Osteogenesis imperfecta: clinical diagnosis, nomenclature and severity assessment

Phenotypic and genetic characteristics of a Dutch cohort of patients with X-linked osteoporosis due to PLS3 genetic variants

X-linked osteoporosis, caused by plastin 3 (PLS3) genetic variants, is a rare disease, characterized by low BMD and early-onset fractures, primarily affecting men. Our aim was to further elucidate the phenotypic characteristics, including sex-differences and genotype-phenotype analysis, in individuals with PLS3 variants. Our cohort comprises of 28 patients from 11 families, 18 men and 10 women, with a different PLS3 variant in each family. Demographic, clinical, and genetic features, imaging and laboratory tests, and treatment details were retrospectively reviewed. Men, (median age 47.0 y), demonstrated low Z-scores of the lumbar spine (-2.8 ± 1.7) and femoral neck (-1.7, IQR: -2.9-0.8). Most women (median age 49.5 y) had normal BMD, two had osteoporosis and one osteopenia. Moreover, men experienced a higher total number of fractures than women (men: 12.0, IQR: 6.7, 18.5, women: 2.0, IQR: 0.7, 5.2). Within one large family (n = 10) there was considerable heterogeneity regarding BMD and fractures, which might be explained by differences in factors like physical exercise (PE) or in (poly) genetic background. Extra-skeletal characteristics such as (mild) blue discoloration of the sclerae (men: 33.3%, women: 30.0%), joint hypermobility (44.4%, 70.0%) and skin hyperlaxity (50.0%, 20.0%) were observed. No relation was found between types and locations of variants and various clinical endpoints in men, using data from our cohort and the literature. Regarding treatment, all men and 40% of women received bone-active therapy, mostly oral bisphosphonates. Adult men demonstrated a 16.6% mean increase in the BMD of the lumbar spine (p = .03), after a median treatment duration of 6 y. In summary, this is so far the largest study of patients with X-linked osteoporosis, including an extensive genotype-phenotype analysis. A potential protective role of increasing weight-bearing PE in osteoporosis severity, as well as effects of penetrance, genetic background, or other environmental or lifestyle factors, need further study.

Lower limb deformity and gait deviations of osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta is a rare genetic disorder characterized by complex lower limb deformities, resulting in various gait limitations. This study aimed to (1) investigate the incidence and association between radiographic changes and gait impairment; (2) propose a lower limb deformity index to quantify deformity severity as well as gait performance.

METHODS

Bilateral X-ray images and 3D gait analysis results were assessed retrospectively from 48 patients with osteogenesis imperfecta. Multivariate linear regression was used to investigate the contribution of each deformity to gait performance. Eight scoring approaches of the proposed index, calculated from radiographic changes, were evaluated by their linear relationship to gait deviation.

RESULTS

Patients with osteogenesis imperfecta had high incidence of anterolateral bowing of femur, and anteromedial bowing of tibia, along with abducted hip, varus knee, hip flexion and ankle dorsiflexion deformities. Their maximum joint kinematics and kinetics were less than healthy controls, which was consistent with their major deformities. However, multivariate linear regression indicated a limited contribution from each deformity to gait deviation (only mechanical axis deviation out of 14 radiographic measures showed significance). Remarkably, our proposed index presented a significant linear correlation to gait deviation (Correlation coefficient: -0.650; R square: 0.423; F value: 33.719, p < 0.001).

CONCLUSIONS

This study preliminary demonstrated the association between lower limb deformities and gait deviations of patients with osteogenesis imperfecta and proposed a lower limb deformity index to quantify the deformity severity that reflects gait performance.

Registry-Based Frequency of Molecularly Confirmed Osteogenesis Imperfecta in a Swiss Cohort of Individuals With Connective Tissue Disorders

Patient registries play a crucial role in advancing our understanding of rare diseases, enabling the collection of comprehensive clinical and molecular data that inform diagnosis, treatment, and management strategies and advance our understanding of rare diseases. We showcase the first Swiss registry of 796 patients with suspected or confirmed connective tissue disorders (CTD) who were referred to our center over a period of 26 years between 1995 and 2022. The registry contains information on the natural history, anthropometrics, biochemical, histological, and genetic analyses. 61.3% of patients were referred by other hospitals or genetic specialists, with the primary reasons for referral being suspicion of Ehlers-Danlos syndrome (EDS) (53.6%) and osteogenesis imperfecta (OI) (28.1%). Molecular confirmation of these diagnoses was obtained in 60 cases of EDS and 98 cases of OI through genetic testing. In-depth analyses of 173 OI patients revealed that the majority of OI cases were caused by mutations in COL1A1 or COL1A2. Rarer variants were identified in genes involved in collagen synthesis and bone regulation. Genotype-phenotype correlations were observed in a small subset of patients, with a high prevalence of glycine substitutions in COL1A1 and COL1A2 variants associated with severe phenotypes. This registry offers insights into the molecular underpinnings of EDS and OI and underscores the importance of genetic testing for accurate diagnosis and management.

Six at Sixty. Commentary on osteogenesis imperfecta 1975-2025

Between 1975 and 1977, my collaborators and I conducted a whole-of-population study in Victoria, Australia, examining the various presentations and clinical manifestations of osteogenesis imperfecta (OI) and familial forms of bone fragility. In 1975, the prevailing view was that all presentations of OI reflected variable expression of pathogenic genomic variants at a single gene locus-possibly involving the recently identified protein, type I collagen. We concluded that OI was in fact genetically heterogeneous, setting the scene for future biochemical and genomic discoveries. Currently, OI is recognised to result from pathological variants in >20 genes, with variants in many further loci resulting in related forms of familial osteoporosis or special syndromes characterised by bone fragility. A dyadic nosology has been adopted to help clinicians, researchers and affected individuals in accessing OI diagnosis, treatment and research with a focus on precision medicine.

Perceived oral care needs and concerns of individuals with osteogenesis imperfecta

Introduction Osteogenesis imperfecta (OI) is a genetic condition most commonly caused by pathogenic variants in the genes encoding type I collagen which is the major protein of bone. Bone fractures are an important feature but it is also associated with dentinogenesis imperfecta (DI) and other dental anomalies.Aim To investigate the experiences of people living with OI related to their oral care. Method An anonymous survey developed for the Brittle Bone Society (BBS) was distributed in the United Kingdom and Ireland and was available online for three months to all members of the BBS via their website and social media platforms. Both parental reports of children with OI and adults living with OI were invited to participate.Results Of the 110 respondents, 69% identified as female (n = 76), 28% (n = 31) male, and 3% (n= 3) non-binary. The average age group was 26-45 years-old (42%; n = 46); with 21% (n = 23) below 16-years-old. In total, 45% self-reported mild OI (n = 49), 30% (n= 33) moderate, 21% (23) severe and 5% (n = 5) were unsure. Additionally, 44% (n = 48) self-reported DI, while 70% (n = 77) experienced dental problems related to OI. Concerns included appearance and bite issues. Access challenges were linked to OI severity.Conclusion Dentists need to be more aware of the effects of both DI and bisphosphonates in relation to treatment to improve care to individuals with OI, and more research is needed in this area.

A Deep Intronic Splice Variant in COL1A1 Causing Osteogenesis Imperfecta Type II

Osteogenesis imperfecta (OI) is a rare disease, hallmarked by bone fragility, multiple fractures, and deformities, and is commonly caused by pathogenic variants in the genes encoding type I collagen. Type II OI is the most severe form and is lethal in the perinatal period. Here, we report recurrence of perinatal lethal OI in two fetuses due to parental mosaicism for a deep intronic pathogenic variant at c.2451 + 77C > T in intron 35 of COL1A1, which resulted in aberrant splicing and the in-frame addition of 75 nucleotides into the mRNA. These patients highlight the importance of considering deep intronic variants in type 1 collagen genes in patients with high suspicion of OI, which may be missed with conventional genetic analysis.

A novel sliding double flexible intramedullary nail technique for the management of lower extremity long bone fractures and deformities in osteogenesis imperfecta

This study aimed to investigate the effectiveness of the sliding double flexible intramedullary nail technique (SDFIN) in managing lower extremity long bone fractures and deformities in patients with osteogenesis imperfecta (OI) based on radiographic measurements. This study was conducted involving type III or IV Silence OI patients who underwent treatment with SDFIN for fractures, deformity correction, or previous device failure. The surgical technique involved the insertion of two straight flexible intramedullary nails in each bone segment, with one inserted from the caudal epiphysis and the other from the proximal region. Clinical and radiological outcomes were evaluated with a mean follow-up of 62.8 ± 20.3 months. Among the 33 lower extremity long bone segments treated with SDFIN, revision was required in 12 segments, resulting in an overall complication rate of 51.5%. Complications included nail migrations observed in 10 cases, decreased joint range of motion in seven, refractures and malrotations in five, nail fracture, and nail extrusion in one case were observed. The femur group had a complication rate of 50%, while the tibia group had a rate of 53.3%. The SDFIN technique demonstrated satisfactory outcomes in managing leg fractures and deformities in OI patients. The technique showed comparable results to newly designed Faisser-Duval rods at a lower cost. Further research and refinement of the technique are necessary to reduce complications and improve patient outcomes.

Further Evidence of Early-Onset Osteoporosis and Bone Fractures as a New FGFR2-Related Phenotype

Primary osteoporosis in children and young adults often suggests a monogenic disease affecting bone microarchitecture and bone mineral density. While Osteogenesis Imperfecta (OI) is the most recognized genetic cause of recurrent fractures, many other genes involved in bone metabolism may contribute to osteoporosis. Among them, FGFR2 plays a critical role in bone growth and development by regulating osteoblast differentiation and proliferation, as well as chondrogenesis. Germline pathogenic FGFR2 variants are typically associated with syndromic craniosynostosis, conditions not characterized by bone fragility or osteoporosis. A report recently identified FGFR2 as a potential cause of dominant early-onset osteoporosis and bone fractures in a family. We report the case of a child affected by severe osteoporosis with multiple fractures. We performed clinical exome sequencing in trio to investigate potential genetic causes of the observed phenotype and identified a likely mosaic pathogenic FGFR2 variant, absent in both parental samples. Our findings provide further evidence that FGFR2 pathogenic variants can lead to a novel non-syndromic bone mineralization disorder, reinforcing the role of FGFR2 in the pathogenesis of early-onset osteoporosis.

Retrograde femoral nailing for deformity correction and fracture treatment in osteogenesis imperfecta: clinical and radiological assessment of a novel technique

INTRODUCTION

Intramedullary anterograde femoral nailing is a standard treatment for femoral deformity and fracture in osteogenesis imperfecta (OI). This study evaluates the clinical and radiological outcomes of a novel retrograde femoral nailing technique.

METHODS

A retrospective analysis was performed on 31 patients with OI who underwent retrograde femoral nailing using Dubow-Bailey nails from 2004 to 2019. A total of 54 femurs were treated for femoral deformity or fracture by three senior surgeons, with a mean follow-up of 2.7 years. Clinical outcomes, including knee range of motion and pain, were assessed. Radiological outcomes included deformity angle (DA), neck shaft angle (NSA), mechanical lateral distal femoral angle (mLDFA), and nail positioning on AP and lateral X-rays. Potential complications, including hip osteonecrosis, distal femoral growth arrest, and infections, were also evaluated.

RESULTS

The procedure showed favorable outcomes, with no postoperative knee motion limitations or persistent pain. The mean pre-operative DA on AP and lateral views was 29° and 40°, respectively, with no residual deformity after surgery. The mean NSA and mLDFA were 132° and 101° before surgery, compared to 143° and 89° post-operatively. Nail alignment was optimal in 81% of the femurs, with proper positioning in both the distal epiphysis and femoral neck. No cases of hip osteonecrosis, distal femoral growth arrest, or infection were reported. Hardware migration occurred in seven cases.

CONCLUSION

Retrograde femoral nailing is a safe and effective technique for managing femoral deformities and fractures in OI.

Hearing loss in Chinese osteogenesis imperfecta patients

PROPOSE

Osteogenesis imperfecta (OI) is a genetic connective tissue disorder primarily characterized by bone fragility. Hearing loss is an extra-skeletal manifestation of OI. This study aims to characterize the audiological findings of a sample of patients with OI in China.

METHODS

A total of 76 patients (aged 4-77 years) were recruited and evaluated using audiometric evaluations, including pure tone audiometry (PTA), acoustic admittance measurements, and distortion-product otoacoustic emissions (DPOAEs). Patients were categorized into 2 age groups: adults (more than 18 years) and children (under 18 years), and classified by hearing type: normal hearing, conductive, sensorineural, or mixed hearing loss.

RESULTS

Tympanometry (152 ears) showed 71.7% Type A tympanograms. There was a significant association between tympanogram type and hearing loss (p < 0.01). DPOAEs were predominantly abnormal in ears with sensorineural and mixed hearing loss (p < 0.01). PTA (146 ears) revealed hearing loss in 39.0%: 16.4% conductive, 15.1% sensorineural, and 7.5% mixed. Age correlated significantly with hearing loss type (p < 0.01). Adults' group exhibited higher pure-tone averages (11.3 dB vs. 8.8 dB, p < 0.01), average air-bone gap (2.5 dB vs.2.5 dB, p < 0.05), and bone conduction thresholds than children's group.

CONCLUSIONS

Hearing loss is common and progressive in Chinese OI patients, with a significant age-related increase in both the prevalence and severity of hearing loss. Establishing a hearing baseline and regular follow-up is essential for early intervention.

Evaluation of the benefits of adapted physical activity in children and adolescents with osteogenesis imperfecta: the MOVE-OI trial

BACKGROUND

Osteogenesis Imperfecta (OI) is a rare genetic disorder characterized by bone fragility and susceptibility to fractures. No curative treatment currently exists, and limited data are available on the effects of adapted physical activity (APA). This study evaluates the impact of APA on bone health, physical function, respiratory function, and quality of life in pediatric children with OI.

METHODS

The MOVE-OI trial (NCT04119388) is a prospective single-center study assessing the impact of a 12-month individualized APA program. Inclusion criteria included confirmed OI pathogenic variant, ages 6-18 years. Baseline (M0) and end-point (M12) assessments included clinical, radiological, and respiratory evaluations. The primary outcome was an improvement in the 6-min walk test (6MWT) distance. A non-parametric paired-test was performed for analysis.

RESULTS

Thirty participants (16 males, median age 10.5 years) completed the program. A 17% increase in the 6MWT distance (p = 0.0007) was observed, with an average improvement of 98 m. No significant bone density or respiratory function changes were detected. Fracture incidence decreased (from 40 to 20%), and quality-of-life improvements were noted in participants with high baseline difficulty scores.

CONCLUSION

APA improves endurance and physical capacity in children with OI. Multidisciplinary care and further research are needed to enhance long-term outcomes.

Mineralised bone properties in a child with recessive osteogenesis imperfecta type XIV and in a conditional Tmem38b knockout murine model (Runx2-Cre; Tmem38bfl/fl)

INTRODUCTION

OI type XIV is caused by variants in the TMEM38B gene, encoding for the ubiquitously expressed endoplasmic reticulum trimeric intracellular cation channel type B (TRIC-B), causing disruptions in calcium homeostasis and collagen synthesis. Patients with OI type XIV present with a highly variable clinical phenotype, ranging from asymptomatic to severe. We present here data from a 6 year clinical follow-up of two affected siblings and bone tissue characterisation obtained during corrective surgery from one of the patients, as well as tibiae from a novel Tmem38b conditional knockout murine model (Runx2-Cre; Tmem38bfl/fl).

METHODS

Clinical examinations of the patients include bone mineral density (BMD) measurements using dual-energy x-ray absorptiometry (DXA) scanning and gait analyses. Quantitative backscattered electron imaging (qBEI) was used to investigate bone mineralisation density distribution (BMDD) and osteocyte lacunae properties, and confocal laser scanning microscopy was used to quantify the osteocyte lacuno-canalicular network (OLCN) in both human and murine specimens.

RESULTS

Both patients (P1, P2) presented with muscular hypotension, fatigue, progression of lower limb deformities, and fractures. BMDD of the osteonal bone region of the tibia and fibula specimens obtained from P1 revealed no significant shift towards higher mineral content as seen in "classical" OI. Osteocyte lacunae porosity was elevated and analyses of the OLCN revealed a reduction in canalicular density and lacunar degree. Runx2-Cre; Tmem38bfl/fl mice exhibited a very severe skeletal phenotype, with 10/12 of the tibiae showing evidence of fractures, bone deformations, or calluses. In contrast to the patient samples, both the cortex and metaphysis of mutant mice demonstrated a significant increase in the average mineral content (CaMean) and the peak of the distribution (CaPeak), as well as in osteocyte lacunae porosity (P < 0.0001), whereas canalicular density (P < 0.0001), and lacunar degree (P = 0.0004) were decreased.

CONCLUSION

While Runx2-Cre; Tmem38bfl/fl mice exhibit hypermineralisation of the bone matrix, this is not apparent in bone specimens obtained from the OI type XIV patient. However, both human and murine bone tissue with absence of TRIC-B demonstrate the same abnormalities of the osteocyte lacunae porosity and osteocyte lacuno-canalicular network, indicating disruption to the OLCN which is likely a general hallmark of OI bone.

Most infants with prenatal osteogenesis imperfecta diagnosis and poor prognosis survive: experience of a quaternary care osteogenesis imperfecta center

Osteogenesis imperfecta is a genetic condition with improperly or inadequately produced Type I collagen. Manifestations include bowing deformities, fractures, hydrocephalus, respiratory insufficiency, and feeding difficulty. Moderate or severe OI is often diagnosed prenatally based on ultrasound findings and genetic testing may be labeled as lethal. Here, we present 18 infants with moderate to severely presenting OI who received neonatal care at a single center over a 5 yr period, 10 of which were delivered at our institution. All 18 infants survived to neonatal discharge, with 7 infants requiring respiratory support and 9 infants requiring feeding support at discharge. Through Fisher Exact Test, Mann-Whitney U Test and backward elimination regression, we do not observe that lethal or possibly lethal diagnoses prenatally were correlated with medically relevant outcomes such as need for respiratory support at discharge or need for feeding support at discharge. Sixteen of the eighteen individuals are alive, with a minority requiring either respiratory or feeding support. With a multidisciplinary team approach to neonatal care, outcomes may be optimized. Infants formerly diagnosed with lethal OI may survive. Given our findings, and lack of correlation of prenatal assessments with survival and other medical outcomes, we recommend all families be given the option to pursue medical interventions.

Protein disulfide isomerase is essential for osteoblast differentiation in mice

Protein disulfide isomerase (PDI) is an oxidoreductase responsible for the formation, reduction and isomerization of disulfide bonds of nascent proteins in endoplasmic reticulum (ER). So far, the role of PDI in bone biology has never been characterized using genetically-modified animal models. In this study we generated osteoblast- specific PDI-deficient mice by crossing PDI-floxed (PDIfl/fl) mice with Osx-Cre mice. Compared with their littermate control PDIfl/fl mice, homozygous osteoblast-knockout mice (Osx-Cre/PDIfl/fl) were embryonically lethal, but heterozygous knockout mice (Osx-Cre/PDIfl/wt) displayed significantly pronounced growth retardation and reduced bone length. Besides, the decreases in bone density, osteoblast and osteoclast numbers, collagen fiber content and bone formation rate were observed in Osx-Cre/PDIfl/wt mice. Osteoblast precursors isolated from PDIfl/fl mice were infected with Cre recombinant adenovirus to produce PDI-deficient osteoblasts, followed by induction of differentiation. Osteoblasts deficient of PDI had decreased alkaline phosphatase activity, mineralizing capacity, and differentiation. Quantitative protein mass spectrometry analysis and immunoblotting showed that PDI deficiency markedly decreased the expression of the α-subunits of collagen prolyl 4-hydroxylase (C-P4H), including P4HA1, P4HA2 and P4HA3. These results demonstrate that PDI plays an essential role in osteoblast differentiation and bone formation and is required for the expression of the α-subunit of C-P4H in osteoblasts.

Cardiac health, type I collagen, and aging in the oim/oim mouse model of osteogenesis imperfecta and a cohort of adults with OI

Osteogenesis imperfecta (OI) is a heritable connective tissue disorder with marked skeletal fragility and increased recognition as a pleiotropic type I collagenopathy. The impact of OI-causing gene variants on cardiac health and lifespan is just beginning to be understood. To begin to investigate cardiac manifestations of OI-causing type I collagen variants, we utilized the osteogenesis imperfecta murine (oim/oim) model to examine survival with increased age, as well as cardiac function and collagen expression at 4 and 18 mo of age. We determined male oim/oim mice had 50% decreased survival by 18 mo of age compared with wild-type (WT) littermates. Cardiac magnetic resonance imaging and echocardiography revealed 18-mo-old male oim/oim mice had increased left ventricular end-diastolic and end-systolic volumes concomitant with decreased function, as well as the presence of aortic stenosis in a subset of 4- and 18-mo-old male oim/oim mice compared with WT littermates. Female oim/oim survival and cardiac function were equivalent to their WT counterparts. Cardiac evaluations of an adult patient cohort with OI corroborated increased incidences of valvular dysfunction in the patient population with OI, with much of the male cohort also presenting with altered left ventricular function. Little is known concerning the impact of OI-causing variants on patient cardiac health and the influence of sex and age. Using an OI mouse model, we determined that 18-mo-old male oim/oim mice have cardiac dysfunction with decreased lifespan, confirming the need for further investigations to understand pleiotropic extraskeletal manifestations and disease progression in osteogenesis imperfecta.NEW & NOTEWORTHY The heritable skeletal dysplasia, osteogenesis imperfecta (OI), recently recognized as a pleiotropic collagenopathy, shows growing evidence of cardiac involvement impacting lifespan. Evaluating cardiac function (magnetic resonance imaging and echocardiography) using an OI mouse model revealed increased left ventricular end-diastolic and end-systolic volumes concomitant with decreased function and reduced survival in 18-mo-old male OI mice. Additional cardiac evaluations of an adult patient cohort with OI corroborated increased incidences of valvular dysfunction in the patient population with OI.

Comprehensive Review of Osteogenesis Imperfecta: Current Treatments and Future Innovations

Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by bone fragility due to reduced bone quality, often accompanied by low bone mass, recurrent fractures, hearing loss, skeletal abnormalities, and short stature. Pathogenic variants in over 20 genes lead to clinical and genetic variability in OI, resulting in diverse symptoms and severity. Current management involves a multidisciplinary approach, including antiresorptive medications, physiotherapy, occupational therapy, and orthopedic surgery, which provide symptomatic relief but no cure. Advancements in gene therapy technologies and stem cell therapies offer promising prospects for long-lasting or permanent solutions. This review provides a comprehensive overview of OI's classification, pathogenesis, and current treatment options. It also explores emerging biotechnologies for stem cells and gene-targeted therapies in OI. The potential of these innovative therapies and their clinical implementation challenges are evaluated, focusing on their imminent success in treating bone disorders.

Risk of Pulmonary Diseases in Osteogenesis Imperfecta in Denmark: A Register-Based Cohort Study

BACKGROUND

Osteogenesis imperfecta (OI) is a rare hereditary disease mainly resulting in reduced or altered collagen type I. Collagen type I is a major constituent of the respiratory system, and normal collagen type I is vital for pulmonary tissue function.

RESEARCH QUESTION

Do patients with OI have increased admission rates resulting from pulmonary diseases compared with the general population?

STUDY DESIGN AND METHODS

This was a register-based nationwide cohort study including all patients with OI in Denmark and a reference population. From January 1, 1995, through December 31, 2018, we evaluated the rates of admissions resulting from asthma, COPD, and pneumonia as well as the use of bronchodilator drugs and antibiotics comparing individuals with OI with the reference population.

RESULTS

We included 862 individuals with OI and 4,283 people from the reference population covering 15,952 and 79,471 person-years of observation, respectively, in the two cohorts. The admissions rate (incidence rate [IR]) was highest in female patients with OI aged 65 years or older, with 56.3 admissions per 1,000 person-years and 29.4 admissions per 1,000 person-years in the reference population (amounting to an admissions incident rate ratio [IRR] of 1.91 [95% CI, 1.38-2.70]). The highest admission rate in male patients with OI was found among participants aged 0 to 18 years, with an IR of 30.4 per 1,000 person-years compared with an IR of 7.7 per 1,000 person-years in the reference population (IRR, 4.92 [95% CI, 3.79-6.38]). We found a higher proportion of long-acting and short-acting bronchodilator drug users in the OI cohort, but no increased use of antibiotics.

INTERPRETATION

Overall, the admission rates for respiratory diseases were low in the OI cohort, but a higher relative risk of hospitalizations resulting from respiratory disease compared with the general population. Timely diagnosis and treatment of respiratory complications in individuals with OI is warranted.

Oral Health-Related Quality of Life in Dutch Adults With Osteogenesis Imperfecta

OBJECTIVE

To explore the oral health-related quality of life and its possible risk factors among adults with Osteogenesis Imperfecta using the Oral Health Impact Profile (OHIP)-49 questionnaire. Secondary objectives were to investigate the impact of self-reported Osteogenesis Imperfecta, Dentinogenesis Imperfecta, and age on various dental parameters.

MATERIALS AND METHODS

A cross-sectional questionnaire was distributed online to 417 Dutch adults with Osteogenesis Imperfecta at three national referral centers. Multivariate linear regression was performed to identify indicators for OHIP-49 Scores. The effect of Osteogenesis Imperfecta, Dentinogenesis Imperfecta, and age on various dental parameters was investigated using logistic regressions (p < 0.05).

RESULTS

One hundred and fifty-five questionnaires (37.2%) were suitable for analysis. Osteogenesis Imperfecta type III was significantly associated with higher OHIP-49 scores as compared to type I. Symptoms of temporomandibular disorders, missing teeth or dentures also increased the OHIP-49 scores significantly. Osteogenesis Imperfecta type IV and increasing age were associated with missing teeth. There was a 31.94 times (95% CI: 8.56-119.13) higher odds of tooth fracture with self-reported Dentinogenesis Imperfecta.

CONCLUSIONS

Adults with Osteogenesis Imperfecta type III report a lower oral health-related quality of life compared to Osteogenesis Imperfecta type I adults.

Pleiotropic effects of a recessive Col1a2 mutation occurring in a mouse model of severe osteogenesis imperfecta

In Europe, approximately 85-90% of individuals with Osteogenesis Imperfecta (OI) have dominant pathogenic variants in the Col1a1 or Col1a2 genes whilst for Asian, especially Indian and Chinese cohorts, this ratio is much lower. This leads to decreased or abnormal Collagen type I production. Subsequently, bone formation is strongly reduced, causing bone fragility and liability to fractures throughout life. OI is clinically heterogeneous, with the severity ranging from mild to lethal depending on the gene and the type and location of the OI-causative variant and the subsequent effect on (pro) collagen type I synthesis. However, the specific effects on the phenotype and function of osteoblasts are not fully understood. To investigate this, one of the OI murine models was used, i.e. the oim/oim (OIM) mice, which closest resembling severely deforming OI in humans. We showed that in OIM, the Col1a2 mutation results in a multifactorial inhibition of the osteogenic differentiation and maturation as well as inhibition of osteoclastogenesis. The phenotype of differentiated OIM osteoblasts also differs from that of wild type mature osteoblasts, with upregulated oxidative cell stress and autophagy pathways. The extracellular accumulation of defective type I collagen fibres contributes to activation of the TGF-β signalling pathway and activates the inflammatory pathway. These effects combine to destabilise the balance of bone turnover, increasing bone fragility. Together, these findings identify the complex mechanisms underlying OI bone fragility in the OIM model of severe OI and can potentially enable identification of clinically relevant endpoints to assess the efficacy of innovative pro-osteogenic treatment for patients with OI.

Mastication and electrical activation in the masseter and anterior temporalis muscles of children and adolescents with osteogenesis imperfecta

PURPOSE

to characterize mastication and electrical activation of the masseter and anterior temporalis muscles in children and adolescents with osteogenesis imperfecta (OI), and relate results to guided occlusion and occlusal interference.

METHODS

This observational, analytical cross-sectional study included 22 subjects divided into mild OI (MOI) (type 1) (n=15) and moderate-to-severe OI (MSOI) (types 3, 4, and 5) (n=7) groups. The Orofacial Myofunctional Evaluation with Scores (OMES) form was used to evaluate the clinical aspects of mastication. Surface electromyography was performed on the masseter and anterior temporalis muscles at rest for 10 seconds and during maximum intercuspation, spontaneous chewing, and instructed chewing on the right and left sides. Additionally, the activation index and muscle symmetry were measured.

RESULTS

a preferentially unilateral chewing pattern was observed in 12 (54.5%) participants. Masticatory patterns did not influence electrical activation during any of the tasks, nor did occlusal guidance during maximum intercuspation or mastication. The percentage of muscle activation during maximal intercuspation approached half of the total activation during spontaneous chewing. In muscle activation indices, the MSOI group presented more atypical scores, while the MOI group scores seemed to be in line with reference values. The symmetry indices seemed to correspond to reference values, but the standard deviation and minimum and maximum values pointed to asymmetric results.

CONCLUSION

This study found that the OI population presented muscle imbalances, but the results did not allow us to define one pattern of change.

Challenges in managing osteogenesis imperfecta in a resource-limited setting: a case report

INTRODUCTION

Osteogenesis imperfecta is a rare inherited connective tissue disorder that results in excessive bone fragility due to defects in collagen production. The majority of osteogenesis imperfecta cases are inherited in an autosomal dominant pattern, and 17 genetic causes have been identified. Diagnosis is usually based on clinical presentation and low bone mineral density scores, while treatment involves a multidisciplinary approach using medical therapies such as bisphosphonates, vitamin C, and pamidronate. Recent research has also explored new therapies, including teriparatide, denosumab, and allele-specific silencing (Edelu et al. in Ann Med Health Sci Res 4(Suppl 1):S1-5, 2014; Bastos et al. in Einstein (São Paulo) 8:480-2, 2010; Van Dijk and Sillence in Am J Med Genet A 164A(6):1470-81, 2014; Subramanian and Viswanathan in Osteogenesis Imperfecta. In: StatPearls. Treasure Island (FL): StatPearls Publishing. http://www.ncbi.nlm.nih.gov/books/NBK536957/ . Accessed 2 Mar 2023, 2022).

CASE PRESENTATION

A 3-week-old female neonate of African ethnicity was delivered at term by emergency C-section due to two previous scars. The baby had an APGAR score of 7 at 5 minutes and a birth weight of 2.5 kg. The neonate had short and deformed limbs, a soft head, and bluish eyes. The neonate was diagnosed with osteogenesis imperfecta on the basis of clinical examination findings and radiological investigations, which showed multiple bony discontinuities at variable stages of healing in the limbs and ribs. The neonate was managed with supplemental oxygen by nasal prongs and intravenous antibiotics but unfortunately passed away before being reviewed by the orthopedic team.

CONCLUSION

This case report underscores the importance of early diagnosis of osteogenesis imperfecta and highlights the need for increased clinical awareness, specialized training, and resource allocation to improve outcomes for patients with rare genetic disorders in low-resource settings.

Risk of Gastrointestinal Diseases in Osteogenesis Imperfecta: A Nationwide, Register-Based Cohort Study

Osteogenesis imperfecta (OI) is a group of rare genetic disorders most commonly caused by reduced amount of biologically normal collagen type I, a structural component of the gastrointestinal tract and abdominal wall. The risk of gastrointestinal (GI) disease in individuals with OI is not well understood, despite GI complaints being frequently reported by the OI population. To investigate the risk of GI diseases in individuals with OI. A Danish nationwide register-based cohort study utilizing data from the Danish National Patient Register and the Danish National Prescription Register. All individuals registered with an OI diagnosis in Denmark from 1995 through 2018, along with a reference population matched 1:5 based on sex, birth year, and month. Sub-hazard ratios (SHR) for peptic ulcer disease, diverticular disease, gastrointestinal cancers, intestinal obstruction with ileus, constipation, abdominal wall hernia, and other reasons for abdominal discomfort. The study included 864 individuals with OI (472 women) and 4,276 in the reference population (2,332 women). The SHR was significantly increased for ulcer (3.28 [95% CI 2.21-4.28]), constipation (2.67 [1.91-3.74]), and hernia (among women: 1.85 [1.22-2.80]). Higher SHRs were also observed for inflammatory bowel disease, biliary and pancreatic diseases, appendicitis, and unspecified abdominal pain. SHRs were not statistically significantly increased for diverticular disease, gastrointestinal cancers, intestinal obstruction with ileus, kidney stones or hemorrhoid disease. Individuals with OI have a higher risk of peptic ulcer disease, constipation, hernia among women, inflammatory bowel diseases, biliary and pancreatic diseases, appendicitis, and unspecified abdominal pain, compared with the general population.

Blue Sclera to Brittle Bones: A Rare Case of Osteogenesis Imperfecta With Dentinogenesis Imperfecta and Nephrocalcinosis

Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by bone fragility. Its association with dentinogenesis imperfecta (DI) is well documented, but the concurrent presentation with nephrocalcinosis is uncommon and poorly understood. We documented the case of an 18-year-old male presenting with a triad of OI, DI, and nephrocalcinosis. The patient exhibited characteristic features including blue sclera, multiple fractures, dental abnormalities, bowing of long bones, a short stature, and biochemical evidence of altered calcium metabolism. Genetic testing revealed mutations in COL1A1, confirming the diagnosis of OI Type I. This case highlights the importance of comprehensive evaluation in OI patients, emphasizing the need for dental and renal assessment. The presence of nephrocalcinosis in OI demands further investigation into the mechanisms of calcium dysregulation in disorders of these kinds.

Case Series of 6 Fetuses With Osteogenesis Imperfecta Type II: A Retrospective Study of Heart Pathology

INTRODUCTION

Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by bone fragility. While skeletal manifestations are well documented, few studies have explored the effect of OI on the fetal heart. This retrospective case series investigates cardiac pathology in OI type II fetuses, aiming to address this gap.

METHODS

Medical records and autopsy reports of 6 genetically confirmed OI type II cases were examined. Fetuses had pathogenic variants in COL1A1 or PPIB, inducing structural defects in collagen type I. In addition to hematoxylin and eosin and Elastic van Gieson staining, the expression of collagen type I, COL1A1 and COL1A2 chains was examined by immunohistochemistry.

RESULTS

Immunohistochemistry confirmed robust expression of collagen type I throughout the heart. Five fetuses had normal heart weight, while 1 had a low heart weight in the context of generalized growth retardation. None displayed structural heart anomalies.

CONCLUSION

This study reveals robust collagen type I expression in the hearts of OI type II fetuses without structural anomalies. We hypothesize that collagen type I abnormalities may not be causative factors for heart anomalies during early embryonic development. Instead, their impact may be conceivably related to an increased susceptibility to degenerative changes later in life.

Corneal Alterations in Patients with Osteogenesis Imperfecta: An in vivo Corneal Confocal Microscopy Study

Purpose

Osteogenesis imperfecta (OI) is a rare hereditary disorder of the connective tissue. Despite recent attention to corneal abnormalities in OI, understanding remains limited. This study aimed to comprehensively evaluate corneal changes in a large sample of OI patients compared to controls using in vivo confocal microscopy (IVCM).

Patients and Methods

Nineteen OI patients (mean age: 34.0 ± 16.00 years; 9 females, 10 males) and 20 healthy controls (mean age: 35.5 ± 12.00; 12 females, 8 males) were included, matched for age and gender. The integrity of corneal cell layers, with a focus on Bowman's layer and sub-epithelial stroma, was evaluated. Additionally, we conducted a quantitative analysis of the corneal sub-basal nerve plexus (CSNP), measuring nerve fiber density (NFD), nerve branch density (NBD), nerve fiber length (NFL), and dendritic cells (DCs) density. Clinical parameters including blue discoloration of the sclera, corneal thickness and sensitivity were also evaluated.

Results

Bowman's layer alterations were observed in 42.11% of OI patients. NFD was significantly reduced in OI patients (27,3±6.98 vs controls 37.85±13,74 fiber/mm2; p-value=0.005). NBD and NFL were lower in OI patients but did not reach statistical significance (p=0.650 and p=0.120, respectively). DCs density was higher in OI patients than controls (11,37 ± 12.79 vs 2.09±2,91 cells/mm2; p-value < 0.001). Corneal thickness and sensitivity were significantly reduced in OI patients compared to controls (p<0.001, p=0.001, respectively). OI patients with blue sclera or abnormal Bowman's layer exhibited even lower central corneal thickness (CCT) (p=0.010, p=0.005, respectively).

Conclusion

OI patients demonstrated Bowman's layer abnormalities, neuropathic changes and higher inflammatory cell count. These results suggest potential corneal complications, and hold promise for diagnostic applications and intervention strategies in OI.

The impact of obesity on sleep, pulmonary and chest wall restriction in Osteogenesis Imperfecta: a pilot study

INTRODUCTION

Osteogenesis Imperfecta (OI) is characterised by brittle bones, severe skeletal deformities, low sleep quality, and restricted breathing. We aimed to distinguish how disease and obesity affect these results.

METHODS

According to BMI, we considered four groups of peer adults (median age: 35.0 years): 13 subjects affected by moderate or severe OI without obesity (OIno), 14 affected by moderate or severe OI with obesity (OIob), 10 without obesity not affected by OI (OB) and 10 without obesity not affected by OI.

RESULTS

Obstructive Sleep Apnoea Syndrome was diagnosed in 4 OIno (30%) and 9 OIob (64%). Restricted lung pattern (z-score of total lung capacity < - 1.64) was diagnosed in 10 OIno (77%); 9 OIob (65%), and 1 OB (10%) subjects. In the seated position, OIob breathed with reduced tidal volume and higher respiratory rate, resulting in hypoventilation. Both OIno and OIob were characterised by rapid and shallow breathing and lower ribcage expansion (negative in 3 (23%) OIno and 3 (21%) OIob). In the supine position, the ventilatory pattern was similar among the four groups, while both OIno and OIob were characterised by reduced ribcage contribution, which was negative in 6 (46%) OIno, 11 (78%) OIob and 1 (10%) OB.

CONCLUSIONS

This is a pilot study on a small sample, the findings and conclusions apply only to this study population. The preliminary results suggest that in subjects with moderate or severe OI per se implies (1) a 30% prevalence of obstructive sleep apnoea syndrome, (2) a restricted lung pattern, (3) a lower ribcage expansion, and (4) rapid and shallow breathing in the seated position. The additional impacts of obesity on OI seem to determine (1) a higher incidence of obstructive sleep apnoea syndrome, (2) hypoventilation in the seated position, and (3) a higher incidence of paradoxical breathing lying supine. Reversing obesity in OI is even more challenging as knowledge of the diet and the physical activity suited for these patients is still scarce.

Molecular Genetic Diagnosis with Targeted Next Generation Sequencing in a Cohort of Turkish Osteogenesis Imperfecta Patients and their Genotype-phenotype Correlation

Objective

Osteogenesis imperfecta (OI) consists of a group of phenotypically and genetically heterogeneous connective tissue disorders that share similar skeletal anomalies causing bone fragility and deformation. The aim was to investigate the molecular genetic etiology and determine the relationship between genotype and phenotype in OI patients using targeted next-generation sequencing (NGS).

Methods

A targeted NGS analysis panel (Illumina TruSight One) containing genes involved in collagen/bone synthesis was performed on the Illumina Nextseq550 platform in patients with a confirmed diagnosis of OI.

Results

Fifty-six patients (female/male: 25/31) from 46 different families were included. Consanguinity was noted in 15 (32.6%) families. Based on Sillence classification 18 (33.1%) were type 1 OI, 1 (1.7%) type 2, 26 (46.4%) type 3 and 11 (19.6%) type 4. Median body weight was -1.1 (-6.8, - 2.5) standard deviation scores (SDS), and height was -2.3 (-7.6, - 1.2) SDS. Bone deformity affected 30 (53.5%), while 31 (55.4%) were evaluated as mobile. Thirty-six (60.7%) had blue sclera, 13 (23.2%) had scoliosis, 12 (21.4%) had dentinogenesis imperfecta (DI), and 2 (3.6%) had hearing loss. Disease-causing variants in COL1A1 and COL1A2 were found in 24 (52.1%) and 6 (13%) families, respectively. In 8 (17.3%) of the remaining 16 (34.7%) families, the NGS panel revealed disease-causing variants in three different genes (FKBP10, SERPINF1, and P3H1). Nine (23.6%) of the variants detected by NGS panel had not previously been reported and were also classified as pathogenic based on American College of Medical Genetics guidelines pathogenity scores. In ten (21.7%) families, a disease-related variant was not found in any of the 13 OI genes on the panel.

Conclusion

Genetic etiology was found in 38 (82.6%) of 46 families by targeted NGS analysis. Furthermore, nine new variants were identified in known OI genes which were classified as pathogenic by standard guidelines.

Trabecular bone scores in children with osteogenesis imperfecta respond differently to bisphosphonate treatment depending on disease severity

Introduction

Osteogenesis imperfecta (OI) is a congenital skeletal disorder characterized by bone fragility. Bisphosphonates (BISs) have become the mainstream treatment in children with OI. However, an optimal treatment protocol has not yet been established, while BIS treatment tends to be administered to normalize bone mineral density (BMD). Bone quality is an important component of bone strength. The trabecular bone score (TBS) is a quantitative measure of the microstructure that affects bone quality. This study investigated the TBS during BIS treatment in children with OI.

Materials and methods

Twenty-nine children with OI were enrolled and classified into two groups: mild (type 1) and moderate to severe (types 3 and 4). Dual-energy x-ray absorptiometry images were retrospectively analyzed for TBS calculation. The relationship between the areal BMD (aBMD), its Z-score, height-adjusted BMD (BMDHAZ) Z-score, TBS, and TBS Z-score with the treatment duration was assessed for each group.

Results

In the mild group, the aBMD, its Z-score, and BMDHAZ Z-score showed a significant positive correlation with treatment duration (r = 0.68, 0.68, 0.72, respectively, p < 0.01). The TBS Z-score tended to increase with treatment duration, albeit without reaching significance. In the moderate to severe group, the TBS Z-score showed a significant positive correlation with treatment duration (r = 0.48, p < 0.01), in contrast to the aBMD Z-score, which did not increase. Finally, the BMDHAZ Z-score only showed a weak positive correlation with treatment duration (r = 0.37, p < 0.01).

Conclusion

Because BIS affect the BMD and TBS differently based on the severity of OI, treatment goals may need to be stratified by disease severity.

Bone Quality and Mineralization and Effects of Treatment in Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a rare congenital bone dysplasia characterized by high fracture rates and broad variations in clinical manifestations ranging from mild to increasingly severe and perinatal lethal forms. The underlying mutations affect either the synthesis or processing of the type I procollagen molecule itself or proteins that are involved in the formation and mineralization of the collagen matrix. Consequently, the collagen forming cells, the osteoblasts, become broadly dysfunctional in OI. Strikingly, hypermineralized bone matrix seems to be a frequent feature in OI, despite the variability in clinical severity and mutations in the so far studied different forms of human OI. While the causes of the increased mineral content of the bone matrix are not fully understood yet, there is evidence that the descendants of the osteoblasts, the osteocytes, which play a critical role not only in bone remodeling, but also in mineralization and sensing of mechanical loads, are also highly dysregulated and might be of major importance in the pathogenesis of OI. In this review article, we firstly summarize findings of cellular abnormalities in osteoblasts and osteocytes, alterations of the organic matrix, as well as of the microstructural organization of bone. Secondly, we focus on the hypermineralization of the bone matrix in OI as observed in several different forms of human OI as well as in animal models, its measurement and potential mechanical implications and its effect on the bone mineral density measured by dual X-ray absorptiometry. Thirdly, we give an overview of established medication treatments of OI and new approaches with a focus of their known or possible effects on the bone material, particularly on bone matrix mineralization.

Osteogenesis Imperfecta: Skeletal and Non-skeletal Challenges in Adulthood

Osteogenesis imperfecta (OI) is a Mendelian connective tissue disorder associated with increased bone fragility and other clinical manifestations most commonly due to abnormalities in production, structure, or post-translational modification of type I collagen. Until recently, most research in OI has focused on the pediatric population and much less attention has been directed at the effects of OI in the adult population. This is a narrative review of the literature focusing on the skeletal as well as non-skeletal manifestations in adults with OI that may affect the aging individual. We found evidence to suggest that OI is a systemic disease which involves not only the skeleton, but also the cardiopulmonary and gastrointestinal system, soft tissues, tendons, muscle, and joints, hearing, eyesight, dental health, and women's health in OI and potentially adds negative affect to health-related quality of life. We aim to guide clinicians as well as draw attention to obvious knowledge gaps and the need for further research in adult OI.

Orthopedic Surgery in Osteogenesis Imperfecta in Adults

Osteogenesis imperfecta is a genetic disorder, mainly characterized by bone fragility. In adult with osteogenesis imperfecta, surgical treatment may be indicated as an emergency procedure in the event of a fracture, or as a scheduled procedure in case of patient functional impairment due to many causes, such as persistent pain, complex bone deformities, and degenerative arthropathies. In all cases, a multidisciplinary approach is recommended. It is essential to consider the patient's characteristics and expectations regarding treatment, as well as the local conditions, which may be complex due to the poor bone quality, bone deformity, and the presence of hardware implanted during childhood. The procedure can be very complex and challenging and each patient is a unique case. An accurate preoperative planning is mandatory to select the appropriate surgical technique, which can be either conservative or prosthetic, and to evaluate its feasibility and the risk-benefit ratio. The aim is to improve the patient's quality of life and autonomy as long as possible.

A Dyadic Nosology for Osteogenesis Imperfecta and Bone Fragility Syndromes 2024

In 2023 following extensive consultation with key stakeholders, the expert Nosology Working Group of the International Skeletal Dysplasia Society (ISDS) published the new Dyadic Nosology for Genetic Disorders of the Skeleton. Some 770 entities were delineated associated with 552 genes. From these entities, over 40 genes resulting in distinct forms of Osteogenesis Imperfecta (OI) and Bone Fragility and/or Familial Osteoporosis were identified. To assist clinicians and lay stake holders and bring the considerable body of knowledge of the matrix biology and genomics to people with OI as well as to clinicians and scientists, a dyadic nosology has been recommended. This combines a genomic co-descriptor with a phenotypic naming based on the widely used Sillence nosology for the OI syndromes and the many other syndromes characterized in part by bone fragility.This review recapitulates and explains the evolution from the simple Congenita and Tarda subclassification of OI in the 1970 nosology, which was replaced by the Sillence types I-IV nosology which was again replaced in 2009 with 5 clinical groups, type 1 to 5. Qualitative and quantitative defects in type I collagen polypeptides were postulated to account for the genetic heterogeneity in OI for nearly 30 years, when OI type 5, a non-collagen disorder was recognized. Advances in matrix biology and genomics since that time have confirmed a surprising complexity both in transcriptional as well as post-translational mechanisms of collagens as well as in the many mechanisms of calcified tissue homeostasis and integrity.

Surgical treatment of scoliosis in patients with osteogenesis imperfecta: a single institution case series

BACKGROUND

Osteogenesis imperfecta (OI) is a connective tissue disorder characterized by skeletal deformities, bone fragility, and spinal complications. Various studies' insights underscored the impact of scoliosis on pulmonary function, positive outcomes with spinal fusion, and improved functional abilities post-surgery. However, partial loss of correction remains inevitable.

METHODS

This study examines six surgically treated OI patients with scoliosis. Surgical intervention using a posterior approach with pedicle screws and hooks aimed to correct spinal deformities. Preoperative, postoperative, and follow-up radiological assessments were conducted, revealing significant reductions in scoliotic angles post-surgery.

RESULTS

Complications included infections and proximal junctional kyphosis requiring revision surgeries. Despite the challenges posed by poor bone quality and implant stability, no implant failures occurred in this series. Ponte osteotomies at the apex of deformity aided in corrective maneuvers.

CONCLUSION

Surgical treatment of scoliosis in patients affected by OI is challenging and may be associated with perioperative and postoperative complications. Ponte osteotomy may improve the correction and reduce necessary force at the time of correction.

Analyses of Osteogenesis Imperfecta in South Korea Using the Nationwide Health Insurance Service Claim Data: A Propensity Score-Matched Study

Osteogenesis imperfecta (OI) is the most common inherited form of bone fragility and includes a heterogeneous group of genetic disorders that most commonly result from defects associated with type I collagen. Although genetic analyses have been developed, nationwide research on the incidence and associated fractures in OI is lacking. This study aimed to investigate the patterns of OI prevalence, incidence, fracture rate, etc. in South Korea using National Health Insurance Service (NHIS) claims data. We found 1596 patients newly diagnosed with OI between March 2002 and February 2020. We evaluated the incidence, prevalence, and history of fractures, fracture site, prescription of anti-osteoporosis drugs, etc. To compare medical costs, fracture rates, and scoliosis rates, we created a control group comprising patients without OI using 1:1 propensity score matching. The prevalence of OI increased slightly each year, with an annual incidence of 20.20 per 100,000 live births. Mean fracture frequency in OI patients was 17 (2-32) times per patient and the most frequent fracture site was the lower leg. A total of 21.4% patients were prescribed anti-osteoporosis drugs, and the most popular drug was pamidronate. After 1:1 propensity score matching, in terms of scoliosis, OI patients had a 3.91 times higher prevalence of scoliosis than in healthy patients which was statistically significant. The sum of medical care expenses for patients with OI was 3.5 times higher than that for patients without OI. We identified nationwide trends in OI occurrence, fractures, and medication use. This study also highlighted the real-world data of scoliosis and medical costs compared to the control group.

Sensing the future: A review on emerging technologies for assessing and monitoring bone health

Bone health is crucial at all stages of life. Several medical conditions and changes in lifestyle affect the growth, structure, and functions of bones. This may lead to the development of bone degenerative disorders, such as osteoporosis, osteoarthritis, rheumatoid arthritis, etc., which are major public health concerns worldwide. Accurate and reliable measurement and monitoring of bone health are important aspects for early diagnosis and interventions to prevent such disorders. Significant progress has recently been made in developing new sensing technologies that offer non-invasive, low-cost, and accurate measurements of bone health. In this review, we have described bone remodeling processes and common bone disorders. We have also compiled information on the bone turnover markers for their use as biomarkers in biosensing devices to monitor bone health. Second, this review details biosensing technology for bone health assessment, including the latest developments in various non-invasive techniques, including dual-energy X-ray absorptiometry, magnetic resonance imaging, computed tomography, and biosensors. Further, we have also discussed the potential of emerging technologies, such as biosensors based on nano- and micro-electromechanical systems and application of artificial intelligence in non-invasive techniques for improving bone health assessment. Finally, we have summarized the advantages and limitations of each technology and described clinical applications for detecting bone disorders and monitoring treatment outcomes. Overall, this review highlights the potential of emerging technologies for improving bone health assessment with the potential to revolutionize clinical practice and improve patient outcomes. The review highlights key challenges and future directions for biosensor research that pave the way for continued innovations to improve diagnosis, monitoring, and treatment of bone-related diseases.

Fetal therapies - (Stem cell transplantation; enzyme replacement therapy; in utero genetic therapies)

Advances in ultrasound and prenatal diagnosis are leading an expansion in the options for parents whose fetus is identified with a congenital disease. Obstetric diseases such as pre-eclampsia and fetal growth restriction may also be amenable to intervention to improve maternal and neonatal outcomes. Advanced Medicinal Therapeutic Products such as stem cell, gene, enzyme and protein therapies are most commonly being investigated as the trajectory of treatment for severe genetic diseases moves toward earlier intervention. Theoretical benefits include prevention of in utero damage, smaller treatment doses compared to postnatal intervention, use of fetal circulatory shunts and induction of immune tolerance. New systematic terminology can capture adverse maternal and fetal adverse events to improve safe trial conduct. First-in-human clinical trials are now beginning to generate results with a focus on safety first and efficacy second. If successful, these trials will transform the care of fetuses with severe early-onset congenital disease.

Osteogenesis imperfecta in Peruvian children: Phenotypic and therapeutic insights from a pediatric hospital

Osteogenesis imperfecta (OI) is a genetic disorder of the connective tissue that is characterized by high bone fragility. It has a worldwide incidence of 1 in 10,000. The diagnosis is mainly clinical-radiological. Treatment is based on the use of bisphosphonates and orthopedic surgeries. The objective of this study was to establish the clinical, radiological, and therapeutic characteristics of OI in pediatric patients of a national reference pediatrics institute. This was conducted through a descriptive and retrospective analysis. All patients under 18 years of age with a diagnosis of OI treated at the Instituto Nacional de Salud del Niño de Breña (INSN-Breña) between 2010 and 2021 were included. In total, 91 patients with OI were studied, more than half of whom were male. A total of 93.4% had a history of fractures, 72.5% had blue sclera, 39.6% had bowed legs and 20.9% had dentinogenesis imperfecta. The minimum-maximum value of fractures was 0-18. A total of 75.8% of patients started treatment with bisphosphonates and 41.8% used adjuvant medications. Less than 50% of patients required surgical treatment. Osteogenesis imperfecta is a genetic and chronic pathology. The use of the Van Dijk severity grade and the Aglan severity scale is simple to apply and therefore should be used to improve the classification of groups with the highest risk of fractures and response to treatment. Due to the low incidence of this disease, it is important to raise awareness and increase the research volume on this subject.

Craniofacial Effects of Zoledronic Acid on the Osteogenesis Imperfecta Mouse (-/-) Model of Severe Osteogenesis Imperfecta

Background: Osteogenesis imperfecta (OI) is a rare genetic disorder affecting mainly type I collagen, which leads to bone fragility and deformities. OI patients also present craniofacial abnormalities such as macrocephaly and malocclusion. Recently, craniofacial dysmorphism was highlighted in the osteogenesis imperfecta mouse (oim), a validated model of the most severe form of OI. This study explores the impact of zoledronic acid (ZA), commonly administered to OI patients to increase bone mass and mechanical strength, on oim craniofacial structure. Methods: Fifteen oim received a single intravenous ZA injection (100 µg/kg) at 5 weeks (ZA group), while fifteen remained untreated (control). Before euthanasia at 14 weeks, in vivo computed tomography provided craniometric data. Post-euthanasia, heads underwent peripheral Quantitative Computed Tomography (pQCT); coronal decalcified sections through temporomandibular joints were analyzed (n = 6/mouse) after Masson's trichrome staining (3 sections) or under polarized light to study collagen birefringence (3 sections). Results: In vivo craniometry highlighted the positive effect on vertical growth in ZA oim models as compared to untreated ones, with significant increases in mandibular length and incisor height and without any change in transversal dimensions. The pQCT scans showed the significantly higher total mineral density and cortical mineral density of the mandibular ramus in the ZA than the untreated group. Via microscopic analysis, the cranial vault was thicker and the collagen birefringence was higher in the ZA group than in the untreated group, but differences were not significant. Conclusion: To conclude, ZA had some beneficial effects on craniofacial vertical height and ramus density and, to a lower extent, on vault thickness, while transversal dimensions did not seem to be influenced by ZA intake. These data emphasize the need to consider the whole skeleton when treating OI patients.

Dental Abnormalities in Osteogenesis Imperfecta: A Systematic Review

Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by fragile bones and skeletal deformities. Individuals with OI may have dental abnormalities such as dentinogenesis imperfecta (DI) type I, malocclusions, and unerupted or missing teeth. This review comprehensively examines these dental abnormalities to assess their prevalence among the OI population and explore potential differences across different clinical types of OI and pathogenic variants. In accordance with the PRISMA guidelines, a systematic literature search in PubMed, Embase, and Web of Science was conducted that included articles up to June 2024. Out of 672 articles screened, 34 were included. The included studies confirmed that dental abnormalities are prevalent in OI, with DI prevalence ranging from approximately 20 to 48%. Those with a more severe skeletal phenotype (OI type III/IV) exhibited more dental abnormalities than those with a milder skeletal phenotype (OI type I). Notably, OI type V individuals generally do not have DI, although a few isolated cases have been reported. The prevalence of occlusion types varied: Class I occlusion ranged from 14.8 to 50% and Class II malocclusion ranged from 0 to 37.5%, while Class III malocclusion from 4.1 to 84%. This differs from the general population, where Class III malocclusion is typically the least common. Open bites, cross-bites, and unerupted and missing teeth are also commonly reported, particularly in OI types III and IV. This review emphasizes the need for comprehensive dental examinations in OI due to the high prevalence of dental abnormalities. Additionally, the review draws attention to the lack of clear guidelines for diagnosing DI.

Skeletal pathology in mouse models of Gould syndrome is partially alleviated by genetically reducing TGFβ signaling

Skeletal defects are hallmark features of many extracellular matrix (ECM) and collagen-related disorders. However, a biological function in bone has never been defined for the highly evolutionarily conserved type IV collagen. Collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) form α1α1α2 (IV) heterotrimers that represent a fundamental basement membrane constituent present in every organ of the body, including the skeleton. COL4A1 and COL4A2 mutations cause Gould syndrome, a variable and clinically heterogenous multisystem disorder generally characterized by the presence of cerebrovascular disease with ocular, renal, and muscular manifestations. We have previously identified elevated TGFβ signaling as a pathological insult resulting from Col4a1 mutations and demonstrated that reducing TGFβ signaling ameliorate ocular and cerebrovascular phenotypes in Col4a1 mutant mouse models of Gould syndrome. In this study, we describe the first characterization of skeletal defects in Col4a1 mutant mice that include a developmental delay in osteogenesis and structural, biomechanical and vascular alterations of mature bones. Using distinct mouse models, we show that allelic heterogeneity influences the presentation of skeletal pathology resulting from Col4a1 mutations. Importantly, we found that TGFβ target gene expression is elevated in developing bones from Col4a1 mutant mice and show that genetically reducing TGFβ signaling partially ameliorates skeletal manifestations. Collectively, these findings identify a novel and unsuspected role for type IV collagen in bone biology, expand the spectrum of manifestations associated with Gould syndrome to include skeletal abnormalities, and implicate elevated TGFβ signaling in skeletal pathogenesis in Col4a1 mutant mice.

Reviewing hereditary connective tissue disorders: Proposals of harmonic medicolegal assessments

Hereditary connective tissue disorders (HCTDs) are a heterogeneous group of inherited diseases. These disorders show genetic mutations with loss of function of primary components of connective tissue, such as collagen and elastic fibers. There are more than 200 conditions that involve hereditary connective tissue disorders, while the most known are Marfan syndrome, Osteogenesis Imperfecta, and Ehlers-Danlos syndromes. These disorders need continuous updates, multidisciplinary skills, and specific methodologic evaluations sharing many medicolegal issues. Marfan syndrome and Ehlers-Danlos syndromes show a high risk of early sudden death. As a consequence of this, postmortem genetic testing can identify novel genotype-phenotype correlations which help the clinicians to assess personalized cardiovascular screening programs among the ill subjects. Genetic testing is also essential to identify children suffering from Osteogenesis Imperfecta, especially when a physical abuse is clinically suspected. However, this is a well-known clinical problem even though there are still challenges to interpret genetic data and variants of unknown significance due to the current extensive use of new genetic/genomic techniques. Additionally, the more significant applications and complexities of genomic testing raise novel responsibilities on the clinicians, geneticists, and forensic practitioners as well, increasing potential liability and medical malpractice claims. This systematic review provides a detailed overview on how multidisciplinary skills belonging to clinicians, medicolegal consultants, radiologists, and geneticists can cooperate to manage HCTDs from autopsy or clinical findings to genetic testing. Thus, technical aspects need to be addressed to the medicolegal community since there is no consensus works or guidelines which specifically discuss these issues.

Assessment of the Retinal Nerve Fibre Layer, Retina, and Choroid in Osteogenesis Imperfecta

BACKGROUND

Osteogenesis imperfecta (OI) is a genetic disorder in which there are problems in tissues containing type I collagen, predominantly the cornea and sclera in the eye. Although there are many studies on problems with the anterior segment of the eye in patients with OI, studies on posterior structures are limited. Involvement of the sclera may affect the retinal nerve fibre layer (RNFL), which is indirectly related to intraocular pressure. In addition, the retina and choroid containing type I collagen may be affected. The aim of the study was to compare the posterior segment structures of the eye, including the RNFL, retina, and choroid, in patients with OI to those of healthy control subjects.

METHODS

This cross-sectional study recruited 19 patients with OI, as well as 22 age- and gender-similar healthy control subjects. Measurements of the RNFL, retina, and choroid were obtained with optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering, Heidelberg, Germany).

RESULTS

Patients with OI (mean age 14.32 ± 5.08 years) and the control group (mean age 13.73 ± 3.56 years) had similar age, refractive error, and intraocular pressure values (p > 0.05). There was no difference between groups in terms of RNFL thickness, including the superonasal, nasal, inferonasal, inferotemporal, temporal, and superotemporal sectors, retinal thickness, and choroidal thickness from five different locations (p > 0.05, for all).

CONCLUSION

According to these results, OI does not clinically affect the RNFL, retina, and choroid in childhood.

Polarization-sensitive optical coherence tomography and scleral collagen fiber orientation in osteogenesis imperfecta

Osteogenesis imperfecta (OI), a rare genetic connective tissue disorder, primarily arises from pathogenic variants affecting the production or structure of collagen type I. In addition to skeletal fragility, individuals with OI may face an increased risk of developing ophthalmic diseases. This association is believed to stem from the widespread presence of collagen type I throughout various parts of the eye. However, the precise consequences of abnormal collagen type I on different ocular tissues remain unknown. Of particular significance is the sclera, where collagen type I is abundant and crucial for maintaining the structural integrity of the eye. Recent research on healthy individuals has uncovered a unique organizational pattern of collagen fibers within the sclera, characterized by fiber arrangement in both circular and radial layers around the optic nerve head. While the precise function of this organizational pattern remains unclear, it is hypothesized to play a role in providing mechanical support to the optic nerve. The objective of this study is to investigate the impact of abnormal collagen type I on the sclera by assessing the fiber organization near the optic nerve head in individuals with OI and comparing them to healthy individuals. Collagen fiber orientation of the sclera was measured using polarization-sensitive optical coherence tomography (PS-OCT), an extension of the conventional OCT that is sensitive to materials that exhibit birefringence (axial changes in light refraction). Birefringence was quantified and used as imaging contrast to extract collagen fiber orientation as well as the thickness of the radially oriented scleral layer. Three individuals with OI, exhibiting different degrees of disease severity, were assessed and analyzed, along with seventeen healthy individuals. Mean values obtained from individuals with OI were descriptively compared to those of the healthy participant group. PS-OCT revealed a similar orientation pattern of scleral collagen fibers around the optic nerve head between OI individuals and healthy individuals. However, two OI participants exhibited reduced mean birefringence of the radially oriented scleral layer compared to the healthy participant group (OI participant 1 oculus dexter et sinister (ODS): 0.34°/μm, OI participant 2: ODS 0.26°/μm, OI participant 3: OD: 0.29°/μm, OS: 0.28°/μm, healthy participants: ODS 0.38 ± 0.05°/μm). The radially oriented scleral layer was thinner in all OI participants although within ±2 standard deviations of the mean observed in healthy individuals (OI participant 1 OD: 101 μm, OS 104 μm, OI participant 2: OD 97 μm, OS 98 μm, OI participant 3: OD: 94 μm, OS 120 μm, healthy participants: OD 122.8 ± 13.6 μm, OS 120.8 ± 15.1 μm). These findings imply abnormalities in collagen organization or composition, underscoring the necessity for additional research to comprehend the ocular phenotype in OI.

Pregnancy complications and birth outcome in patients with osteogenesis imperfecta - A population-based register study

OBJECTIVE

Patients with Osteogenesis Imperfecta (OI) have varying degrees of bone fragility and increased fracture rates. There is a paucity of data related to complications to pregnancies in patients with OI and to their offspring. With this study we aim to evaluate the risk of complications to pregnancies, delivery, and offspring in pregnancies where the mother or father have OI.

DESIGN

Nationwide, register-based, cohort study.

SETTING

Danish health register-based data.

POPULATION

All pregnancies registered in the Danish health registers where one parent has OI and a reference population of all other pregnancies in the general population from 1997 to 2018.

METHODS

Descriptive epidemiology MAIN OUTCOME MEASURES: Pregnancy and delivery complications (e.g. prevalence of pre-eclampsia, eclampsia and perinatal haemorrhage), and complications in the offspring (e.g. prevalence of low birth weight, low Apgar Score, need of CPAP or NICU, prevalence of congenital malformations (using the EUROCAT classification), incidence of osteogenesis imperfecta, prevalence of birth related fractures and hospital contacts during the first year of life) from pregnancies with parental OI.

RESULTS

We identified 433 OI related pregnancies among 134 mothers with OI and 73 fathers with OI. The rates of pregnancy and delivery complications were similar between the OI cohorts and the reference population. More (31 % vs 19 %) children were delivered by caesarean section in the OI cohort than in the reference population.

CONCLUSION

Pregnancies, where one parent have OI, result in live births to term with very few complications.

Evaluation of the Nordic Musculoskeletal Questionnaire for Measuring Prevalence and the Consequence of Pain in a Danish Adult OI Population: A Pilot Study

Pain is a challenge in persons with OI and causes much concern in the Osteogenesis Imperfecta (OI) population. We aim to evaluate the usability of the Nordic Musculoskeletal Questionnaire (NMQ) to identify painful sites in adults with OI and to describe the occurrence of musculoskeletal (MSK) pain and its impact on their work and daily activities. This cross-sectional pilot study uses the OI-NMQ to study MSK pain prevalence in nine separate anatomical regions (neck, upper back, lower back, shoulder, elbow, hand/wrist, hip, knee, and ankle/foot) and its impact on regular work and daily activities in adults with OI. The questionnaire was distributed among participants of the 2023 annual meeting of The Danish OI Society. The response rate was 68%, and all participants considered the OI-NMQ helpful in assessing the presence of pain and its consequences. The analysis included 27 adults with OI type I, III, or IV above 18 years. Among all 27 participants, MSK pain was present in 15-56% of the 9 sites within the last 7 days and 33-89% of the nine anatomical regions during the last 12 months. In 7-48% of all the participants, their regular work and daily activities had been affected by the presence of MSK pain. The OI-NMQ was feasible in assessing MSK pain among adults with OI and displayed a high prevalence of MSK pain with a moderate impact on their regular work and daily activities in this OI population. A larger and repeated measurement of MSK pain in adults with OI is needed to confirm these results.

Integrative Management of Bone Deformities in Osteogenesis Imperfecta: A Case Report on Zoledronic Acid and Corrective Osteotomy

Osteogenesis imperfecta (OI) is a hereditary genetic condition characterized by brittle bones that are easily broken. Surgical intervention is necessary frequently to treat fractures and deformities in patients diagnosed with OI. In this case, we discuss a case of a nine-year-old male child diagnosed with OI. This boy was previously operated on one year back for a femur fracture with osteotomy and internal fixation with nails, followed by implant removal at a later stage almost one year later. This boy was brought to our hospital with convex deformities of femur and tibia. Upon evaluation and review of this boy's case, the decision was made to administer a zoledronic acid infusion cycle over three days to enhance bone strength. Following this pharmacological therapy, this patient was planned for corrective osteotomy and internal fixation of the femur. This case underscores the complexities of managing OI and also highlights the importance of the therapeutic role of bisphosphonates like zoledronic acid alongside surgical intervention to address these kinds of bony deformities and improve patient outcomes.

Osteogenesis Imperfecta: A study of the patient journey in 13 European countries

INTRODUCTION

Osteogenesis imperfecta (OI) is a heritable skeletal disorder and comprises various subtypes that differ in clinical presentation, with Type I considered the least severe and Types III/IV the most severe forms. The study aim was to understand the OI patient diagnostic and treatment journey across Europe.

METHODS

We conducted a qualitative, descriptive study to understand the OI patient journey. A selection of people with OI/their caregivers and clinicians involved in OI-patient care from across Europe were interviewed using a specially developed questionnaire.

RESULTS

Between May 2022 and July 2022, 22 people with OI/caregivers and 22 clinicians (endocrinologists, orthopaedic surgeons, geneticists and metabolic specialists) from across Europe were interviewed. Our study showed various areas of concerns for the OI community. Timely diagnosis of OI is essential; misdiagnoses and a delay to treatment initiation are all too common. There are a lack of consensus guidelines regarding optimal treatments (including when bisphosphonate therapy should be initiated and the route of administration) and patient management throughout the duration of the patient's life. Adult OI patients do not have a medical home and are often managed by endocrinologists and rheumatologists. Adult care is often reactive based on the development of new symptoms. The psychosocial burden of OI impacts on the patient's quality of life.

CONCLUSIONS

There is an urgent need for increased awareness about OI and its wide range of symptoms. In particular, there is a need for consensus guidelines outlining the optimum care throughout the duration of the OI patient's life.

Craniofacial dysmorphism of osteogenesis imperfecta mouse and effect of cathepsin K knockout: Preliminary craniometry observations

OBJECTIVES

In addition to bone fragility, patients with osteogenesis imperfecta (OI) type III have typical craniofacial abnormalities, such as a triangular face and maxillary micrognathism. However, in the osteogenesis imperfecta mouse (oim), a validated model of OI type III, few descriptions exist of craniofacial phenotype. Treatment of OI mostly consists of bisphosphonate administration. Cathepsin K inhibition has been tested as a promising therapeutic approach for osteoporosis and positive results were observed in long bones of cathepsin K knocked out oim (oim/CatK-/-). This craniometry study aimed to highlight the craniofacial characteristics of oim and Cathepsin K KO mouse.

MATERIALS AND METHODS

We analyzed the craniofacial skeleton of 51 mice distributed in 4 genotype groups: Wt (control), oim, CatK-/-, oim/CatK-/-. The mice were euthanized at 13 weeks and their heads were analyzed using densitometric (pQCT), X-ray cephalometric, and histomorphometric methods.

RESULTS

The craniofacial skeleton of the oim mouse is frailer than the Wt one, with a reduced thickness and mineral density of the cranial vault and mandibular ramus. Different cephalometric data attest a dysmorphism similar to the one observed in humans with OI type III. Those abnormalities were not improved in the oim/CatK-/- group.

CONCLUSION

These results suggest that oim mouse could serve as a complete model of the human OI type III, including the craniofacial skeleton. They also suggest that invalidation of cathepsin K has no impact on the craniofacial abnormalities of the oim model.

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.

TMEM38B Gene Mutation Associated With Osteogenesis Imperfecta

Osteogenesis imperfecta is a genetic disorder characterized by decreased bone density, bone deformities, and fractures. It results from mutations in different genes, including all steps of collagen 1 synthesis and modifications. In addition, the gene is involved in the homeostasis of intracellular calcium. TMEM38B is a gene involved in the formation of a cation channel responsible for calcium entry intracellularly. Mutations in this gene are associated with osteogenesis imperfecta. However, this mutation has not been frequently discussed in the literature. In our study, we report a case of TMEM38B-associated autosomal recessive osteogenesis imperfecta in a child of a consanguineous family presented with a history of multiple prenatal and postnatal fractures. No other associated complications are present in our case.