Audiometric, surgical, and genetic findings in 15 ears of patients with osteogenesis imperfecta: Stapes Surgery in Osteogenesis Imperfecta

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.

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.

A novel mutation in COL1A1 causing osteogenesis imperfecta/hearing loss

OBJECTIVES

To screen the COL1A1 and COL1A2 gene mutation sites in a family with type I osteogenesis imperfecta (OI)/hearing loss and analyze the characteristics and recovery of hearing loss in patients with osteogenesis imperfecta.

METHODS

The basic clinical data of OI proband and her parents were collected, and the COL1A1 and COL1A2 genes were detected in peripheral blood by PCR amplification and generation Sanger sequencing. Literature of stapedial surgery in patients with osteogenesis imperfecta was collected.

RESULTS

The heterozygous mutation of the 26 exon c.1922_1923 ins C in the OI progenitor COL1A1 gene led to the amino acid frameshift mutation of p.Pro 601FS, which was not detected in the phenotypic parents. The homozygous of exon 28 c.1782>G in COL1A2 was detected in the proband and her parents, resulting in changes in the protein p.Pro 549Ala.

CONCLUSION

The clinical symptoms of the OI proband is caused by heterozygous mutation of the 26 exon c.1922_1923 ins C in COL1A1 gene. Stapedial surgery can provide short-term and long-term hearing benefits for OI patients with hearing loss.

LEVEL OF EVIDENCE

Level 4.

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.

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.

High Heterogeneity of Temporal Bone CT Aspects in Osteogenesis Imperfecta Is Not Linked to Hearing Loss

OBJECTIVES

To determine whether temporal bone computed tomography (CT) features are linked to the presence and type of hearing loss in osteogenesis imperfecta (OI) when considering hearing-impaired OI patients and normally hearing (NH) OI ones. A secondary objective was to assess whether other factors influence CT features in a large sample: age, type of mutation, or bone mineral density (BMD).

METHODS

A total of 41 adults with OI underwent CTs and pure-tone audiometry in 82 ears. Hearing thresholds were normal in 64 out of 82 ears, and most had not been operated on for stapedectomy or stapedotomy. Ossicle density, footplates, oval and round windows, retrofenestral peri- and endolabyrinths, and temporal pneumatization were analyzed twice by an experienced radiologist. CT features were compared to hearing, age, collagen mutations, and bone mineral density.

RESULTS

Unexpectedly a high prevalence of footplate, ossicle, and otic capsule anomalies was observed, even in NH ears. Footplate hypodensity or thickening was mostly found in ears without conductive hearing loss. There were significantly more retrofenestral anomalies or window obstruction in ears with a sensorineural hearing loss component than in ears without. Age was significantly higher in ears with middle layer hypodensity than in ears without. Patients with mutations were expected to have reduced collagen quantity and had significantly more footplate or retrofenestral anomalies than those with qualitative mutations. BMD was significantly higher in ears without temporal hyperpneumatization.

CONCLUSION

Temporal bone CT features in OI are present in a large proportion of patients, had they hearing loss or not, and might be determined more by collagen mutation type than by age or BMD.

Osteogenesis Imperfecta: Search for Mutations in Patients from the Republic of Bashkortostan (Russia)

Osteogenesis imperfecta (OI) is an inherited disease of bone characterized by increased bone fragility. Here, we report the results of the molecular architecture of osteogenesis imperfecta research in patients from Bashkortostan Republic, Russia. In total, 16 mutations in COL1A1, 11 mutations in COL1A2, and 1 mutation in P3H1 and IFIMT5 genes were found in isolated states; 11 of them were not previously reported in literature. We found mutations in CLCN7, ALOX12B, PLEKHM1, ERCC4, ARSB, PTH1R, and TGFB1 that were not associated with OI pathogenesis in patients with increased bone fragility. Additionally, we found combined mutations (c.2869C>T, p. Gln957* in COL1A1 and c.1197+5G>A in COL1A2; c.579delT, p. Gly194fs in COL1A1 and c.1197+5G>A in COL1A2; c.2971G>C, p. Gly991Arg in COL1A2 and c.212G>C, p.Ser71Thr in FGF23; c.-14C>T in IFITM5 and c.1903C>T, p. Arg635* in LAMB3) in 4 patients with typical OI clinic phenotypes.

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.

[The experience in surgical treatment of hearing loss in Van der Hoeve patients]

Despite the rare incidence of Van der Hoeve syndrome in the population, the problem of treating patients with this type of disease is important for modern science and practical medicine. One of the most difficult tasks in treatment is to improve the quality of hearing. The world scientific community lacks a unified coordinated approach to the methods of auditory rehabilitation of patients with Van der Hoeve syndrome. In recent years, there have been tendencies in the scientific literature to increase the frequency of non-surgical approach due to the low incidence of satisfactory results of surgical treatment. In this regard, we present our experience of complex treatment of patients with Van der Hove syndrome, based on the use of modern surgical technologies and conservative pathogenetically substantiated treatment.

The Anesthetic Management of a Parturient With Osteogenesis Imperfecta Type I Undergoing Cesarean Delivery

Osteogenesis imperfecta (OI) is a rare disorder of bone fragility caused by mutations in the COL1A1/2 genes, which encode type I procollagen. It commonly manifests with bone fractures, joint dislocations, and easy bruising. OI patients presenting for surgery may pose multiple challenges to the anesthesiologist such as management of a potentially difficult airway and heightened positional fracture risks. We present a case detailing the spinal anesthetic management of a 28-year-old woman with type I OI requiring cesarean delivery for a 32-week intrauterine pregnancy with fetal cardiac anomalies.

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.

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.

Osteogenesis Imperfecta: Phenotypic and Intraoperative Findings Observed in Patients Treated Surgically at the World Hearing Centre

OBJECTIVES

Osteogenesis imperfecta (OI) is a systemic connective tissue disease that affects many systems and organs. Features of the disease are bone deformities, blue sclerae, and changes in the teeth, all of which may be accompanied by hearing loss. Bone fragility also affects structures of the ear, with half the patients developing changes in the auditory ossicles, which manifest as hearing loss. The most typical malformation affects the stapes, although the site of malformation within the middle ear varies. This study aims to characterize patients with OI who underwent surgery due to hearing loss and to find factors that affect the hearing results.

MATERIALS AND METHODS

This study presents an analysis of phenotypic and intraoperative changes among 20 patients with OI, treated surgically for hearing loss.

RESULTS

Hearing loss typically affects type I patients with OI. The most common changes concern stapes footplate, arms, and tympanic cavity lining. During reoperations, osseous regrowth was typically detected.

CONCLUSION

The greater the changes induced systemically by OI, the greater the risk of significant malformations in the middle ear. Patients with OI are at an increased risk of needing revision surgery and of suffering intraoperative complications such as bleeding, which hinders safe completion of the procedure.

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.

Temporal Bone Imaging Features in Osteogenesis Imperfecta

We present the case of a 33-year old woman with osteogenesis imperfecta (OI) with progressive hearing loss and persisting vertigo. On CT-scan, symmetric extensive lucency in the pericochlear bony otic capsule and promontorium was demonstrated. The MRI-scan demonstrated symmetric areas of increased signal intensity on the T2-images with moderate contrast enhancement in the same regions. These findings correlate histologically by undermineralized thickened bone, the hallmark of OI. Hearing loss is an important clinical feature in patients with OI. The value of temporal bone imaging lies in additional confirmation of the diagnosis, determining the extent disease and excluding concomitant pathology.

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.

Type I procollagen C-propeptide defects: study of genotype-phenotype correlation and predictive role of crystal structure

The type I procollagen carboxyterminal(C-)propeptides are crucial in directing correct assembly of the procollagen heterotrimers. Defects in these domains have anecdotally been reported in patients with Osteogenesis Imperfecta (OI) and few genotype-phenotype correlations have been described. To gain insight in the functional consequences of C-propeptide defects, we performed a systematic review of clinical, molecular, and biochemical findings in all patients in whom we identified a type I procollagen C-propeptide defect, and compared this with literature data. We report 30 unique type I procollagen C-propeptide variants, 24 of which are novel. The outcome of COL1A1 nonsense and frameshift variants depends on the location of the premature termination codon. Those located prior to 50-55 nucleotides upstream of the most 3' exon-exon junction lead to nonsense-mediated mRNA decay (NMD) and cause mild OI. Those located beyond this boundary escape NMD, generally lead to production of stable, overmodified procollagen chains, which may partly be retained intracellularly, and are usually associated with severe-to-lethal OI. Proα1(I)-C-propeptide defects that permit chain association result in more severe phenotypes than those inhibiting chain association. We demonstrate that the crystal structure of the proα1(III)-C-propeptide is a reliable tool to predict phenotypic severity for most COL1A1-C-propeptide missense variants, whereas for COL1A2-C-propeptide variants, the phenotypic outcome is milder than predicted.

Identification of a novel COL1A1 frameshift mutation, c.700delG, in a Chinese osteogenesis imperfecta family

Osteogenesis imperfecta (OI) is a family of genetic disorders associated with bone loss and fragility. Mutations associated with OI have been found in genes encoding the type I collagen chains. People with OI type I often produce insufficient α1-chain type I collagen because of frameshift, nonsense, or splice site mutations in COL1A1 or COL1A2. This report is of a Chinese daughter and mother who had both experienced two bone fractures. Because skeletal fragility is predominantly inherited, we focused on identifying mutations in COL1A1 and COL1A2 genes. A novel mutation in COL1A1, c.700delG, was detected by genomic DNA sequencing in the mother and daughter, but not in their relatives. The identification of this mutation led to the conclusion that they were affected by mild OI type I. Open reading frame analysis indicated that this frameshift mutation would truncate α1-chain type I collagen at residue p263 (p.E234KfsX264), while the wild-type protein would contain 1,464 residues. The clinical data were consistent with the patients’ diagnosis of mild OI type I caused by haploinsufficiency of α1-chain type I collagen. Combined with previous reports, identification of the novel mutation COL1A1-c.700delG in these patients suggests that additional genetic and environmental factors may influence the severity of OI.

Identification of a novel heterozygous mutation in exon 50 of the COL1A1 gene causing osteogenesis imperfecta

A 19-year-old woman was diagnosed with osteogenesis imperfecta (OI). She had sustained numerous low-trauma fractures throughout her childhood, including a recent pelvic fracture (superior and inferior ramus) following a low-impact fall. She had the classical blue sclerae, and dual energy X-ray absorptiometry (DEXA) bone scanning confirmed low bone mass for her age in the lumbar spine (Z-score was −2.6). However, despite these classical clinical features, the diagnosis of OI had not been entertained throughout the whole of her childhood. Sequencing of her genomic DNA revealed that she was heterozygous for the c.3880_3883dup mutation in exon 50 of the COL1A1 gene. This mutation is predicted to result in a frameshift at p.Thr1295, and truncating stop codon 3 amino acids downstream. To our knowledge, this mutation has not previously been reported in OI.

Otolaryngologic manifestations of skeletal dysplasias in children

This article reviews some of the otolaryngologic manifestations of skeletal dysplasias. Achondroplasia is discussed most comprehensively. Skeletal dysplasias are bone and cartilage disorders that disrupt the development of the long bones, craniofacial skeleton, and vertebral column, with the most notable characteristic being short stature. Children with skeletal dysplasias have various medical problems. These children often develop head and neck manifestations of their disorders. Hearing loss, middle ear disease, and respiratory difficulties are seen in these children. Otolaryngologists must be knowledgeable about these disorders to diagnose, treat, and appropriately refer children with skeletal dysplasias.

Hearing loss in osteogenesis imperfecta: characteristics and treatment considerations

Osteogenesis imperfecta (OI) is the most common heritable disorder of connective tissue. It is associated with fractures following relatively minor injury, blue sclerae, dentinogenesis imperfecta, increased joint mobility, short stature, and hearing loss. Structures in the otic capsule and inner ear share in the histologic features common to other skeletal tissues. OI is due to mutations involving several genes, the most commonly involved are the COL1A1 or COL1A2 genes which are responsible for the synthesis of the proalpha-1 and proalpha-2 polypeptide chains that form the type I collagen triple helix. A genotype/phenotype relationship to hearing loss has not been established in OI. Hearing loss is commonly found in OI with prevalence rates ranging from 50 to 92% in some studies. Hearing loss in OI may be conductive, mixed, or sensorineural and is more common by the second or third decade. Treatment options such as hearing aids, stapes surgery, and cochlear implants are discussed.