Hearing loss in Finnish adults with osteogenesis imperfecta: a nationwide survey

Hearing impairment amongst people with Osteogenesis Imperfecta in Germany

INTRODUCTION

Hearing impairment concerns a relevant percentage of individuals with Osteogenesis Imperfecta (OI). When looking at the current literature, the percentage of affected individuals with OI varies greatly from 32 to 58% of patients having mild OI and 21% to 27% of patients having moderate to severe OI. Little is known about the German population with OI.

METHOD

The goal of this study was to detect how many patients with OI, who visited the annual meeting of the German Association for Osteogenesis Imperfecta in 2023, proved to have a hearing impairment. In this prospective, cross-sectional study, each included individual obtained ear microscopy, audiometry, stapedius reflexes, tympanometry, and OAEs. Furthermore, each patient was asked a set of questions concerning the medical history.

RESULTS

Of the included patients, 33% had hearing impairment. A significant difference was found for the mean air-bone gap (ABG) as well as the hearing threshold of the right ears. The difference was found between OI type III and IV (p = 0.0127) for the mean ABG and OI type I and IV (p = 0.0138) as well as III and IV (p = 0.0281) for the hearing threshold. Spearman's rank correlation showed a high correlation between age and hearing threshold. Of the patients between 40 and 50 years old, 56% had hearing loss.

CONCLUSION

Hearing loss in individuals with OI is still a relevant problem, especially age-related in OI type I. Audiometry should be performed at least when individuals experience subjective hearing loss. The implementation of a screening starting at 40 years should be discussed and studied.

Annual hearing screening in children with osteogenesis imperfecta: Results from the first five years in glasgow

BACKGROUND

Hearing loss is common in people with osteogenesis imperfecta (OI), although exactly how common is unknown. The prevalence of hearing loss in children with OI has been reported to be anything from 0 to 77 %. Brittle Bone Society guidelines suggest that, unless there are ear symptoms, children with OI should have their hearing tested every three years starting at age three. There is limited evidence to support this recommendation. We postulate that annual hearing screening would be easier to manage and would have a worthwhile pick-up rate.

METHODS

In March 2019 we began a programme of annual hearing screening for all children (ages 0-16) with OI. We collected data on age, genotype, otoscopy findings, tympanometry findings, audiometric test results and subsequent outcomes for the first five years of our programme (2019-2024).

RESULTS

Nineteen children with OI participated in the screening programme. Only one abnormality was found: a unilateral mild hearing impairment with a type B tympanogram, suggesting middle ear effusion. This was present in year 2 of the programme but resolved by year 3.

CONCLUSION

The screening programme has a low pickup rate (5 %) for new otological problems in the paediatric population. However, we believe that the low cost and small workload associated with the screening programme justifies continuing it until further conclusions can be drawn.

The PATCH study: Prevalence of Hearing Loss During Ageing and Treatment Choices in Osteogenesis Imperfecta: A Danish Nationwide Register-Based Cohort Study

Osteogenesis imperfecta (OI) is a group of rare hereditary collagen disorders. Hearing loss (HL) is a known complication linked to changes in the bones of the middle ear seen in OI. We aimed to determine the prevalence, age at debut, incidence, and risk of HL, surgery on bones of the middle ear, and use of hearing aids. A Danish nationwide, register-based cohort study. Data were extracted from the Danish National Patient register. Anyone with an OI diagnosis between January 1st 1977 and December 31st 2018, matched 1:5 with a reference population (Ref.Pop) on birthyear and sex, were included. 864 persons (487 women) with OI were included in the study and 4276 (2330 women) in the Ref.Pop. The sub-hazard ratio (SHR) for any HL was 4.56 [95% CI 3.64-5.71], with a prevalence of 17.0% and 4.0% in the OI cohort and Ref.Pop. Median age at debut was 42 and 58 years, respectively. The risk of otosclerosis and/or surgery was higher in the OI cohort (SHR 22.51 [95% CI 12.62-40.14]), with a median age at debut of 43 and 32 years in the OI cohort and Ref.Pop, respectively. Hearing aid use was more frequent in the OI cohort (SHR 4.16 [95% CI 3.21-5.40]) than in the Ref.Pop. The median age at debut was 45 and 60 years in the OI cohort and Ref.Pop, respectively. Persons with OI have a higher risk and prevalence of HL, hearing aids, and surgery, debuting younger, and prevalence increases with age.

Identification of a family with van der Hoeve's syndrome harboring a novel COL1A1 mutation and generation of patient-derived iPSC lines and CRISPR/Cas9-corrected isogenic iPSCs

Van der Hoeve's syndrome, also known as osteogenesis imperfecta (OI), is a genetic connective tissue disorder characterized by fragile, fracture-prone bone and hearing loss. The disease is caused by a gene mutation in one of the two type I collagen genes COL1A1 or COL1A2. In this study, we identified a novel frameshift mutation of the COL1A1 gene (c.1607delG) in a family with OI using whole-exome sequencing, bioinformatics analysis and Sanger sequencing. This mutation may lead to the deletion of a portion of exon 23 and the generation of a premature stop codon in the COL1A1 gene. To further investigate the impact of this mutation, we established two induced pluripotent stem cell (iPSC) lines from peripheral blood mononuclear cells of OI patients carrying a novel mutation in the COL1A1 gene. Osteoblasts (OB) derived from OI-iPSCs exhibited reduced production of type I collagen and diminished ability to differentiate into osteoblasts. Using a CRISPR-based homology-directed repair strategy, we corrected the OI disease-causing COL1A1 novel mutations in iPSCs generated from an affected individual. Our results demonstrated that the diminished expression of type I collagen and osteogenic potential were enhanced in OB induced from corrected OI-iPSCs compared to those from OI-iPSCs. Overall, our results provide new insights into the genetic basis of Van der Hoeve's syndrome and highlight the potential of iPSC technology for disease modeling and therapeutic development.

The IMPACT survey: a mixed methods study to understand the experience of children, adolescents and adults with osteogenesis imperfecta and their caregivers

BACKGROUND

Osteogenesis imperfecta (OI) is a rare, heritable connective tissue disorder associated with a variety of symptoms, that affect individuals' quality of life (QoL) and can be associated with increased healthcare resource use. While some aspects of OI are well studied, others remain poorly understood. Therefore, the IMPACT survey aimed to elucidate the humanistic, clinical and economic burden of OI on individuals with OI, their families, caregivers and wider society.

METHODS

We developed an international mixed methods online survey in eight languages (fielded July-September 2021), aimed at adults (aged ≥ 18 years) or adolescents (aged ≥ 12-17 years) with OI, caregivers (with or without OI) of individuals with OI and other close relatives. All respondents provided data on themselves; caregivers additionally provided data on individuals in their care by proxy. Data were cleaned, coded, and analysed using the pandas Python software package and Excel.

RESULTS

IMPACT collected 2208 eligible questionnaires (covering 2988 individuals of whom 2312 had OI) including 1290 non-caregiver adults with OI, 92 adolescents with OI, 150 caregiver adults with OI, 560 caregivers for individuals with OI, 116 close relatives and 780 proxy care-recipients with OI. Most individuals with OI (direct or proxy) described their OI as moderate (41-52% across populations) and reported OI type 1 (33-38%). Pain (72-82%) was the most reported clinical condition experienced in the past 12 months and was also most frequently rated as severely or moderately impactful. Further, among adults, 67% reported fatigue, 47% scoliosis, and 46% sleep disturbance; in adolescents, fatigue affected 65%, scoliosis and other bone problems 60%, and mental health problems 46%; in children, fractures were common in 67%, fatigue in 47%, and dental problems in 46%.

CONCLUSION

IMPACT has generated an extensive dataset on the experience of individuals with OI, their caregivers and relatives. We found that, irrespective of age, individuals with OI experience numerous and evolving symptoms that affect their QoL; however, pain and fatigue are consistently present. Upcoming analyses will provide further insights into the economic impact, healthcare journey and caregiver wellbeing, aiming to contribute to improved treatment and care for the OI community.

The International Standard Set of Outcome Measures for the Assessment of Hearing in People with Osteogenesis Imperfecta

OBJECTIVE

The aim is to recommend a minimum standard set of clinician-reported outcome measures (CROMs) and patient-reported outcome measures (PROMs) on hearing for people with osteogenesis imperfecta (OI). This project is part of the larger "Key4OI" project initiated by the "Care4BrittleBones foundation" of which the goal is to improve quality of life of people with OI. Key4OI provides a standard set of outcome measures and covers a large set of domains affecting the well-being of people with OI.

METHODS

An international team of experts in OI, comprising specialists in audiological science, medical specialists, and an expert patient representative, used a modified Delphi consensus process to select CROMs and PROMs to evaluate hearing problems in people with OI. In addition, focus groups of people with OI identified key consequences of their hearing loss. These criteria were matched to categories of preselected questionnaires to select a PROM that matched their specific hearing-related concerns best.

RESULTS

Consensus on PROMs for adults and CROMs for adults and children was reached. The focus of the CROMs was on specific audiological outcome measures and standardized follow-up.

CONCLUSIONS

This project resulted in a clear consensus statement for standardization of hearing-related PROMs and CROMs and follow-up management of patients with OI. This standardization of outcome measurements will facilitate comparability of research and easier international cooperation in OI and hearing loss. Furthermore, it can improve standard of care in people with OI and hearing loss by incorporating the recommendations into care pathways.

Bone allografting: an original method for biological osteosynthesis and bone reinforcement in children with osteogenesis imperfecta

PURPOSE

Osteogenesis imperfecta (OI) is a genetic disorder responsible for various symptoms including deformities and frequent fractures. Bone allografting is poorly documented in this condition. The objective of this study was to describe our experience and assessments in a consecutive series of OI patients.

METHODS

Thirty-nine lower limb allograft procedures (28 femurs, 11 tibias) were performed in 26OI patients (mean age, 12.9 years). They were classified as type III of Sillence (17), type IV (6), and 3 recessive forms. The indications for surgery were correction of deformity (19), fracture (16), and non-union (4). In all cases, bone allografting was added to reinforce areas of fragility and in 28 cases for osteosynthesis to lock the rotations at the osteotomy site and to avoid screwed metallic plate. The duration of bone consolidation and allograft fusion was assessed. Complications and Gillette functional score were reported.

RESULTS

The mean follow-up was 6.7years (range, 2 to 10 years). On average, bone consolidation was achieved after 3.3 months and graft fusion after 7.7 months. No bone allograft-related complications were observed and there was any secondary displacement. The Gillette functional score was improved in 23 patients and stable in three cases. Complications were reported in two cases: one partial allograft resorption and one delayed consolidation of a non-union. One refracture was observed but after a significant trauma in a child who had regained significant physical activity.

CONCLUSIONS

Bone allografting in children with OI is a reliable method of biological fixation, allowing efficient fusion and contributing to increased bone capital and functional outcome.

The patient clinical journey and socioeconomic impact of osteogenesis imperfecta: a systematic scoping review

BACKGROUND

Osteogenesis imperfecta (OI) is a rare heritable connective tissue disorder primarily characterised by skeletal deformity and fragility, and an array of secondary features. The purpose of this review was to capture and quantify the published evidence relating specifically to the clinical, humanistic, and economic impact of OI on individuals, their families, and wider society.

METHODS

A systematic scoping review of 11 databases (MEDLINE, MEDLINE in-progress, EMBASE, CENTRAL, PsycINFO, NHS EED, CEA Registry, PEDE, ScHARRHUd, Orphanet and Google Scholar), supplemented by hand searches of grey literature, was conducted to identify OI literature published 1st January 1995-18th December 2021. Searches were restricted to English language but without geographical limitations. The quality of included records was assessed using the AGREE II checklist and an adapted version of the JBI cross-sectional study checklist.

RESULTS

Of the identified 7,850 records, 271 records of 245 unique studies met the inclusion criteria; overall, 168 included records examined clinical aspects of OI, 67 provided humanistic data, 6 reported on the economic impact of OI, and 30 provided data on mixed outcomes. Bone conditions, anthropometric measurements, oral conditions, diagnostic techniques, use of pharmacotherapy, and physical functioning of adults and children with OI were well described. However, few records included current care practice, diagnosis and monitoring, interactions with the healthcare system, or transition of care across life stages. Limited data on wider health concerns beyond bone health, how these concerns may impact health-related quality of life, in particular that of adult men and other family members, were identified. Few records described fatigue in children or adults. Markedly few records provided data on the socioeconomic impact of OI on patients and their caregivers, and associated costs to healthcare systems, and wider society. Most included records had qualitative limitations.

CONCLUSION

Despite the rarity of OI, the volume of recently published literature highlights the breadth of interest in the OI field from the research community. However, significant data gaps describing the experience of OI for individuals, their families, and wider society warrant further research to capture and quantify the full impact of OI.

[Features and results of surgical rehabilitation of hearing loss in osteogenesis imperfecta]

Osteogenesis imperfecta (OI) is a form of congenital osteoporosis. Depending on the type of OI, patients experience various types of hearing loss. Depending on the type and degree of hearing loss, various methods of hearing rehabilitation are used in this category of patients.

OBJECTIVE

To evaluate the features and results of surgical rehabilitation of hearing loss in patients with osteogenesis imperfecta.

MATERIAL AND METHODS

During the period from 2009 to 2022, 2221 primary stapedoplasty was performed in the department, of which 23 (1.04%) in 21 patients were performed in patients with OI. There were 14 women and 7 men. According to TPA, bilateral hearing loss was detected in 19 patients and unilateral in 2. Conductive hearing loss was observed in 9 cases and mixed - in 14. The average thresholds for bone conduction (BC) were 22.7±8.04 dB, and the bone-air interval (ABG) - 36.1±5.3 dB. According to CT of the temporal bones, all patients showed a bilateral and symmetrical decrease in the density of the auditory ossicles, and in 7 patients there were extensive areas of non-uniform decrease in the density of the bone labyrinth up to +500 - +1000 HU.21 patients underwent 23 operations: in 21 cases stapedoplasty with laser assistance and in 2 cases ossiculoplasty.

RESULTS

BC thresholds 6 months after surgery averaged 24.6±8.2 dB, and ABG - 12.1±2.9 dB. Closing of ABG ≤10 dB at spoken frequencies was detected in 30.5%, ABG ≤20 dB - in 95%. After 12 months or more after the operation, no change in the audiological parameters was noted.

CONCLUSIONS

Stapes surgery for conductive and mixed hearing loss in OI patients is functionally effective. The best results are achieved after therapy with bisphosphonates with preparations of sodium fluoride, calcium and vitamin D, performing the operation when the density of demineralization zones reaches 1000 HU and using laser assistance. Taking into account the demineralization of the bone structures of the temporal bone, it is recommended to use autocartilaginous stirrup prostheses to restore sound conduction or to cover the attachment area of other prostheses with autologous tissues to prevent necrosis of the long stalk of the incus and stabilize long-term functional results.

Treatments for hearing loss in osteogenesis imperfecta: a systematic review and meta-analysis on their efficacy

About 70% of people with osteogenesis imperfecta (OI) experience hearing loss. There is no cure for OI, and therapies to ameliorate hearing loss rely on conventional treatments for auditory impairments in the general population. The success rate of these treatments in the OI population with poor collagenous tissues is still unclear. Here, we conduct a systematic review and meta-analysis on the efficacy of treatments addressing hearing loss in OI. This study conforms to the reporting standards of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). Data sources include published articles in Medline via PubMed, Web of Science, Scopus, and Embase, from their inception to November 2020. Studies included individuals with OI undergoing a hearing loss treatment, having pre- and postoperative objective assessment of hearing function at a specified follow-up length. Our search identified 1144 articles, of which 67 were reviewed at full-text screening. A random-effects meta-analysis was conducted on the selected articles (n = 12) of people with OI that underwent stapes surgery. Success was assessed as the proportion of ears with a postoperative Air-Bone Gap (ABG) ≤ 10 dB. A systematic review was conducted on the remaining articles (n = 13) reporting on other treatments. No meta-analysis was conducted on the latter due to the low number of articles on the topic and the nature of single case studies. The meta-analysis shows that stapes surgeries have a low success rate of 59.08 (95% CI 45.87 to 71.66) in the OI population. The systematic review revealed that cochlear implants, bone-anchored hearing aids, and other implantable hearing aids proved to be feasible, although challenging, in the OI population, with only 2 unsuccessful cases among the 16 reviewed single cases. This analysis of published data on OI shows poor clinical outcomes for the procedures addressing hearing loss. Further studies on hearing loss treatments for OI people are needed. Notably, the mechanisms of hearing loss in OI need to be determined to develop successful and possibly non-invasive treatment strategies.

Stapedotomy using skeeter drill and self-retaining ear canal retractor: a single surgeon's 1000-plus surgical procedure experience

Objective

This study aimed to evaluate the long-term hearing outcomes in stapedotomy surgery using skeeter oto-drill and to assess safety in difficult situations.

Method

A retrospective study was conducted with 944 patients who underwent 1007 stapedotomy procedures over 16 years, performed by a single surgeon using a trans-canal approach and a self-retaining ear canal retractor. Hearing thresholds were calculated over four frequencies. Air–bone conduction hearing thresholds were obtained at 1, 5 and 10 years post-operatively and compared to the pre-operative records.

Results

Out of 1007 operated ears with one year follow up, 98.61 per cent of cases showed a negligible air–bone gap of equal to or less than 5 dB, 1.19 per cent of cases showed an air–bone gap equal to or more than 5 dB but less than 10 dB, and only 0.2 per cent of cases showed an air–bone gap of more than 10 dB.

Conclusion

In this study, using skeeter drill with a 0.6 mm diamond burr to make the fenestra was constant in all the cases and one of the safest techniques, showing persistent long-term hearing results.

Identification of a Rare Variant of c.1777G>A (p.G593S) in the COL1A1 Gene as the Etiology of Recurrent Osteogenesis Imperfecta by Whole-Exome Sequencing

BACKGROUND

Osteogenesis imperfecta (OI) is a rare heterogeneous disorder typically featured by fragile bones and susceptibility to fracture. The aim of the present study was to explore the genetic etiology of familial recurrent OI and the genotype-phenotype correlation.

METHODS

Karyotyping, chromosomal microarray analysis, and whole-exome sequencing (WES) were performed to determine the genetic etiology of OI in the enrolled family. Western blotting analysis was carried out using the fetal skin tissue for type I collagen production analysis.

RESULTS

At the first pregnancy, a c.1777G>A mutation in the COL1A1 gene was detected in the fetus who exhibited skeletal dysplasia. In this second pregnancy, severe fetal skeletal dysplasia was also presented without significant chromosomal abnormality detected by karyotype and chromosomal microarray analysis in the fetus. Further WES results demonstrated a de novo missense mutation of c.1777G>A (p.G593S) in the fetus, which was classified as a pathogenic variant according to the ACMG guidelines. The recurrent mutation in the two fetuses hinted at the possible existence of gonadal mosaicism in the parents, while no mutation in the COL1A1 gene was identified in the DNA from the father's sperm. In addition, Western blot results demonstrated no reduced type I procollagen production in the affected fetus compared with the age-matched controls.

CONCLUSIONS

To the best of our knowledge, this is the first study that identified a rare variant of c.1777G>A in the COL1A1 gene that led to recurrent OI in the Chinese population. Additionally, we believe that this rare variant of c.1777G>A in the COL1A1 gene will lead to OI type II. The results of the present study further verify the application value of WES in identifying fetuses with ultrasound anomalies.

Oral health-related quality of life in children with osteogenesis imperfecta

Purpose

Osteogenesis imperfecta (OI) results from mutations in the genes involved in the modification or biosynthesis of collagen. This study aimed to assess the oral health-related quality of life (OHRQoL) in children with OI.

Methodology

Participants were recruited from a highly specialised OI centre for children. The Child Oral-Health Impact Profile—Short Form (COHIP-SF) was used, adding demographic and qualitative questions. Children aged 8–16 years participated between January and October 2019. Statistical analysis was carried out. A higher COHIP-SF score indicates better OHRQoL (maximum score, 76).

Results

One hundred and six (106) children participated (44 female, mean age 11.93 years). COHIP-SF median score was 59. Children reporting mild OI (n = 55) had higher median scores (62) compared to severe OI (n = 7) with median scores of 55 (P = 0.087). When comparing mixed (< 12 years, n = 46) and permanent dentition (≥ 12, n = 60), no significant difference in OHRQoL was seen (P = 0.977). There was no significant difference between severities for each COHIP-SF domain. Limited data on the presence of dentinogenesis imperfecta did not impact overall score (P = 0.109), but was significant in the oral-health domain (P = 0.033).

Qualitative

Common themes were the need for braces, discolouration, pain and function.

Conclusion

This study confirmed that children with OI have dental concerns in areas including oral health, functional well-being and socio-emotional well-being. This was related to severity of OI.

New Structural and Single Nucleotide Mutations in Type I and Type II Collagens in Taiwanese Children With Type I and Type II Collagenopathies

Collagenopathy is a rare genetic condition characterized by abnormality in either collagen structure or metabolism. Variations in its clinical presentations highlight diversity in the genetic causes and potential existence of concurrent mutations. Through whole exome sequencing (WES) complemented with multiplex ligation-dependent probe amplification, we identified the genetic etiologies for six cases with osteogenesis imperfecta (OI) in COL1A1 (p.T1298N, p.Q1280Pfs^∗51, and p.G557Vfs^∗23) and COL1A2 (c.1-1677_133-441del) as well as three cases with spondyloepiphyseal dysplasia congenita in COL2A1 (p.G1041S, p.G654S, and p.G441A). Co-occurrence of COL1A1 and WNT1 mutations was found in a patient with a mild OI phenotype but severe osteoporosis. These findings extended the pathogenic variant spectrum of COL1A1, COL1A2, and COL2A1 for type I and type II collagenopathies. Although WES provides a fast and accurate method to identify the genetic causes in most of the patients with type I and type II collagenopathies, its limitation of detecting CNVs because of variable capturing uniformity should be kept in mind when interpreting the results. Taken together, we demonstrate that multiple genetic characterizing technologies can provide an accurate and efficient molecular diagnostic of new genetic variants in disease-causing genes that are compatible with clinical phenotypes.

Osteogenesis imperfecta in children

Osteogenesis imperfecta (OI) is a disease characterised by altered bone tissue material properties together with abnormal micro and macro-architecture and thus bone fragility, increased bone turnover and hyperosteocytosis. Increasingly appreciated are the soft tissue changes, sarcopenia in particular. Approaches to treatment are now multidisciplinary, with bisphosphonates having been the primary pharmacological intervention over the last 20 years. Whilst meta-analyses suggest that anti-fracture efficacy across the life course is equivocal, there is good evidence that for children bisphosphonates reduce fracture risk, increase vertebral size and improve vertebral shape, as well as improving motor function and mobility. The genetics of OI continues to provide insights into the molecular pathogenesis of the disease, although the pathophysiology is less clear. The complexity of the multi-scale interactions of bone tissue with cellular function are gradually being disentangled, but the fundamental question of why increased tissue brittleness should be associated with so many other changes is unclear; ER stress, pro-inflammatory cytokines, accelerated senesence and altered matrix component release might all contribute, but a unifying hypothesis remains elusive. New approaches to therapy are focussed on increasing bone mass, following the paradigm established by the treatment of postmenopausal osteoporosis. For adults, this brings the prospect of restoring previously lost bone - for children, particularly at the severe end of the spectrum, the possibility of further reducing fracture frequency and possibly altering growth and long term function are attractive. The alternatives that might affect tissue brittleness are autophagy enhancement (through the removal of abnormal type I collagen aggregates) and stem cell transplantation - both still at the preclinical stage of assessment. Preclinical assessment is not supportive of targeting inflammatory pathways, although understanding why TGFb signalling is increased, and whether that presents a treatment target in OI, remains to be established.

Increased cochlear otic capsule thickness and intracortical canal porosity in the oim mouse model of osteogenesis imperfecta

Osteogenesis imperfecta (OI or brittle bone disease) is a group of genetic disorders of the connective tissues caused mainly by mutations in the genes encoding collagen type I. Clinical manifestations of OI include skeletal fragility, bone deformities, and severe functional disabilities, such as hearing loss. Progressive hearing loss, usually beginning in childhood, affects approximately 70% of people with OI with more than half of the cases involving the inner ear. There is no cure for OI nor a treatment to ameliorate its corresponding hearing loss, and very little is known about the properties of OI ears. In this study, we investigate the morphology of the otic capsule and the cochlea in the inner ear of the oim mouse model of OI. High-resolution 3D images of 8-week old oim and WT inner ears were acquired using synchrotron microtomography. Volumetric morphometric measurements were conducted for the otic capsule, its intracortical canal network and osteocyte lacunae, and for the cochlear spiral ducts. Our results show that the morphology of the cochlea is preserved in the oim ears at 8 weeks of age but the otic capsule has a greater cortical thickness and altered intracortical bone porosity, with a larger number and volume density of highly branched canals in the oim otic capsule. These results portray a state of compromised bone quality in the otic capsule of the oim mice that may contribute to their hearing loss.

Stapes surgery in osteogenesis imperfecta: retrospective analysis of 18 operated ears

PURPOSE

To evaluate short and long term results of stapes surgery in patients with osteogenesis imperfecta (OI), METHODS: Retrospective case series of 18 primary stapes surgeries performed on 11 hearing-impaired OI patients with evidence of stapes fixation, in a Tertiary referral center. We analysed pre-operative and post-operative hearing results at 1 month and at least 1 year RESULTS: The main operative findings were stapes fixation, thickened footplate and fragile or fractured stapes crura. No revision surgery was necessary. Hearing improvement was achieved in 94% of the cases. We obtained an air-bone gap closure to within 10 dB in 46% of the cases and to within 15 dB in 92% of the cases at 1-year follow-up. The mean hearing gain in air conduction (at 0.5, 1, 2 and 4 kHz) was 18.4 dB at 1 month and 22.4 dB at 1 year.

CONCLUSION

Stapes surgery in OI gives good results with few complications in our series. A hearing gain is often obtained in spite of the sensorineural hearing loss caused by the natural progression of the disease.

The impact of stapes surgery on osteogenesis imperfecta: a retrospective comparison of operative outcomes with those for patients with otosclerosis

BACKGROUND

While stapes surgery has long been employed as a means of improving hearing in patients with otosclerosis, it remains controversial as to whether such surgical intervention is of value in patients with osteogenesis imperfecta (OI).

AIMS

This study was therefore designed to determine whether stapes surgery could still be reliably performed in OI patients as it is in otosclerosis patients.

MATERIALS AND METHODS

Seventeen OI patients and 18 matched otosclerosis patients were included. In both of these groups, 22 ears underwent primary stapes surgery. Audiometric follow-up data for patients in these two treatment groups were available for between 2 weeks and 25 years post-surgery.

RESULTS

We detected significant improvements in both the short- and long-term mean air conduction threshold and reduced air-bone gap (ABG) in both treatment groups as measured via postoperative follow-up audiometry. There was no difference between the OI and otosclerosis patient groups with respect to short- and long-term postoperative audiometric. Conclusions and significance: The majority of patients with both OI and otosclerosis that underwent stapes surgery achieved beneficial gains in hearing function. We did not observe any differences in short- or long-term post-operative hearing gains or ABG reductions between the two groups.

Novel Compound Heterozygous Mutations in CRTAP Cause Rare Autosomal Recessive Osteogenesis Imperfecta

Whole-exome sequencing (WES) has advantages over the traditional molecular test by screening 20,000 genes simultaneously and has become an invaluable tool for genetic diagnosis in clinical practice. Here, we reported a family with a child and a fetus presenting undiagnosed skeletal dysplasia phenotypes, while the parents were asymptomatic. WES was applied to the parents and affected fetus to identify the genetic cause of the phenotypes. We identified novel compound heterozygous mutations consisting of a single-nucleotide variant (SNV) and a large deletion in the CRTAP gene (NM_006371.4:c.1153-3C > G/hg19 chr3:g.32398837_34210906del). Genetic alterations of CRTAP are known to cause osteogenesis imperfecta (OI) in an autosomal recessive manner. Further examination of the proband’s elder sibling who was diagnosed as OI after birth found that she shares the inherited compound heterozygous mutations of CRTAP; thus, the findings support the disease-causing role of CRTAP mutations. Through the in vitro molecular test and in silico analysis, the deleterious effects of the splicing-altering SNV in CRTAP (c.1153-3C > G) on gene product were confirmed. Collectively, our WES-based pathogenic variant discovery pipeline identifies the SNVs and copy number variation to delineate the genetic cause on the proband affected with OI. The data not only extend the knowledge of mutation spectrum in patients with skeletal dysplasia but also demonstrate that WES holds great promise for genetic screening of rare diseases in clinical settings.

Oral Bisphosphonate Therapy for Osteogenesis Imperfecta: A Systematic Review and Meta-Analysis of Six Randomized Placebo-Controlled Trials

Objective

To assess the effectiveness and safety of oral bisphosphonates in increasing bone mineral density (BMD), reducing fractures, and improving clinical function in patients with osteogenesis imperfecta (OI).

Methods

Studies were eligible for inclusion if they were randomized controlled trials of directly comparing oral bisphosphonate therapy with placebo‐group in OI patients. Data synthesis regarding to bone mineral density as measured by dual‐energy X‐ray absorptiometry (DEXA), decreased fracture incidence, change in biochemical markers of bone and mineral metabolism, bone histology, growth, bone pain, quality of life, and others were assessed, and meta‐analysis done when possible.

Results

From 98 potential references and six randomized controlled studies a total of 263 participants receiving oral bisphosphonates and 143 placebo treatments contributed data to meta‐analysis. Pooled meta‐analysis of three studies suggested that there was significant difference between bisphosphonate treated group and placebo in number of patients with at least one fracture (mean difference 0.53, 95% confidence interval 0.32–0.89, P = 0.02). Pooled meta‐analysis of two studies suggested that significant difference was noted between bisphosphonate treated group and placebo in mean percentage change in spine BMD (T‐score) (mean difference 28.43, 95% confidence interval 7.09‐49.77, P = 0.009). The similar effect was shown in the term of mean change (Z‐score) in spine BMD.

Conclusions

Significant improvement in lumbar areal BMD in patients affected with OI has been shown when treated with oral bisphosphonates, even though only a small population was enrolled. We cannot draw a definite conclusion that the increase in BMD can be translated into fracture reduction and clinical functional improvement. The optimal method, dose, type, initiation, and duration of oral bisphosphonates therapy still remains unclear. Well‐designed, adequately‐powered, placebo‐controlled RCTs investigating the effects of oral bisphosphonates on fractures reduction and improvement in quality of life in both children and adults are studied here.

Reproductive options for families at risk of Osteogenesis Imperfecta: a review

Background

Osteogenesis Imperfecta (OI) is a rare genetic disorder involving bone fragility. OI patients typically suffer from numerous fractures, skeletal deformities, shortness of stature and hearing loss. The disorder is characterised by genetic and clinical heterogeneity. Pathogenic variants in more than 20 different genes can lead to OI, and phenotypes can range from mild to lethal forms. As a genetic disorder which undoubtedly affects quality of life, OI significantly alters the reproductive confidence of families at risk. The current review describes a selection of the latest reproductive approaches which may be suitable for prospective parents faced with a risk of OI. The aim of the review is to alleviate suffering in relation to family planning around OI, by enabling prospective parents to make informed and independent decisions.

Main body

The current review provides a comprehensive overview of possible reproductive options for people with OI and for unaffected carriers of OI pathogenic genetic variants. The review considers reproductive options across all phases of family planning, including pre-pregnancy, fertilisation, pregnancy, and post-pregnancy. Special attention is given to the more modern techniques of assisted reproduction, such as preconception carrier screening, preimplantation genetic testing for monogenic diseases and non-invasive prenatal testing. The review outlines the methodologies of the different reproductive approaches available to OI families and highlights their advantages and disadvantages. These are presented as a decision tree, which takes into account the autosomal dominant and autosomal recessive nature of the OI variants, and the OI-related risks of people without OI.

The complex process of decision-making around OI reproductive options is also discussed from an ethical perspective.

Conclusion

The rapid development of molecular techniques has led to the availability of a wide variety of reproductive options for prospective parents faced with a risk of OI. However, such options may raise ethical concerns in terms of methodologies, choice management and good clinical practice in reproductive care, which are yet to be fully addressed.

Hearing loss in individuals with osteogenesis imperfecta in North America: Results from a multicenter study

Hearing loss (HL) is an extra-skeletal manifestation of the connective tissue disorder osteogenesis imperfecta (OI). Systematic evaluation of the prevalence and characteristics of HL in COL1A1/COL1A2-related OI will contribute to a better clinical management of individuals with OI. We collected and analyzed pure-tone audiometry data from 312 individuals with OI who were enrolled in the Linked Clinical Research Centers and the Brittle Bone Disorders Consortium. The prevalence, type, and severity of HL in COL1A1/COL1A2-related OI are reported. We show that the prevalence of HL in OI is 28% and increased with age in Type I OI but not in Types III and IV. Individuals with OI Types III and IV are at a higher risk to develop HL in the first decade of life when compared to OI Type I. We also show that the prevalence of SNHL is higher in females with OI compared to males. This study reveals new insights regarding prevalence of HL in OI including a lower general prevalence of HL in COL1A1/COL1A2-related OI than previously reported (28.3 vs. 65%) and high prevalence of SNHL in females. Our data support the need in early routine hearing evaluation in all types of OI that can be adjusted to the severity of the skeletal disease.

Clinical manifestations of osteogenesis imperfecta in adulthood: An integrative review of quantitative studies and case reports

Osteogenesis imperfecta (OI) is a rare genetic disorder of the bones caused by a mutation in Type I collagen genes. As adults with OI are aging, medical concerns secondary to OI may arise. This integrative review sought to review, appraise, and synthesize the clinical manifestations faced by adults with OI. Four electronic bibliographic databases were searched. Published quantitative, qualitative, and mixed-methods studies, as well as case reports from 2000 to March 2019, addressing a clinical manifestation in adulthood, were reviewed. Eligible studies and case reports were subsequently appraised using the Mixed Methods Appraisal Tool and Case Report Checklist, respectively. Twenty quantitative studies and 88 case reports were included for review regardless of the varying methodological quality score. These studies collectively included 2,510 adults with different OI types. Several clinical manifestations were studied, and included: hearing loss, cardiac diseases, pregnancy complications, cerebrovascular manifestations, musculoskeletal manifestations, respiratory manifestations, vision impairment, and other clinical manifestations. Increased awareness may optimize prevention, treatment, and follow-up. Opportunities to enhance the methodological quality of research including better design and methodology, multisite collaborations, and larger and diverse sampling will optimize the generalizability and transferability of findings.

Results of stapedotomy in otosurgical treatment of adult patients with osteogenesis imperfecta

OBJECTIVE

This is a retrospective study of hearing results and characteristics of osteogenesis imperfecta (OI) patients treated for hearing loss by stapedotomy at tertiary reference center.

METHODS

This study enrolled 20 patients with a clinical diagnosis of OI- (11M:9F). 18 patients (90%) underwent surgery due to hearing loss in the period 2003-16. The audiometric analysis provides the pure tone audiometry results of stapedotomy in adult patients in 2 periods (≤12 months and >12 months). Air-bone gap (ABG), hearing gain (HG), and changes in air and bone conduction thresholds after surgical treatment were analyzed.

RESULTS

In short-time follow-up we noted statistically significant improvement in mean AC thresholds and ABG (p < 0.001 for both), change in mean BC thresholds was statistically negligible. Comparing the observation periods short-term and long-term, it was found that AC thresholds, ABG, HG, ABG closure did not significantly change, although BC thresholds and BC closure deteriorated significantly (p < 0.05).

CONCLUSION

Stapes surgery for OI can be considered as a method of treating the conductive and/or mixed hearing loss suffered by these patients; however, the surgery is more difficult than that for otosclerosis because OI cases often have extremely difficult anatomical conditions. The hearing results of OI stapes surgery differ from typical otosclerosis cases, with the ABG closure not being as good. In addition, sensorineural hearing loss inevitably progresses.

Incorporating the patient perspective in the study of rare bone disease: insights from the osteogenesis imperfecta community

There is limited research which examines health concerns of individuals with osteogenesis imperfecta (OI). Discussion groups with leaders of the adult OI community identified a broad range of medical priorities beyond fractures and brittle bones. Our work underscores the need to include patient-reported outcomes in rare bone disease research.

INTRODUCTION

Osteogenesis imperfecta (OI) is a rare genetic disorder affecting collagen protein leading to brittle bones and a number of other medical complications. To date, there is limited research which examines the life-long process of aging with this rare disease, much less the perspective of individuals with OI.

METHODS

In order to explore and prioritize health concerns that adults with OI feel have been inadequately addressed in health care and research, investigators held discussions with leaders from the global adult OI community. The meetings were held in August 2017 at the 13th International Conference on OI in Oslo, Norway as part of the preconference seminar "Patient Participation in OI Research". Investigators were part of the Brittle Bone Disease Consortium (BBDC), a multicenter research program devoted to the study of OI, and their focus was on patient-reported outcomes (PRO).

RESULTS

Participants noted that while fractures and brittle bones are the most common feature of OI, a number of body systems are under-studied in this disorder. They particularly emphasized breathing, hearing, and the effects of aging as primary concerns that researchers and physicians may not fully understand or address. Other areas included pain, gastrointestinal problems, mental health, nutrition, menopause/pregnancy, and basilar invagination. Participants also emphasized that they must be informed of study results. They underscored that outcome measures incorporated into future drug trials must look beyond fractures and consider the whole patient.

CONCLUSIONS

This work will help guide the incorporation of PROs into the next phase of the BBDC Natural History Study of OI and underscores the importance of including PROs in the study of rare diseases.

Osteogenesis imperfecta and the teeth, eyes, and ears-a study of non-skeletal phenotypes in adults

Osteogenesis imperfecta (OI) is a disease causing bone fragility; however, it potentially affects all organs with a high content of collagen, including ears, teeth, and eyes. The study is cross-sectional and compares non-skeletal characteristics in adults with OI that clinicians should be aware of when caring for patients with OI.

INTRODUCTION

Osteogenesis imperfecta (OI) is a hereditary connective tissue disorder. The skeletal fragility is pronounced; however, OI leads to a number of extra-skeletal symptoms related to the ubiquity of collagen type 1 throughout the human body. The vast majority of knowledge is derived from studies performed in the pediatric population. Thus, we aimed to investigate the nature and prevalence of ophthalmologic, odontologic, and otologic phenotypes in an adult population with OI.

METHODS

The study population comprises 85 Danish OI patients (age 44.9 ± 15.9 years). Fifty-eight patients had OI type I, 12 OI type III, and 15 OI type IV according to the classification by Sillence. Audiometric evaluations and dental examinations were performed in 62 and 73 patients, respectively. Ophthalmologic investigations were performed in 64 patients, including measurements of the central corneal thickness.

RESULTS

All patients, except two, had corneal thickness below the normal reference value. Patients with OI type I and patients with a quantitative collagen defect had thinner corneas compared to patients with OI type III and other patients with a qualitative collagen defect. One patient in this cohort was diagnosed with and treated for acute glaucoma. Dentinogenesis imperfecta was diagnosed in one fourth of the patients, based on clinical and radiographic findings. This condition was predominately seen in patients with moderate to severe OI. Hearing loss requiring treatment was found in 15 of 62 patients, of whom three were untreated. The most prevalent type of hearing loss (HL) was sensorineural hearing loss, whereas conductive HL was solely seen in patients with OI type III. The patients with the most severe degrees of HL were patients with mild forms of OI. Age was associated with increased HL.

CONCLUSION

Although significant health problems outside the skeleton are frequent in adult patients with OI, the patients are not consistently monitored and treated for their symptoms. Clinicians treating adult patients with OI should be aware of non-skeletal health issues and consider including regular interdisciplinary check-ups in the management plan for adult OI patients.

Longitudinal analysis of the audiological phenotype in osteogenesis imperfecta: a follow-up study

Objective

This prospective study involved a longitudinal analysis of the progression of hearing thresholds in patients with osteogenesis imperfecta.

Methods

Audiometric results from 36 osteogenesis imperfecta patients (age range, 6–79 years) were compared between two test times with an average interval of 4 years. Audiometric evaluation included acoustic admittance measurements, acoustic stapedial reflex measurements, pure tone audiometry and otoacoustic emissions testing.

Results

Air conduction pure tone average, corrected for sex and age, and bone conduction pure tone average increased significantly in the study population (p < 0.05 and p < 0.001, respectively). In 14.3 per cent of the evaluated ears, an alteration in type and/or severity of hearing loss was observed.

Conclusion

After an average time interval of four years, significant changes in hearing status occurred in a population of osteogenesis imperfecta patients. These findings highlight the importance of regular audiological follow up in osteogenesis imperfecta patients, including audiometry, and measurements of acoustic admittance, acoustic stapedial reflexes and otoacoustic emissions.

Safe Intraoperative Neurophysiologic Monitoring During Posterior Spinal Fusion in a Patient With Cochlear Implants

OBJECTIVE

Cochlear implants are generally considered a contraindication for any procedure requiring electrical stimulation near the implant. We present a case of a patient undergoing intraoperative transcranial electrical motor-evoked potential monitoring with a cochlear implant without adverse outcomes.

PATIENT

A 12-year-old girl with a history of VACTERL presented with worsening congenital kyphosis and bilateral severe-to-profound hearing loss. Since age 7 the patient used a cochlear implant in the right ear and hearing aid in the left ear. Physical examination and magnetic resonance imaging in 2016 revealed a left-sided 66-degree thoracolumbar kyphosis at T11 making the patient a candidate for surgical correction.

INTERVENTIONS

She underwent a posterior spinal fusion surgery, performed with intraoperative transcranial electrical motor-evoked potential monitoring. Steps were taken to mitigate electrical stimulation of the patient's cochlear implant.

MAIN OUTCOME MEASURES

Postoperative impedance of individual channels, audiometry, and neural response testing were compared with preoperative measurements.

RESULTS

Significant (>10%) impedance changes were observed postoperatively in channels 1, 2, 4, and 6; however, the net variation across all the channels was low (3%). The patient reported no hearing changes, and no significant changes in hearing threshold were seen in postoperative audiometric testing or neural response testing.

CONCLUSION

We present a case of successful posterior spinal fusion with intraoperative neurophysiological monitoring via transcranial electrical stimulation, in a patient with a cochlear implant. With proper precautions, motor-evoked potential monitoring can be safely performed in a patient with a cochlear implant.

Osteogenesis imperfecta - A clinical update

Osteogenesis imperfecta (OI) is the most common inherited form of bone fragility and includes a heterogenous group of genetic disorders which most commonly result from defects associated with type 1 collagen. 85%-90% of cases are inherited in an autosomal dominant manner and are caused by mutations in the COL1A1 and COL1A2 genes, leading to quantitative or qualitative defects in type 1 collagen. In the last decade, defects in several other proteins involved in the normal processing of type 1 collagen have been described. Recent advances in genetics have called for reconsideration of the classification of OI, however, most recent classifications align with the classic clinical classification by Sillence. The hallmark of the disease is bone fragility but other tissues are also affected. Intravenous bisphosphonates (BPs) are the most widely used intervention, having significant favorable effects regarding areal bone mineral density (BMD) and vertebral reshaping following fractures in growing children. BPs have a modest effect in long bone fracture incidence, their effects in adults with OI concerns only BMD, while there are reports of subtrochanteric fractures resembling atypical femoral fractures. Other therapies showing promising results include denosumab, teriparatide, sclerostin inhibition, combination therapy with antiresorptive and anabolic drugs and TGF-β inhibition. Gene targeting approaches are under evaluation. More research is needed to delineate the best therapeutic approach in this heterogeneous disease.

Novel mutation of FKBP10 in a pediatric patient with osteogenesis imperfecta type XI identified by clinical exome sequencing

Osteogenesis imperfecta (OI) is a hereditary disease characterized by bone fragility caused by mutations in the proteins that support the formation of the extracellular matrix in the bone. The diagnosis of OI begins with clinical suspicion, from phenotypic findings at birth, low-impact fractures during childhood or family history that may lead to it. However, the variability in the semiology of the disease does not allow establishing an early diagnosis in all cases, and unfortunately, specific clinical data provided by the literature only report 28 patients with OI type XI. This information is limited and heterogeneous, and therefore, detailed information on the natural history of this disease is not yet available. This paper reports the case of a male patient who, despite undergoing multidisciplinary management, did not have a diagnosis for a long period of time, and could only be given one with the use of whole-exome sequencing. The use of the next-generation sequencing in patients with ultrarare genetic diseases, including skeletal dysplasias, should be justified when clear clinical criteria and an improvement in the quality of life of the patients and their families are intended while reducing economic and time costs. Thus, this case report corresponds to the 29th patient affected with OI type XI, and the 18th mutation in FKBP10, causative of this pathology.

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.

Osteogenesis imperfecta

Skeletal deformity and bone fragility are the hallmarks of the brittle bone dysplasia osteogenesis imperfecta. The diagnosis of osteogenesis imperfecta usually depends on family history and clinical presentation characterized by a fracture (or fractures) during the prenatal period, at birth or in early childhood; genetic tests can confirm diagnosis. Osteogenesis imperfecta is caused by dominant autosomal mutations in the type I collagen coding genes (COL1A1 and COL1A2) in about 85% of individuals, affecting collagen quantity or structure. In the past decade, (mostly) recessive, dominant and X-linked defects in a wide variety of genes encoding proteins involved in type I collagen synthesis, processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells have been shown to cause osteogenesis imperfecta. The large number of causative genes has complicated the classic classification of the disease, and although a new genetic classification system is widely used, it is still debated. Phenotypic manifestations in many organs, in addition to bone, are reported, such as abnormalities in the cardiovascular and pulmonary systems, skin fragility, muscle weakness, hearing loss and dentinogenesis imperfecta. Management involves surgical and medical treatment of skeletal abnormalities, and treatment of other complications. More innovative approaches based on gene and cell therapy, and signalling pathway alterations, are under investigation.

Bisphosphonate therapy for osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta is caused by a genetic defect resulting in an abnormal type I collagen bone matrix which typically results in multiple fractures with little or no trauma. Bisphosphonates are used in an attempt to increase bone mineral density and reduce these fractures in people with osteogenesis imperfecta. This is an update of a previously published Cochrane Review.

OBJECTIVES

To assess the effectiveness and safety of bisphosphonates in increasing bone mineral density, reducing fractures and improving clinical function in people with osteogenesis imperfecta.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises references identified from comprehensive electronic database searches, handsearches of journals and conference proceedings. We additionally searched PubMed and major conference proceedings.Date of the most recent search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Register: 28 April 2016.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing bisphosphonates to placebo, no treatment, or comparator interventions in all types of osteogenesis imperfecta.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias of the included trials.

MAIN RESULTS

Fourteen trials (819 participants) were included. Overall, the trials were mainly at a low risk of bias, although selective reporting was an issue in several of the trials. Data for oral bisphosphonates versus placebo could not be aggregated; a statistically significant difference favouring oral bisphosphonates in fracture risk reduction and number of fractures was noted in two trials. No differences were reported in the remaining three trials which commented on fracture incidence. Five trials reported data for spine bone mineral density; all found statistically significant increased lumbar spine density z scores for at least one time point studied. For intravenous bisphosphonates versus placebo, aggregated data from two trials showed no statistically significant difference for the number of participants with at least one fracture, risk ratio 0.56 (95% confidence interval 0.30 to 1.06). In the remaining trial no statistically significant difference was noted in fracture incidence. For spine bone mineral density, no statistically significant difference was noted in the aggregated data from two trials, mean difference 9.96 (95% confidence interval -2.51 to 22.43). In the remaining trial a statistically significant difference in mean per cent change in spine bone mineral density z score favoured intravenous bisphosphonates at six and 12 months. Data describing growth, bone pain, and functional outcomes after oral or intravenous bisphosphonate therapy, or both, as compared to placebo were incomplete among all studies, but do not show consistent improvements in these outcomes. Two studies compared different doses of bisphosphonates. No differences were found between doses when bone mineral density, fractures, and height or length z score were assessed. One trial compared oral versus intravenous bisphosphonates and found no differences in primary outcomes. Two studies compared the intravenous bisphosphonates zoledronic acid and pamidronate. There were no significant differences in primary outcome. However, the studies were at odds as to the relative benefit of zoledronic acid over pamidronate for lumbosacral bone mineral density at 12 months.

AUTHORS' CONCLUSIONS

Bisphophonates are commonly prescribed to individuals with osteogenesis imperfecta. Current evidence, albeit limited, demonstrates oral or intravenous bisphosphonates increase bone mineral density in children and adults with this condition. These were not shown to be different in their ability to increase bone mineral density. It is unclear whether oral or intravenous bisphosphonate treatment consistently decreases fractures, though multiple studies report this independently and no studies report an increased fracture rate with treatment. The studies included here do not show bisphosphonates conclusively improve clinical status (reduce pain; improve growth and functional mobility) in people with osteogenesis imperfecta. Given their current widespread and expected continued use, the optimal method, duration of therapy and long-term safety of bisphosphonate therapy require further investigation. In addition, attention should be given to long-term fracture reduction and improvement in quality of life indicators.

Clinical characteristics and the identification of novel mutations of COL1A1 and COL1A2 in 61 Chinese patients with osteogenesis imperfecta

Osteogenesis imperfecta (OI) is an inherited connective tissue disorder characterized by brittle bone fractures. The aim of the present study was to investigate the pathogenic gene mutation spectrum and clinical manifestations of mutations in collagen type I, alpha 1 (COL1A1) and collagen type I, alpha 2 (COL1A2) genes in Chinese patients with OI. A total of 61 unrelated Chinese OI patients with COL1A1 and COL1A2 mutations were recruited. All the exons and the exon-intron boundaries of the COL1A1 and COL1A2 genes were amplified and directly sequenced and lumbar spine bone mineral density was measured by dual‑energy X‑ray absorptiometry. The mutations of the 61 probands included 33 missense mutations, 8 nonsense mutations, 7 splicing variants and 13 frameshift mutations in COL1A1 and COL1A2 genes. A total of 25 novel mutations were identified, including 18 in COL1A1 and 7 in COL1A2. The mutations p.Gly257Arg, p.Gly767Ser and p.Gly821Ser in COL1A1 and p.Gly337Ser in COL1A2 may be located at a mutation hotspot for human OI due to the high repetition rate in OI patients. Family history was positive for OI in 33 probands (54%). All probands had suffered fractures and the most common fracture site was the femur. A total of 49 probands presented with blue sclerae (80.3%), 20 probands suffered from dentinogenesis imperfecta (32.8%) and 1 patient had hearing loss (1.6%). These findings may improve understanding of the pathogenic gene mutation spectrum and the clinical manifestations of mutations of COL1A1 and COL1A2 genes in Chinese patients with OI.

Cochlear implantation in patients with osteogenesis imperfecta

OBJECTIVE: Hearing loss has been shown to occur in 42% to 58% of patients with osteogenesis imperfecta (OI), with deafness arising in 25% to 60% of the patients. Implantation in patients with OI is relatively rare, with only 4 prior single case reports published in the English-language literature. The goal of this study was to evaluate the feasibility and functional outcome of cochlear implantation in 2 patients with OI tarda type I with profound sensorineural hearing loss.

STUDY DESIGN: Case series.

SETTING:. The implantations were performed in a tertiary academic referral center (Johns Hopkins University).

RESULTS: Though promontory vascularity was encountered, full insertion of a normal cochlear implant array could be achieved in both cases. One-year postimplant scores demonstrated 20 to 40 dB hearing thresholds, Consonant-Nucleus-Consonant Test word scores of 54% and 70%, Consonant-Nucleus-Consonant Test phoneme scores of 75% and 83%, Hearing in Noise Test scores of 76% and 99%, and Central Institute of the Deaf Sentence Score sentence scores of 99% and 100%, for patients 1 and 2, respectively.

CONCLUSIONS: Cochlear implantation in patients with OI is not only technically possible but the results are similar to implant outcomes for patients with sensorineural hearing loss from a variety of other causes. EBM rating: C (Otolaryngol Head Neck Surg 2005;132:735-40.)

Genotype and phenotype analysis of Taiwanese patients with osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta (OI) is a congenital disorder characterized by increased bone fragility and low bone mass.

METHODS

The presence of COL1A1 or COL1A2 mutation was investigated by direct sequencing in 72 patients with OI type I, III, or IV (27 males and 45 females; age range 0.2-62 years) from 37 unrelated families. The clinical features of these patients were also recorded.

RESULTS

Thirty-seven COL1A1 and COL1A2 mutations were identified, including 28 COL1A1 mutations and 9 COL1A2 mutations. Fifteen (41%) were novel mutations, and twelve (32%) were familial mutations. A review of their medical records revealed that the 72 patients could be classified into OI type I (n = 42), III (n = 5), and IV (n = 25). Twenty-nine patients had helical mutations (caused by the substitution of a glycine within the Gly-X-Y triplet domain of the triple helix), and 42 had haploinsufficiency mutations (caused by frameshift, nonsense, and splice-site mutations). Compared with haploinsufficiency, the patients with helical mutations had more severely impaired skeletal phenotypes, including shorter height, lower bone mineral density, poorer walking ability, more frequent manifestations of dentinogenesis imperfecta and scoliosis (p < 0.05).

CONCLUSIONS

Genotype and phenotype databases are expected to promote better genetic counseling and medical care of patients with OI.

Successful bone-anchored hearing aid implantation in a patient with osteogenesis imperfecta

Objective:

To report a case of successful bone-anchored hearing aid implantation in an adult patient with type III osteogenesis imperfecta, which is commonly regarded as a contraindication to this procedure.

Case report:

A 45-year-old man with type III osteogenesis imperfecta presented with mixed hearing loss. There was a mild sensorineural component in both ears, with an air–bone gap between 45 and 50 dB HL. He was implanted with a bone-anchored hearing aid. The audiological outcome was good, with no complications and good implant stability (as measured by resonance frequency analysis).

Conclusion:

To our knowledge, this is the first recorded case of bone-anchored hearing aid implantation in a patient with osteogenesis imperfecta.

Treatment of osteogenesis imperfecta in adults

BACKGROUND

Osteogenesis imperfecta (OI) is a heterogeneous rare connective tissue disorder commonly caused by mutations in the collagen type I genes. Pharmacological treatment has been most extensively studied in children, and there are only few studies comprising adult OI patients.

OBJECTIVES

i) To review the literature on the current medical management of OI in children and adults, and thereby identify unmet medical needs and ii) to present an overview of possible future treatment options.

RESULTS

Individualization and optimization of OI treatment in adults remain a challenge, because available treatments do not target the underlying collagen defect, and available literature gives weak support for treatment decisions for adult patients.

CONCLUSIONS

Bisphosphonates are still the most widely used pharmacological treatment for adult OI, but the current evidence supporting this is sparse and investigations on indications for choice and duration of treatment are needed.

Bisphosphonate therapy for osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta is caused by a genetic defect resulting in an abnormal type I collagen bone matrix which typically results in multiple fractures with little or no trauma. Bisphosphonates are used in an attempt to increase bone mineral density and reduce these fractures in people with osteogenesis imperfecta.

OBJECTIVES

To assess the effectiveness and safety of bisphosphonates in increasing bone mineral density, reducing fractures and improving clinical function in people with osteogenesis imperfecta.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises references identified from comprehensive electronic database searches, handsearches of journals and conference proceedings. We additionally searched PubMed and major conference proceedings.Date of the most recent search: 07 April 2014.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing bisphosphonates to placebo, no treatment, or comparator interventions in all types of osteogenesis imperfecta.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias of the included trials.

MAIN RESULTS

Fourteen trials (819 participants) were included. Overall, the trials were mainly at a low risk of bias, although selective reporting was an issue in several of the trials. Data for oral bisphosphonates versus placebo could not be aggregated; a statistically significant difference favouring oral bisphosphonates in fracture risk reduction and number of fractures was noted in two trials. No differences were reported in the remaining three trials which commented on fracture incidence. Five trials reported data for spine bone mineral density; all found statistically significant increased lumbar spine density z scores for at least one time point studied. For intravenous bisphosphonates versus placebo, aggregated data from two trials showed no statistically significant difference for the number of participants with at least one fracture, risk ratio 0.56 (95% confidence interval 0.30 to 1.06). In the remaining trial no statistically significant difference was noted in fracture incidence. For spine bone mineral density, no statistically significant difference was noted in the aggregated data from two trials, mean difference 9.96 (95% confidence interval -2.51 to 22.43). In the remaining trial a statistically significant difference in mean per cent change in spine bone mineral density z score favoured intravenous bisphosphonates at six and 12 months. Data describing growth, bone pain, and functional outcomes after oral or intravenous bisphosphonate therapy, or both, as compared to placebo were incomplete among all studies, but do not show consistent improvements in these outcomes. Two studies compared different doses of bisphosphonates. No differences were found between doses when bone mineral density, fractures, and height or length z score were assessed. One study compared oral versus intravenous bisphosphonates and found no differences in primary outcomes. Two studies compared the intravenous bisphosphonates zoledronic acid and pamidronate. There were no significant differences in primary outcome. However, the studies were at odds as to the relative benefit of zoledronic acid over pamidronate for lumbosacral bone mineral density at 12 months.

AUTHORS' CONCLUSIONS

Bisphophonates are commonly prescribed to individuals with osteogenesis imperfecta. Current evidence, albeit limited, demonstrates oral or intravenous bisphosphonates increase bone mineral density in children and adults with this condition. These were not shown to be different in their ability to increase bone mineral density. It is unclear whether oral or intravenous bisphosphonate treatment consistently decreases fractures, though multiple studies report this independently and no studies report an increased fracture rate with treatment. The studies included here do not show bisphosphonates conclusively improve clinical status (reduce pain; improve growth and functional mobility) in people with osteogenesis imperfecta. Given their current widespread and expected continued use, the optimal method, duration of therapy and long-term safety of bisphosphonate therapy require further investigation. In addition, attention should be given to long-term fracture reduction and improvement in quality of life indicators.

A cross-sectional multicenter study of osteogenesis imperfecta in North America - results from the linked clinical research centers

Osteogenesis imperfecta (OI) is the most common skeletal dysplasia that predisposes to recurrent fractures and bone deformities. In spite of significant advances in understanding the genetic basis of OI, there have been no large-scale natural history studies. To better understand the natural history and improve the care of patients, a network of Linked Clinical Research Centers (LCRC) was established. Subjects with OI were enrolled in a longitudinal study, and in this report, we present cross-sectional data on the largest cohort of OI subjects (n = 544). OI type III subjects had higher prevalence of dentinogenesis imperfecta, severe scoliosis, and long bone deformities as compared to those with OI types I and IV. Whereas the mean lumbar spine area bone mineral density (LS aBMD) was low across all OI subtypes, those with more severe forms had lower bone mass. Molecular testing may help predict the subtype in type I collagen-related OI. Analysis of such well-collected and unbiased data in OI can not only help answering questions that are relevant to patient care but also foster hypothesis-driven research, especially in the context of 'phenotypic expansion' driven by next-generation sequencing.

Osteogenesis imperfecta: clinical diagnosis, nomenclature and severity assessment

Recently, the genetic heterogeneity in osteogenesis imperfecta (OI), proposed in 1979 by Sillence et al., has been confirmed with molecular genetic studies. At present, 17 genetic causes of OI and closely related disorders have been identified and it is expected that more will follow. Unlike most reviews that have been published in the last decade on the genetic causes and biochemical processes leading to OI, this review focuses on the clinical classification of OI and elaborates on the newly proposed OI classification from 2010, which returned to a descriptive and numerical grouping of five OI syndromic groups. The new OI nomenclature and the pre-and postnatal severity assessment introduced in this review, emphasize the importance of phenotyping in order to diagnose, classify, and assess severity of OI. This will provide patients and their families with insight into the probable course of the disorder and it will allow physicians to evaluate the effect of therapy. A careful clinical description in combination with knowledge of the specific molecular genetic cause is the starting point for development and assessment of therapy in patients with heritable disorders including OI. © 2014 The Authors. American Journal of Medical Genetics Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution–NonCommercial–NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

'Double trouble': diagnostic challenges in Duchenne muscular dystrophy in patients with an additional hereditary skeletal dysplasia

Duchenne muscular dystrophy (DMD) is caused by mutations in Dystrophin and affects 1 in 3600-6000 males. It is characterized by progressive weakness leading to loss of ambulation, respiratory insufficiency, cardiomyopathy, and scoliosis. We describe the unusual phenotype of 3 patients with skeletal dysplasias in whom an additional diagnosis of DMD was later established. Two unrelated boys presented with osteogenesis imperfecta due to point mutations in COL1A1 and were both subsequently found to have a 1 bp frameshift deletion in the Dystrophin gene at age 3 and age 15 years, respectively. The third patient had a diagnosis of pseudoachondroplasia caused by a mutation in the COMP gene and was found to have a deletion of exons 48-50 in Dystrophin at age 9. We discuss the atypical presentation caused by the concomitant presence of 2 conditions affecting the musculoskeletal system, emphasizing aspects that may confound the presentation of a well-characterized disease like DMD. Additional series of patients with DMD and a secondary inherited condition are necessary to establish the natural history in this "double trouble" population. The recognition and accurate diagnosis of patients with two independent genetic disease processes is essential for management, prognosis, genetic risk assessment, and discussion regarding potential therapeutic interventions.

Otopathology in Osteogenesis Imperfecta

BACKGROUND

Osteogenesis Imperfecta (OI) is a genetic disorder of connective tissue matrix. OI is caused by mutations that affect type I collagen. The hearing loss in OI is characterized by onset in early adulthood and can be conductive, sensorineural, or mixed.

OBJECTIVES

To describe the temporal bone histopathology in 9 individuals with OI.

MATERIALS AND METHODS

Four adult, 1 pediatric, and 4 infant specimens were identified. Temporal bones were removed at autopsy and studied using light microscopy.

RESULTS

All adults and 1 pediatric specimen showed otosclerotic lesions. The findings included examples of clinical, histologic, and cochlear otosclerosis. The temporal bones of infants showed delayed ossification of the endochondral layer of bone and of the ossicles. There were no infant specimens with otosclerotic lesions.

CONCLUSION

Hearing loss in OI may be the result of clinical or cochlear otosclerosis. Fracture or atrophy of the ossicles may also be present in OI. A third unidentified mechanism of hearing loss may lead to cochlear degeneration. The described findings of otosclerotic lesions have implications for the observed heterogeneity of hearing loss patterns and for the surgical management of hearing loss in OI.

Evaluating for suspected child abuse: conditions that predispose to bleeding

Child abuse might be suspected when children present with cutaneous bruising, intracranial hemorrhage, or other manifestations of bleeding. In these cases, it is necessary to consider medical conditions that predispose to easy bleeding/bruising. When evaluating for the possibility of bleeding disorders and other conditions that predispose to hemorrhage, the pediatrician must consider the child's presenting history, medical history, and physical examination findings before initiating a laboratory investigation. Many medical conditions can predispose to easy bleeding. Before ordering laboratory tests for a disease, it is useful to understand the biochemical basis and clinical presentation of the disorder, condition prevalence, and test characteristics. This technical report reviews the major medical conditions that predispose to bruising/bleeding and should be considered when evaluating for abusive injury.