age-related physiological changes in vertebral shape that occur throughout childhood.

Are semi-automated software program designed for adults accurate for the identification of vertebral fractures in children?

Objectives

To assess whether diagnostic accuracy of morphometric vertebral fracture (VF) diagnosis in children can be improved using AVERT™ (a 33-point semi-automated program developed for VF diagnosis in adults) compared with SpineAnalyzer™ (a 6-point program), which has previously been shown to be of insufficient accuracy.

Materials and methods

Lateral spine radiographs (XR) and dual-energy X-ray absorptiometry (DXA) scans of 50 children and young people were analysed by two observers using two different programs (AVERT™ and SpineAnalyzer™). Diagnostic accuracy (sensitivity, specificity, false-negative (FN) and false-positive rates (FP)) was calculated by comparing with a previously established consensus arrived at by three experienced paediatric musculoskeletal radiologists, using a simplified algorithm-based qualitative scoring system. Observer agreement was calculated using Cohen’s kappa.

Results

For XR, overall sensitivity, specificity, FP and FN rates using AVERT™ were 36%, 95%, 5% and 64% respectively and 26%, 98%, 2% and 75% respectively, using SpineAnalyzer™. For DXA, overall sensitivity, specificity, FP and FN rates using AVERT™ were 41%, 91%, 9% and 59% respectively and 31%, 96%, 4% and 69% respectively, using SpineAnalyzer. Reliability (kappa) ranged from 0.34 to 0.37 (95%CI, 0.26–0.46) for AVERT™ and from 0.26 to 0.31 (95%CI, 0.16–0.44) for SpineAnalyzer™. Inter- and intra-observer agreement ranged from 0.41 to 0.47 for AVERT™ and from 0.50 to 0.79 for SpineAnalyzer™.

Conclusion

AVERT™ has slightly higher accuracy but lower observer reliability for the representation of vertebral morphometry in children when compared with SpineAnalyzer™. However, neither software program is satisfactorily reliable for VF diagnosis in children.

Key Points

• SpineAnalyzer™ and AVERT™ have low diagnostic accuracy and observer agreement when compared to three paediatric radiologists’ readings for the diagnosis of vertebral fractures (VF) in children.

• Neither AVERT™ nor SpineAnalyzer™ is satisfactorily reliable for VF diagnosis in children.

• Development of specific paediatric software and normative values (incorporating age-related physiological variation in children) is required.

Radiation exposure in adult and pediatric patients with osteogenesis imperfecta

Diagnostic radiographs, computed tomography (CT), nuclear medicine studies, and intraoperative fluoroscopy durations were analyzed for radiation exposure. Cumulative and yearly effective ionizing radiation doses, cumulative background radiation, and total radiograph studies were compared between pediatric and adult populations. In 24 patients with 1,246 imaging studies (average 5.5 years longitudinal treatment duration), the mean estimated cumulative effective radiation dose per patient was 30.0 mSv (range 2.3-115.0), with an average yearly dose of 4.9 mSv (range 0.4-24.8). Pediatric patients had significantly more radiograph studies per year than adults and greater average yearly effective radiation doses.

Diagnosis of osteoporotic vertebral fractures in children

Osteoporosis is a generalised disorder of the skeleton with reduced bone density and abnormal bone architecture. It increases bone fragility and renders the individual susceptible to fractures. Fractures of the vertebrae are common osteoporotic fractures. Vertebral fractures may result in scoliosis or kyphosis and, because they may be clinically silent, it is imperative that vertebral fractures are diagnosed in children accurately and at an early stage, so the necessary medical care can be implemented. Traditionally, diagnosis of osteoporotic vertebral fractures has been from lateral spine radiographs; however, a small number of studies have shown that dual energy x-ray absorptiometry is comparable to radiographs for identifying vertebral fractures in children, while allowing reduced radiation exposure. The diagnosis of vertebral fractures from dual energy x-ray absorptiometry is termed vertebral fracture assessment. Existing scoring systems for vertebral fracture assessment in adults have been assessed for use in children, but there is no standardisation and observer reliability is variable. This literature review suggests the need for a semiautomated tool that (compared to the subjective and semiquantitative methods available) will allow more reliable and precise detection of vertebral fractures in children.

Evaluation of high resolution thermal imaging to determine the effect of vertebral fractures on associated skin surface temperature in children with osteogenesis imperfecta

Vertebral fractures are common in children with osteogenesis imperfecta (OI). Current imaging methods for fracture detection (X-ray and DXA) use ionising radiation. This pilot study explored whether the alteration in blood flow in vertebral fractures results in skin temperature changes that may be detected using high resolution thermal imaging (HRTI) and thus assist diagnosis and monitoring of fractures in OI patients. Eleven participants aged 5-18 years with OI and known vertebral fractures were enrolled. Small metal discs were placed on the skin surface alongside the vertebrae before participants had DXA and X-ray scans and thermal imaging of their backs. Visibility of the discs on the DXA and X-ray scans and thermal images allowed the temperatures of the skin surface above vertebrae without (healthy) and with fractures to be compared to their respective adjacent skin surface regions (region of reference, ROR) by calculating the temperature percentage change (TPC). The TPC between the skin temperature over the fractured thoracic vertebrae (n = 11) and the ROR was significant (1.44%, p = 0.002, 95% confidence). TPC between the skin temperature over healthy thoracic vertebrae and ROR was not significant (0.97%, p = 0.15, 95% confidence). HRTI may provide a novel tool for assisting in detection of vertebral fractures in OI. Graphical abstract • Patients (aged 5-18) with osteogenesis imperfecta and known vertebral fractures. • Thermal imaging was performed alongside routine imaging (DXA scan and spinal X-ray). • The temperature above each vertebra was compared with its adjacent skin region to assist with diagnosis of the fracture.

Health-Related Quality of Life in Adults with Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a systemic connective tissue disorder most often caused by mutations in collagen type 1 related genes. Patients with OI suffer from multiple fractures and various degrees of growth deficiency and bone deformity. It is unknown whether the systemic effect of defect collagen type 1 influences the quality of life in patients with OI. We therefore aimed to investigate health-related quality of life (HRQoL) in a well-characterized cohort of adult patients with OI. We included 85 adult patients with mild to severe OI (types I, III, and IV) and obtained information about skeletal- and non-skeletal phenotypes and patient demographics. We investigated physical and mental HRQoL using a validated questionnaire, SF-36, and compared the data to values obtained in a population without OI. Patients with mild, moderate, and severe OI all had lower mean scores on domains describing physical HRQoL and a lower mean physical component score compared to the general population, p < 0.001. Patients with severe OI had lower mean scores on physical HRQoL, p < 0.05. The scores on domains reflecting mental HRQoL were more inhomogenously affected, but did not differ significantly from the general population. OI has an impact on physical and some aspects of mental HRQoL. The scores on physical health were correlated to severity of the OI disease. The mental component score in the OI patients was unaffected and comparable with the general population.

Osteogenesis Imperfecta

Osteogenesis imperfecta is a common heritable connective tissue disorder. Nearly ninety percent are due to Type I collagen mutations. Type I-IV are autosomal dominant, and Type VI-XIII are autosomal recessive. They are Graded 1-5 based on severity. Genomic testing is done by collagen analysis from fibroblasts. The mainstay of treatment is bisphosphonate therapy. The prognosis is variable.

Developmental charts for children with osteogenesis imperfecta, type I (body height, body weight and BMI)

Osteogenesis imperfecta (OI) is a rare genetic disorder of type I collagen. Type I is the most common, which is called a non-deforming type of OI, as in this condition, there are no major bone deformities. This type is characterised by blue sclera and vertebral fractures, leading to mild scoliosis. The body height of these patients is regarded as normal, or only slightly reduced, but there are no data proving this in the literature. The aim of this study is the preparation of the developmental charts of children with OI type I. The anthropometric data of 117 patients with osteogenesis imperfecta were used in this study (61 boys and 56 girls). All measurements were pooled together into one database (823 measurements in total). To overcome the problem of the limited number of data being available in certain age classes and gender groups, the method called reverse transformation was used. The body height of the youngest children, aged 2 and 3 years, is less than that of their healthy peers. Children between 4 and 7 years old catch up slightly, but at later ages, development slows down, and in adults, the median body height shows an SDS of -2.7.

CONCLUSION

These results show that children with type I OI are smaller from the beginning than their healthy counterparts, their development slows down from 8 years old, and, ultimately, their body height is impaired. What is Known: • The body height of patients with osteogenesis imperfecta type I is regarded as normal, or only slightly reduced, but in the known literature, there is no measurement data supporting this opinion. What is New: • Children with type I osteogenesis imperfecta are smaller from the beginning than their healthy counterparts, their development slows down from 8 years old and, ultimately, their final body height is impaired. • The developmental charts for the body height, body weight and BMI of children with type I osteogenesis imperfecta are shown.

Prevalence of Vertebral Fractures in Children with Suspected Osteoporosis

OBJECTIVES

To explore the prevalence and anatomic distribution of vertebral fractures in disease groups investigated for primary and secondary osteoporosis, using vertebral fracture assessment (VFA).

STUDY DESIGN

VFA was performed independently by 2 nonradiologists, in 165 children (77 males, 88 females) as part of their investigation for osteoporosis. Vertebral bodies from T6 to L4 were assessed for vertebral fractures using the Genant scoring system. The common readings for the presence of vertebral fractures were used for evaluating the prevalence and anatomic distribution of vertebral fractures.

RESULTS

The median age of the subjects was 13.4 years (range, 3.6, 18). Of the 165 children, 24 (15%) were being investigated for primary bone disease, and the remainder had a range of chronic diseases known to affect bone health. Vertebral fractures were identified in 38 (23%) children. The distribution of the vertebral fractures was bimodal, with vertebral fractures peaks centered at T9 and L4. Conditions associated with increased odds for vertebral fractures were inflammatory bowel disease (OR, 3.3; 95% CI, 1.4, 8.0; P = .018) and osteogenesis imperfecta (OR, 2.3; 95% CI, 1.04, 5.8; P = .022). Among children with vertebral fractures, those with Duchenne muscular dystrophy (P = .015) and osteogenesis imperfecta (P = .023) demonstrated higher number of vertebral fractures than the other disease groups.

CONCLUSIONS

VFA identified the presence of vertebral fractures, in a bimodal distribution, in both primary bone disease and chronic disease groups. VFA is a practical screening tool for identification of vertebral fractures in children and adolescents at risk of fragility fractures.

A novel homozygous variant in SERPINH1 associated with a severe, lethal presentation of osteogenesis imperfecta with hydranencephaly

Osteogenesis imperfecta (OI) is a genetic disorder characterised by low bone mineral density resulting in fractures. 85-90% of patients with OI carry a variant in the type 1 collagen genes, COL1A1 and COL1A2, which follows an autosomal dominant pattern of inheritance. However, within the last two decades, there have been growing number of variants identified in genes that follow an autosomal recessive pattern of inheritance. Our proband is a child born in Mexico with multiple fractures of ribs, minimal calvarial mineralisation, platyspondyly, marked compression and deformed long bones. He also presented with significant hydranencephaly, requiring ventilatory support from birth, and died at 8days of age. A homozygous c.338_357delins22 variant in exon 2 of SERPINH1 was identified. This gene encodes heat shock protein 47, a collagen-specific chaperone which binds to the procollagen triple helix and is responsible for collagen stabilisation in the endoplasmic reticulum. There is minimal literature on the mechanism of action for variants in SERPINH1 resulting in osteogenesis imperfecta. Here we discuss this rare, previously unreported variant, and expand on the phenotypic presentation of this novel variant resulting in a severe, lethal phenotype of OI in association with hydranencephaly.

Efficacy and Safety of Bisphosphonate Therapy in Children with Osteogenesis Imperfecta: A Systematic Review

BACKGROUND/AIMS

To systematically assess contemporary knowledge regarding the effectiveness and safety of bisphosphonates (BPs) in children with osteogenesis imperfecta (OI).

METHODS

PubMed/MEDLINE, Embase, and Cochrane were searched for eligible articles up to June 2014. Studies eligible for inclusion were (randomized) controlled trials assessing the effects of BPs in children with OI. Methodological quality was assessed independently by 4 reviewers using the Cochrane Collaboration's tool for risk of bias.

RESULTS

Ten studies (519 children) were included. Four studies (40%) showed a low risk of bias. All studies investigating lumbar spine areal bone mineral density indicated a significant increase as a result of BP treatment. Most studies observed a significant decrease in fracture incidence. The most frequently reported adverse events were gastrointestinal complaints, fever, and muscle soreness. A significant decrease in (bone) pain due to BP treatment was observed in more than half of the studies. Most studies measuring urinary markers of bone resorption reported a significant decrease. The majority of studies with intravenous treatment showed a significant increase in lumbar projection area, whereas studies with oral treatment did not.

CONCLUSIONS

Treatment with oral or intravenous BPs in children with OI results in an increase in bone mineral density and seems to be safe and well tolerated.

10-m Shuttle Ride Test in Youth With Osteogenesis Imperfecta Who Use Wheelchairs: Feasibility, Reproducibility, and Physiological Responses

BACKGROUND

Physical fitness levels in youth with osteogenesis imperfecta (OI) who use wheelchairs are unknown. The 10-m Shuttle Ride Test (SRiT) has recently been introduced as a field test to determine cardiorespiratory fitness in children with cerebral palsy who self-propel a wheelchair.

OBJECTIVE

The purpose of this study was to investigate the feasibility and reproducibility of the SRiT, as well as the physiological responses to the SRiT, in youth with moderate-to-severe OI between 8 and 25 years of age who self-propel a wheelchair at least for long distances.

DESIGN

A test-retest design was used.

METHODS

Thirteen patients with OI (8 boys, 5 girls; mean±SD values for age=15.5±6.4 years) using a manual wheelchair performed 2 SRiTs within 2 weeks. Adverse events, reached stage, peak heart rate (HRpeak), peak respiratory exchange ratio (RERpeak), peak oxygen uptake (V̇o2peak), and peak minute ventilation (V̇epeak) were the main outcome parameters.

RESULTS AND DISCUSSION

All participants performed a maximal effort at both SRiTs (mean±SD values for HRpeak of 195±9 beats per minute [bpm], RERpeak of 1.32±0.16, V̇o2peak of 25.4±5.6 mL·kg(-1)·min(-1), and V̇epeak of 47.9±18.6 L·min(-1)), without adverse events. The intraclass correlation coefficient of the reached stage showed excellent reliability (.95). Limits of agreement (LoA) analysis revealed acceptable LoA for reached stage (mean bias=-0.58, range=-2.50 to +1.35). There was a low correlation between reached stage and V̇o2peak (r=.61 and r=.45 for the first and second SRiTs, respectively).

LIMITATIONS

The influence of wheelchair properties and individually adjusted wheelchair designs was not examined.

CONCLUSIONS

The SRiT appears to be a feasible, safe, and reproducible maximal field test in youth with OI using wheelchairs at least for long distances. This field test might be useful to provide an indication of physical fitness and to assess the efficacy of interventions on physical fitness in these patients.

Health outcomes of neonates with osteogenesis imperfecta: a cross-sectional study

OBJECTIVE

To assess at-birth health outcomes of neonates with osteogenesis imperfecta (OI).

STUDY DESIGN

A total of 53 women who self-reported having had at least one child with OI completed the survey. We evaluated pregnancy length, neonatal intensive care unit (NICU) usage, at-birth complications, and the child's clinical information including OI type, height and weight.

RESULTS

Information was gathered on a total of 77 children (60 type I, 4 type III and 13 type IV). Health conditions reported at birth included breech presentation (24%), prematurity (27%), fracture (18%), bone deformity (18%) and respiratory problems (22%). Approximately 31% (n = 24) received NICU care. There was a significant association between younger maternal age, preterm delivery and NICU admission.

CONCLUSION

Our findings suggest that newborns with OI appear to be at high risk of skeletal disorders, preterm delivery and breech presentation. Younger maternal age and preterm delivery seem to be strong predictors of the need for NICU care. Our data suggest that pregnant women with OI younger than 20 years of age may benefit from added clinical supervision in anticipation of adverse effects on their child.

Bisphosphonates: Pharmacokinetics, bioavailability, mechanisms of action, clinical applications in children, and effects on tooth development

Bisphosphonates (BPs) avidly bind to calcium crystals and inhibit osteoclastic bone resorption, making them useful for treatment of skeletal disorders such as osteoporosis, Paget's disease, osteogenesis imperfecta and metastatic bone diseases. BPs therapeutically act by causing toxic effects on osteoclasts or interfering with specific intracellular pathways in those cells. BPs that possess nitrogen in their composition are called nitrogen-containing BPs (NBPs) and include alendronate, pamidronate, risedronate, ibandronate, and zoledronate. Simple BPs or non-NBPs do not have nitrogen in their composition, include etiodronate and clodronate, and were the first to be tested in animals and clinically used. Because BPs may be administered to pregnant women or children during deciduous and permanent teeth development, it is expected that they might disturb tooth eruption and development. A review of current literature on pharmacokinetics, bioavailability, mechanisms of action, and clinical applications of BPs in children, and their effects on tooth eruption and development is presented.

A critical appraisal of vertebral fracture assessment in paediatrics

PURPOSE

There is a need to improve our understanding of the clinical utility of vertebral fracture assessment (VFA) in paediatrics and this requires a thorough evaluation of its readability, reproducibility, and accuracy for identifying VF.

METHODS

VFA was performed independently by two observers, in 165 children and adolescents with a median age of 13.4 years (range, 3.6, 18). In 20 of these subjects, VFA was compared to lateral vertebral morphometry assessment on lateral spine X-ray (LVM).

RESULTS

1528 (84%) of the vertebrae were adequately visualised by both observers for VFA. Interobserver agreement in vertebral readability was 94% (kappa, 0.73 [95% CI, 0.68, 0.73]). 93% of the non-readable vertebrae were located between T6 and T9. Interobserver agreement per-vertebra for the presence of VF was 99% (kappa, 0.85 [95% CI, 0.79, 0.91]). Interobserver agreement per-subject was 91% (kappa, 0.78 [95% CI, 0.66, 0.87]). Per-vertebra agreement between LVM and VFA was 95% (kappa 0.79 [95% CI, 0.62, 0.92]) and per-subject agreement was 95% (kappa, 0.88 [95% CI, 0.58, 1.0]). Accepting LVM as the gold standard, VFA had a positive predictive value (PPV) of 90% and a negative predictive value (NPV) of 95% in per-vertebra analysis and a PPV of 100% and NPV of 93% in per-subject analysis.

CONCLUSION

VFA reaches an excellent level of agreement between observers and a high level of accuracy in identifying VF in a paediatric population. The readability of vertebrae at the mid thoracic region is suboptimal and interpretation at this level should be exercised with caution.

Classification of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is an extremely heterogeneous group of heritable connective tissue disorders. Most of the affected patients carry autosomal dominant mutations in the genes encoding for collagen type I, the most abundant protein of the bone extracellular matrix. The resulting phenotypes are extremely broad and have been classified by Sillence and colleagues into four groups according to clinical, radiological and genetic criteria.More recently, proteins have been described that interact directly or indirectly with collagen biosynthesis and their deficiency result in rare forms of mostly autosomal recessive OI sharing phenotypic features of 'classical' types but lacking primary defects in type I collagen. Consequently the Sillence classification has been gradually expanded to include novel forms based on the underlying mutations. The goal of this article is to revisit the actual OI classification and to outline current approaches in categorizing the disorder.

The use of bisphosphonates in pediatrics

Bisphosphonates are widely used for the prevention and treatment of osteoporosis in adulthood. In the last years, bisphosphonates have been increasingly used in pediatric patients for the treatment of a growing number of disorders associated with osteoporosis, resistant hypercalcemia or heterotopic calcifications. The use of bisphosphonates in pediatric patients has been proven safe; however, the risk of potential severe consequences into adulthood should be kept in mind. Well-defined criteria for bisphosphonates treatment in pediatric patients are not specified, therefore an accurate selection of patients who could benefit from bisphosphonates is mandatory. A strict follow-up of pediatric patients receiving long-term bisphosphonate therapy is strongly recommended. The purpose of this mini review is to provide a summary of current knowledge on some main general aspects of the structure, mechanisms of action, pharmacokinetics, and bioavailability of bisphosphonates, and to focus on the latest advances of bisphosphonate treatment in pediatric patients. Particular attention has been paid to the common and potential adverse effects of bisphosphonate treatment, and some suggestions concerning the clinical approach and general measures for bisphosphonate treatment in pediatric patients are reported.

Stem cell transplantation before birth - a realistic option for treatment of osteogenesis imperfecta?

Osteogenesis imperfecta (OI) is characterized by severe bone deformities, growth retardation and bones that break easily, often from little or no apparent cause. OI is a genetic disorder primarily with defective type I collagen with a wide spectrum of clinical expression. In the more severe cases, it can be diagnosed before birth. Transplantation of mesenchymal stem cells (MSC) has the potential to improve the bone structure and stability, growth and fracture healing. Prenatal and postnatal cell transplantation has been investigated in preclinical and clinical studies of OI and suggests that this procedure is safe and has positive effects. Cell transplantation resulted in improved linear growth, mobility and reduced fracture incidence. However, the effect is transient and for this reason re-transplantation may be needed. So far there is limited experience in this area, and proper studies are required to accurately determine if MSC transplantation is of clinical benefit in the treatment of OI. In this review, we summarize what is currently known in this field.

Clinical application of antenatal genetic diagnosis of osteogenesis imperfecta type IV

Background

Clinical analysis and genetic testing of a family with osteogenesis imperfecta type IV were conducted, aiming to discuss antenatal genetic diagnosis of osteogenesis imperfecta type IV.

Material/Methods

Preliminary genotyping was performed based on clinical characteristics of the family members and then high-throughput sequencing was applied to rapidly and accurately detect the changes in candidate genes.

Results

Genetic testing of the III5 fetus and other family members revealed missense mutation in c.2746G>A, pGly916Arg in COL1A2 gene coding region and missense and synonymous mutation in COL1A1 gene coding region.

Conclusions

Application of antenatal genetic diagnosis provides fast and accurate genetic counseling and eugenics suggestions for patients with osteogenesis imperfecta type IV and their families.

Caries in adolescents in relation to their skeletal status

OBJECTIVE

Despite well-known evidence of association of caries with bone metabolic diseases, there are only a small number of studies about caries and bone mineral density (BMD) on pediatric population. We evaluated the possibility of bone mineralization and metabolism disturbances in children with caries and compared them with healthy individuals.

MATERIALS AND METHODS

A total of 123 patients with caries (63 boys and 60 girls), aged 12-15 years, were included. The children were divided according caries stage: the decayed, missing, and filled tooth (DMFT) group (n=73) and the initial caries (IC) group (n=50), which have clinically active initial caries lesions on the enamel ("white spots"). Caries-free (CF) children (n=42) were the healthy controls. Bone mineralization was measured in all children with caries and healthy controls by dual-energy X-ray absorptiometry of the lumbar spine (L1-L4). For the assessment of bone metabolism, osteocalcin, carboxy terminal telopeptide of type I collagen (CTX), parathyroid hormone, Ca²⁺, inorganic phosphate, and total alkaline phosphatase were used.

RESULTS

Children with DMFT have low BMD and BMD Z score in association with low osteocalcin and high CTX levels, compared with IC (p=0.008 and p=0.0001, respectively) and CF children (p<0.0000 and p=0.0001, respectively). In DMFT, Ca²⁺ was significantly higher compared with IC (p=0.01) and CF (p=0.003). Caries stages negatively correlated with BMD (r=-0.86, p<0.001). A differently directed correlation between CTX and osteocalcin was detected: CTX was negatively related to osteocalcin in the DMFT group (r=-0.22, p=0.043) and positively related in the IC (r=0.42, p=0.002) and CF children (r=0.58, p=0.0000).

CONCLUSIONS

Children with any caries stage have decreased BMD accompanied with increased bone resorption. We consider that caries could be a marker of impact bone mineralization and metabolism.

Cranial base pathology in pediatric osteogenesis imperfecta patients treated with bisphosphonates

OBJECT

Cranial base pathology is a serious complication of osteogenesis imperfecta (OI). Our aim was to analyze whether bisphosphonate treatment, used to improve bone strength, could also prevent the development of craniocervical junction pathology (basilar impression, basilar invagination, or platybasia) in children with OI.

METHODS

In this single-center retrospective study the authors analyzed the skull base morphology from lateral skull radiographs and midsagittal MR images (total of 94 images), obtained between the ages of 0 and 25 years in 39 bisphosphonate-treated OI patients. The results were compared with age-matched normative values and with findings in 70 OI patients who were not treated with bisphosphonates. In addition to cross-sectional data, longitudinal data were available from 22 patients with an average follow-up period of 7.6 years. The patients, who had OI types I, III, IV, VI, and VII, had been treated with zoledronic acid, pamidronate, or risedronate for 3.2 years on average.

RESULTS

Altogether 33% of the 39 bisphosphonate-treated patients had at least 1 cranial base anomaly, platybasia being the most prevalent diagnosis (28%). Logistic regression analysis suggested a higher risk of basilar impression or invagination in patients with severe OI (OR 22.04) and/or older age at initiation of bisphosphonate treatment (OR 1.45), whereas a decreased risk was associated with longer duration of treatment (OR 0.28). No significant associations between age, height, or cumulative bisphosphonate dose and the risk for cranial base anomaly were detected. In longitudinal evaluation, Kaplan-Meier curves suggested delayed development of cranial base pathology in patients treated with bisphosphonates but the differences from the untreated group were not statistically significant.

CONCLUSIONS

These findings indicate that cranial base pathology may develop despite bisphosphonate treatment. Early initiation of bisphosphonate treatment may delay development of craniocervical junction pathology. Careful followup of cranial base morphology is warranted, particularly in patients with severe OI.

Osteogenesis imperfecta types I-XI: implications for the neonatal nurse

Osteogenesis imperfecta (OI), also called "brittle bone disease," is a rare heterozygous connective tissue disorder that is caused by mutations of genes that affect collagen. Osteogenesis imperfecta is characterized by decreased bone mass, bone fragility, and skin hyperlaxity. The phenotype present is determined according to the mutation on the affected gene as well as the type and location of the mutation. Osteogenesis imperfecta is neither preventable nor treatable. Osteogenesis imperfecta is classified into 11 types to date, on the basis of their clinical symptoms and genetic components. This article discusses the definition of the disease, the classifications on the basis of its clinical features, incidence, etiology, and pathogenesis. In addition, phenotype, natural history, diagnosis and management of this disease, recurrence risk, and, most importantly, the implications for the neonatal nurse and management for the family are discussed.

[Osteogenesis imperfecta]

BACKGROUND

Osteogenesis imperfecta (OI) is the most common genetic disease of bone and is characterized by fragile bones and growth disorders of varying severity. Most cases of OI are inherited autosomal dominant and caused by a mutation in the collagen type I gene.

DIAGNOSTICS

Indications for OI are bone fragility, stunted growth, scoliosis, skull deformities, blue sclera, loss of hearing, dentinogenesis imperfecta and increased laxity of ligaments and skin. In most cases it is possible to make a clinical diagnosis but a skin biopsy or genetic testing can be useful; however, negative results for these tests do not exclude OI.

THERAPY

Therapy must be carried out in a multidisciplinary team and includes conservative (e.g. physiotherapy, rehabilitation programs and orthopedic aids), operative (e.g. intramedullary stabilization procedures) and pharmaceutical (e.g. biphosphonates and growth hormones) procedures.

PROGNOSIS

The prognosis depends on the type of OI and ranges from normal life expectations for type 1 patients up to up to perinatal mortality for type II patients.

Pre- and postnatal transplantation of fetal mesenchymal stem cells in osteogenesis imperfecta: a two-center experience

Osteogenesis imperfecta (OI) can be recognized prenatally with ultrasound. Transplantation of mesenchymal stem cells (MSCs) has the potential to ameliorate skeletal damage. We report the clinical course of two patients with OI who received prenatal human fetal MSC (hfMSC) transplantation and postnatal boosting with same-donor MSCs. We have previously reported on prenatal transplantation for OI type III. This patient was retransplanted with 2.8 × 10(6) same-donor MSCs per kilogram at 8 years of age, resulting in low-level engraftment in bone and improved linear growth, mobility, and fracture incidence. An infant with an identical mutation who did not receive MSC therapy succumbed at 5 months despite postnatal bisphosphonate therapy. A second fetus with OI type IV was also transplanted with 30 × 10(6) hfMSCs per kilogram at 31 weeks of gestation and did not suffer any new fractures for the remainder of the pregnancy or during infancy. The patient followed her normal growth velocity until 13 months of age, at which time longitudinal length plateaued. A postnatal infusion of 10 × 10(6) MSCs per kilogram from the same donor was performed at 19 months of age, resulting in resumption of her growth trajectory. Neither patient demonstrated alloreactivity toward the donor hfMSCs or manifested any evidence of toxicities after transplantation. Our findings suggest that prenatal transplantation of allogeneic hfMSCs in OI appears safe and is of likely clinical benefit and that retransplantation with same-donor cells is feasible. However, the limited experience to date means that it is not possible to be conclusive and that further studies are required.

Risedronate in children with osteogenesis imperfecta: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Children with osteogenesis imperfecta are often treated with intravenous bisphosphonates. We aimed to assess the safety and efficacy of risedronate, an orally administered third-generation bisphosphonate, in children with the disease.

METHODS

In this multicentre, randomised, parallel, double-blind, placebo-controlled trial, children aged 4-15 years with osteogenesis imperfecta and increased fracture risk were randomly assigned by telephone randomisation system in a 2:1 ratio to receive either daily risedronate (2·5 or 5 mg) or placebo for 1 year. Study treatment was masked from patients, investigators, and study centre personnel. Thereafter, all children received risedronate for 2 additional years in an open-label extension. The primary efficacy endpoint was percentage change in lumbar spine areal bone mineral density (BMD) at 1 year. The primary efficacy analysis was done by ANCOVA, with treatment, age group, and pooled centre as fixed effects, and baseline as covariate. Analyses were based on the intention-to-treat population, which included all patients who were randomly assigned and took at least one dose of assigned study treatment. The trial is registered with ClinicalTrials.gov, number NCT00106028.

FINDINGS

Of 147 patients, 97 were randomly assigned to the risedronate group and 50 to the placebo group. Three patients from the risedronate group and one from the placebo group did not receive study treatment, leaving 94 and 49 in the intention-to-treat population, respectively. The mean increase in lumbar spine areal BMD after 1 year was 16·3% in the risedronate group and 7·6% in the placebo group (difference 8·7%, 95% CI 5·7-11·7; p<0·0001). After 1 year, clinical fractures had occurred in 29 (31%) of 94 patients in the risedronate group and 24 (49%) of 49 patients in the placebo group (p=0·0446). During years 2 and 3 (open-label phase), clinical fractures were reported in 46 (53%) of 87 patients in the group that had received risedronate since the start of the study, and 32 (65%) of 49 patients in the group that had been given placebo during the first year. Adverse event profiles were otherwise similar between the two groups, including frequencies of reported upper-gastrointestinal and selected musculoskeletal adverse events.

INTERPRETATION

Oral risedronate increased areal BMD and reduced the risk of first and recurrent clinical fractures in children with osteogenesis imperfecta, and the drug was generally well tolerated. Risedronate should be regarded as a treatment option for children with osteogenesis imperfecta.

FUNDING

Alliance for Better Bone Health (Warner Chilcott and Sanofi).

Bone geometry, density, and microarchitecture in the distal radius and tibia in adults with osteogenesis imperfecta type I assessed by high-resolution pQCT

Osteogenesis imperfecta (OI) is a hereditary disorder characterized by decreased biosynthesis or impaired morphology of type I collagen that leads to decreased bone mass and increased bone fragility. We hypothesized that patients with OI have altered bone microstructure and bone geometry. In this cross-sectional study we compared patients with type I OI to age- and gender-matched healthy controls. A total of 39 (13 men and 26 women) patients with OI, aged 53 (range, 21-77) years, and 39 controls, aged 53 (range, 21-77) years, were included in the study. Twenty-seven of the patients had been treated with bisphosphonates. High-resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and distal tibia and dual-energy X-ray absorptiometry of total hip, femoral neck, trochanteric region, and the lumbar spine (L1-L4) were performed. The patients were shorter than the controls (159 ± 10 cm versus 170 ± 9 cm, p < 0.001), but had similar body weight. In OI, areal bone mineral density (aBMD) was 8% lower at the hip (p < 0.05) and 13% lower at the spine (p < 0.001) compared with controls. The trabecular volumetric bone mineral density (vBMD) was 28% lower in radius (p < 0.001) and 38% lower in tibia (p < 0.001) in OI compared with controls. At radius, total bone area was 5% lower in OI than in controls (p < 0.05). In the tibia, cortical bone area was 18% lower in OI (p < 0.001). In both radius and tibia the number of trabeculae was lower in patients compared to the controls (35% and 38%, respectively, p < 0.001 at both sites). Furthermore, trabecular spacing was 55% higher in OI in both tibia and radius (p < 0.001 at both sites) when compared with controls. We conclude that patients with type I OI have lower aBMD, vBMD, bone area, and trabecular number when compared with healthy age- and gender-matched controls.

New perspectives on osteogenesis imperfecta

A new paradigm has emerged for osteogenesis imperfecta as a collagen-related disorder. The more prevalent autosomal dominant forms of osteogenesis imperfecta are caused by primary defects in type I collagen, whereas autosomal recessive forms are caused by deficiency of proteins which interact with type I procollagen for post-translational modification and/or folding. Factors that contribute to the mechanism of dominant osteogenesis imperfecta include intracellular stress, disruption of interactions between collagen and noncollagenous proteins, compromised matrix structure, abnormal cell-cell and cell-matrix interactions and tissue mineralization. Recessive osteogenesis imperfecta is caused by deficiency of any of the three components of the collagen prolyl 3-hydroxylation complex. Absence of 3-hydroxylation is associated with increased modification of the collagen helix, consistent with delayed collagen folding. Other causes of recessive osteogenesis imperfecta include deficiency of the collagen chaperones FKBP10 or Serpin H1. Murine models are crucial to uncovering the common pathways in dominant and recessive osteogenesis imperfecta bone dysplasia. Clinical management of osteogenesis imperfecta is multidisciplinary, encompassing substantial progress in physical rehabilitation and surgical procedures, management of hearing, dental and pulmonary abnormalities, as well as drugs, such as bisphosphonates and recombinant human growth hormone. Novel treatments using cell therapy or new drug regimens hold promise for the future.