National Trends in Inpatient Hospital Outcomes of Children with Osteogenesis Imperfecta and the Importance of Extraskeletal Manifestations: A Kids' Inpatient Database Study

OBJECTIVE

To investigate the extent of extraskeletal manifestations along with inpatient outcomes and complications associated with osteogenesis imperfecta (OI).

STUDY DESIGN

This cross-sectional study utilized the Kids' Inpatient Database as a part of the Healthcare Cost and Utilization Project to investigate inpatient hospital outcomes and management in patients with OI from 1997 through 2016. Data regarding hospital characteristics, cost of treatment, inpatient outcomes, and procedures were collected and analyzed.

RESULTS

There were 7291 admissions that listed OI as a diagnosis in the Kids' Inpatient Database from 1997 through 2016. Unexpectedly, more than one-third of all admissions in these children with OI presented with an extraskeletal manifestation. The rate of major complications was 3.85%. The rate of minor complications was 19.4%, most commonly respiratory problems. The mortality rate was 18.2% in the neonatal period and 1.0% in all other admissions. Total charges of hospital stay increased over the years.

CONCLUSIONS

We identified a striking prevalence of extraskeletal manifestations in OI along with inpatient outcomes and complications associated with OI, of which respiratory complications were predominant. We observed a significant financial burden for patients with OI and identified additional risks for financial crisis, in addition to disparities in care identified among socioeconomic groups. These data contribute to a more holistic understanding of OI from diagnosis to management.

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.

Multi-gene panel sequencing in highly consanguineous families and patients with congenital forms of skeletal dysplasias

Skeletal dysplasias (SKDs) are a heterogeneous group of more than 750 genetic disorders characterized by abnormal development, growth, and maintenance of bones or cartilage in the human skeleton. SKDs are often caused by variants in early patterning genes and in many cases part of multiple malformation syndromes and occur in combination with non-skeletal phenotypes. The aim of this study was to investigate the underlying genetic cause of congenital SKDs in highly consanguineous Pakistani families, as well as in sporadic and familial SKD cases from India using multigene panel sequencing analysis. Therefore, we performed panel sequencing of 386 bone-related genes in 7 highly consanguineous families from Pakistan and 27 cases from India affected with SKDs. In the highly consanguineous families, we were able to identify the underlying genetic cause in five out of seven families, resulting in a diagnostic yield of 71%. Whereas, in the sporadic and familial SKD cases, we identified 12 causative variants, corresponding to a diagnostic yield of 44%. The genetic heterogeneity in our cohorts was very high and we were able to detect various types of variants, including missense, nonsense, and frameshift variants, across multiple genes known to cause different types of SKDs. In conclusion, panel sequencing proved to be a highly effective way to decipher the genetic basis of SKDs in highly consanguineous families as well as sporadic and or familial cases from South Asia. Furthermore, our findings expand the allelic spectrum of skeletal dysplasias.

Current situation of osteogenesis imperfecta in Spain: results from a Delphi study

BACKGROUND

Osteogenesis imperfecta (OI) is a rare disease characterized by low bone mass and bone fragility, associated with an increased risk of fractures, and skeletal and extra-skeletal symptoms that results in an impairment of health-related quality of life of OI patients. Since published studies on OI in Spain are limited, this study aimed to determine the epidemiology, assessed the disease burden, management and unmet needs of OI patients in Spain. Thirty-four experts in the management of patients with osteogenesis imperfecta completed two rounds of online consultation and reported real-life experience and data from Spanish hospitals. Delphi study questionnaires were based on literature review. A working group of nationally recognized clinical experts supported the development of the study questionnaires and the final validation of results.

RESULTS

The estimated prevalence of patients diagnosed with OI in Spain is 0.56:10,000 inhabitants (95%CI: 0.54-0.59), which represents that, approximately, 2,669 OI patients are currently managed in Spanish hospitals. It is estimated that approximately 269 new patients would be diagnosed with OI each year in Spain, representing an estimated incidence of 0.06 (95%CI: 0.05-0.06) per 10,000 inhabitants per year. Clinical management of OI in Spain is performed by a range of medical specialists; however, multidisciplinary care is not fully implemented. The absence of an approved curative treatment or a treatment to reduce the clinical features of the disease remains the main unmet need.

CONCLUSIONS

This study provides a snapshot of the current situation of patients with OI in Spain reported by clinical experts. The results provide an estimation of the epidemiology of the disease, and complement the available evidence on disease burden, clinical management, and unmet needs of these patients in Spain.

Vosoritide treatment for children with hypochondroplasia: a phase 2 trial

Background

Hypochondroplasia is a rare autosomal dominant skeletal dysplasia due to activating variants in FGFR3. It presents with disproportionate short stature with a wide range of clinical severity. There are currently no approved medications to treat short stature in children with hypochondroplasia. Vosoritide is a C-type natriuretic peptide analog that was recently approved for improving growth in children with achondroplasia. We aimed to evaluate the safety and efficacy of vosoritide in children with hypochondroplasia.

Methods

We conducted a single-arm, phase 2, open-label trial at a single centre in the USA and enrolled 26 children with hypochondroplasia. The trial consists of a 6-month observation period to establish a baseline annualized growth velocity followed by a 12-month intervention period during which vosoritide is administered daily via subcutaneous injection at a dose of 15 μg/kg/day. The trial's co-primary endpoints included the incidence of adverse events and the change from baseline in age-sex standardized annualized growth velocity and height standardized deviation score (SDS) after 12 months of treatment. This trial is registered with ClinicalTrials.gov (NCT04219007).

Findings

Twenty-four participants with a mean age of 5.86 years received vosoritide therapy. The first participant was enrolled on August 4, 2020, and the final participant completed the 18-month trial on September 8, 2023. Vosoritide was well tolerated with no treatment-related serious adverse events. Injection site reactions occurred in 83.3% of participants. No participants discontinued therapy due to an adverse event. Annualized growth velocity increased by 2.26 standard deviations (SD) and height SDS increased by 0.36 SD during the treatment period versus the observation period. Hypochondroplasia specific height SDS increased by 0.38 SD. There was a 1.81 cm/year increase in absolute annualized growth velocity.

Interpretation

Vosoritide was safe and effective in increasing growth velocity in children with hypochondroplasia. Efficacy was similar to what has been reported in children with achondroplasia.

Funding

This study was supported by an investigator-initiated grant from BioMarin Pharmaceutical.

The impact of metabolic disorders on management of periodontal health in children

Periodontitis is a chronic inflammatory disease caused by plaque biofilm which shares risk factors with systemic chronic diseases such as diabetes, cardiovascular disease, and osteoporosis. Many studies have found increased prevalence and rate of progression of periodontal disease in children with common metabolic disorders. Although the causal relationship and specific mechanism between them has not been determined yet. The aim of this paper is to progress on the impact of metabolic disorders on periodontal health in children and the underlying mechanisms, which provides new evidences for the prevention and intervention of metabolic disorders and periodontitis in children.

Case Report: A novel de novo variant of COL1A1 in fetal genetic osteogenesis imperfecta

Objective

Osteogenesis imperfecta (OI) is a rare genetic disorder. Clinical severity is heterogeneous. The purpose of this study was to investigate the genetic characteristics of a fetus with OI by whole exome sequencing (WES) and identify the cause of the disease.

Methods

In this study, a fetus with osteogenic dysplasia was referred to our hospital. DNA was extracted from the aborted fetal tissue and peripheral blood of the parents. To identify the pathogenic genes, we conducted the trio-WES using DNA. A de novo variant in the COL1A1 gene is suspected to be the cause of the OI phenotype. We used Sanger sequencing for validation and various bioinformatics methods (such as SIFT, PolyPhen2, Mutation Taster, conservative analysis, SWISS Model, glycosylation site prediction, and I-Mutant 2.0) for analysis.

Results

Both WES and Sanger sequencing identified a novel de novo variant of COL1A1 (c. 1309G>A, p. Gly437Ser) in a fetus with OI. Bioinformatic analysis showed that the affected residue, p. Gly437, was highly conserved in multiple species and predicted that the variant was deleterious and may have an impact on protein function. This variant is present in highly conserved glycine residues of Gly-X-Y sequence repeats of the triple helical region of the collagen type I α chain, which may be the cause of OI.

Conclusion

This study revealed that the c.1309G>A (p. Gly437Ser) variant in the COL1A1 gene may be the genetic cause of fetal OI in this case. The discovery of this variant enriched the variation spectrum of OI. WES improves the accurate diagnosis of fetal OI, and doctors can provide patients with appropriate genetic counseling.

Lung Hypoplasia in Fetuses with Skeletal Dysplasia Determined by Fetal Lung Weight: Which Ultrasound Measurement/Ratio Has the Highest Detection Rate

INTRODUCTION

To determine lung hypoplasia in cases with fetal skeletal dysplasia based on the total lung weight at autopsy as the most accountable surrogate marker for pulmonary hypoplasia.

METHODS

This retrospective cohort study included all pregnancies with antenatal diagnosis of skeletal dysplasia (2012-2018). We included only cases in which information on fetal biometry was available within 2 weeks before delivery and had autopsy and skeletal X-rays + molecular analysis using extracted fetal DNA. We compared the predictive accuracy of fetal sonographic body-proportional ratios (BPRs) including: (1) thoracic circumference-to-abdominal circumference ratio, (2) the femur length-to-abdominal circumference (FL/AC) ratio, (3) head circumference-to-abdominal circumference ratio, and (4) foot length-to-femur length ratio. Lung hypoplasia was defined as total lung weight below -2 SD from the expected mean for gestational age.

RESULTS

Fifty three pregnancies with antenatal diagnosis of skeletal dysplasia underwent autopsy included. Lung hypoplasia was determined in 34 (64.1%). Median of gestational age at last sonographic assessment was 21.3 (19.9-24.9) weeks. FL/AC ratio demonstrated the highest area under the curve of 0.817 (95% CI: 0.685-0.949; p < 0.0001). FL/AC ≤0.1550 demonstrated the highest detection rate of 88.2% along with the highest negative predictive value of 75%.

CONCLUSION

Using a novel, more practical approach to predict lung hypoplasia in skeletal dysplasia, fetal sonographic BPRs and, specifically, FL/AC ratio demonstrate a high detection rate of lung hypoplasia.

The burden of hospital admissions for skeletal dysplasias in Sri Lanka: a population-based study

BACKGROUND

Skeletal dysplasias are a diverse group of rare disorders in the chondro-osseous tissue that can have a significant impact on patient's functionality. The worldwide prevalence of skeletal dysplasias at birth is approximately 1:5000 births. To date, disease burden and trends of skeletal dysplasias in the Sri Lankan population have not been described in any epidemiological study. Our aim was to evaluate the burden and the current trends in hospital admissions for skeletal dysplasias in the Sri Lankan population. A retrospective evaluation of hospital admissions for skeletal dysplasia during 2017-2020 was performed using population-based data from the eIMMR database which covers government hospitals in the entire country. The trends in hospital admissions for skeletal dysplasias by calendar year, age, and types of skeletal dysplasia were described using appropriate summary statistics.

RESULTS

Respective crude admission rates of skeletal dysplasias in the years 2017, 2018, 2019 and 2020 were 5.2, 8.1, 8.0, and 6.5 per million population. A female predominance (1.4:1) was noted during the studied period. Of all reported cases the majority (n = 268; 44.2%) were children less than 4 years. Each year, 0-4 years age group represented 40-47% of the total hospital admissions. More than half of the cases were reported from Colombo (28.1%) and Kandy (25.4%) districts combined. 60% of cases were diagnosed as osteogenesis imperfecta (OI). Rising trends were observed in the hospital admissions for osteogenesis imperfecta, achondroplasia and osteopetrosis, while other skeletal dysplasia types collectively showed a relatively stable trend.

CONCLUSION

This preliminary study revealed a female predominance of skeletal dysplasias and a relatively high admission rate of osteogenesis imperfecta in the Sri Lankan population. A distinct trend was not visible in the studied years probably due to the impact on hospital services due to COVID- Pandemic. Future research on the healthcare burden on families affected by skeletal dysplasia is required to better understand the overall cost of care and identify therapies that reduce admission rates. This study highlights the value of analysing population-based data on rare diseases to improve healthcare in low-resource countries.

Co-occurrence of Spondyloepiphyseal Dysplasia and X-Linked Hypophosphatemia in a Three-Generation Chinese Family

Rare genetic skeletal disorders (GSDs) remain the major problem in orthopedics and result in significant morbidity in patients, but the causes are highly diverse. Precise molecular diagnosis will benefit management and genetic counseling. This study aims to share the diagnostic experience on a three-generation Chinese family with co-occurrence of spondyloepiphyseal dysplasia (SED) and X-linked hypophosphatemia (XLH), and evaluate the therapeutic effects of two third-generation siblings. The proband, his younger brother, and mother presented with short stature, skeletal problems, and hypophosphatemia. His father, paternal grandfather, and aunt also manifested short stature and skeletal deformities. Whole exome sequencing (WES) of proband-brother-parents initially only found the proband and his younger brother had a pathogenic c.2833G > A(p.G945S) variant in the COL2A1 gene inherited from their father. Re-analysis of WES uncovered the proband and his younger brother also harbored a pathogenic ex.12 del variant in the PHEX gene transmitted from their mother. Sanger sequencing, agarose gel electrophoresis, and quantitative polymerase chain reaction proved these results. The proband and his younger brother were confirmed to have a paternally inherited SED and a maternally inherited XLH. During a 2.8-year follow-up, these two siblings remained short stature and hypophosphatemia, but their radiographic signs and serum bone alkaline phosphatase levels were improved with treatment of oral phosphate and calcitriol. Our study presents the first report of co-occurrence of SED and XLH, shows the possibility that two different rare GSDs co-exist in a single patient, and alerts clinicians and geneticists to be cautious about this condition. Our study also suggests that next-generation sequencing has limit in detecting exon-level large deletions.

"Osteogenesis Imperfecta Patients Wish Orthopedic Surgeons Had Better Strategies to Help with…"-Results of a Patient and Parent-Oriented Survey

Osteogenesis Imperfecta (OI) is a rare genetic disorder in Type I collagen characterized by bone fractures, fragility, and deformity. Current treatments are focused on decreasing fracture rates, improving bone strength, and improving overall global function. Recent research has focused primarily on fracture fixation and outcomes of intramedullary rodding of long bones. While surgical techniques continue to evolve, recent trends in OI research are focusing on patient quality of life and patient-reported outcomes. We created a 12-question survey seeking information regarding aspects of orthopedic care that OI patients and families feel are the most pressing to improve. The survey was electronically administered, and 341 individuals participated. A total of 75% of respondents who answered the age question (254/335) were adults. Regarding surgical intervention for long bones, only 16% of respondents recall being told they could not have surgery because they were too young. Of the 16%, 37.8% were told that <5 years was too young, 13.4% <4 years was too young, and 48.8% <3 years of age was too young for surgical intervention for fractures or deformities. Nearly 22% of respondents were told that their bones were too small for intramedullary fixation. The patient and family responses help elucidate the topics requiring focus for the improvement of OI orthopedic care. Patient concerns and insights should drive the research questions we ask to advance the orthopedic care of OI patients.

Prenatal diagnosis of bone dysplasias

Bone dysplasias are individually rare but collectively common. The prenatal diagnosis of bone dysplasias, especially perinatally lethal dysplasias, is of major interest to obstetric services. The current nosology of genetic skeletal disorders addresses over 400 disorders. However, in clinical practice, we encounter only a limited number of disorders, such as FGFR3-related dysplasias, osteogenesis imperfecta, and type II collagenopathies. The recent development of non-invasive prenatal genetic testing using cell-free fetal DNA in maternal blood samples has had a major impact on the prenatal diagnosis of genetic diseases. However, imaging examinations remain critical for the final diagnosis of bone dysplasias because molecular testing only shows genetic variants, and not their pathogenicity - most variants are clinically insignificant. Bone dysplasias are typically suspected when limb shortening is identified by screening ultrasound. Further assessment can be followed by more detailed ultrasound, magnetic resonance imaging (MRI), and CT. Based on these data, rational decision-making is feasible, even when the definitive prenatal diagnosis is not feasible. Here, we highlight key images of common bone dysplasias obtained by currently available modalities.

Outcomes of Growth-friendly Instrumentation in Osteogenesis Imperfecta: A Preliminary Report

BACKGROUND

There is limited literature on the outcomes in patients with osteogenesis imperfecta (OI) undergoing growth-friendly instrumentation (GFI). The purpose of this study was to report the outcomes of GFI in patients with early-onset scoliosis (EOS) and OI. We hypothesized that similar trunk elongation could be obtained in OI patients, but with higher complication rates.

METHODS

A multicenter database was studied for patients with EOS and OI etiology who had GFI from 2005 to 2020, with a minimum 2-year follow-up. Demographic, radiographic, clinical, and patient-reported outcomes data were collected and compared with an idiopathic EOS cohort matched 2:1 for age, follow-up duration, and curve magnitude.

RESULTS

Fifteen OI patients underwent GFI at a mean age of 7.3±3.0 years, with an average follow-up of 7.3±3.9 years. OI patients had a mean preoperative coronal curve of 78.1±14.5 and achieved 35% correction after index surgery. There were no differences in major coronal curves and coronal percent correction between the OI and idiopathic groups at all time points. T1-S1 length (cm) was lower for the OI group at baseline (23.3±4.6 vs. 27.7±7.0; P =0.028) but both groups had similar growth (mm) per month (1.0±0.6 vs. 1.2±1.1; P =0.491). OI patients had a significantly increased risk of proximal anchor failure, which occurred in 8 OI patients (53%) versus 6 idiopathic patients (20%) ( P =0.039). OI patients who underwent preoperative halo-traction (N=4) had greater T1-S1 length gain (11.8±3.2 vs. 7.3±2.8; P =0.022) and greater percent major coronal curve correction (45±11 vs. 23±17; P =0.042) at final follow-up versus patients with no halo-traction (N=11). Staged foundation fusion was performed in 2 cases.

CONCLUSION

Compared with matched idiopathic EOS patients, OI patients undergoing GFI achieved similar radiographic outcomes but sustained greater rates of anchor failures, likely due to weakened bone. Preoperative halo-traction was a useful adjunct and may improve final correction. Staged foundation fusion is an idea to consider for difficult cases.

LEVEL OF EVIDENCE

Therapeutic-III.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Fetal skeletal dysplasia cohort of a single tertiary referral center in Istanbul, Turkey

We report on 314 fetal cases from 297 unrelated families with skeletal dysplasia evaluated in the postmortem period from 2000 to 2017 at a single clinical genetics center in İstanbul, Turkey. The definite diagnostic yield was 40% during the prenatal period, while it reached 74.5% when combined with postmortem clinical and radiological evaluation. Molecular analyses were performed in 25.5% (n: 76) of families, and 21 novel variants were identified. Classification according to International Skeletal Dysplasia Society-2019 revision revealed limb hypoplasia-reduction defects group (39) as the leading one, 24.5%, then followed by FGFR3 chondrodysplasias, osteogenesis imperfecta, and decreased mineralization and polydactyly-syndactyly-triphalangism groups 13.6, 11.1, and 8.9%, respectively. The inheritance pattern was autosomal recessive in 54% and autosomal dominant in 42.6% of index cases. The overall consanguinity rate of the cohort was 33%. The high prevalence of ultrarare diseases along with two or more unrelated autosomal recessive entities running in the same family was noteworthy. This study highlights the pivotal role of postmortem evaluation by an experienced clinical geneticist to achieve a high diagnostic yield in fetal skeletal dysplasia cohorts. The cohort is not only a representation of the spectrum of skeletal dysplasias in a population with a high consanguinity rate but also provides an ideal research group to work on to identify the unknowns of early fetal life.

Genetic analysis of 55 cases with fetal skeletal dysplasia

BACKGROUND

Fetal skeletal dysplasia (SD) is a common congenital disability comprising a complex group of skeletal disorders with substantial clinical and genetic heterogeneity. Many of these defects are detected prenatally using ultrasound (US). However, the diagnostic accuracy of the US is limited.

METHODS

We recruited 55 unrelated fetuses with US-detected skeletal anomalies and performed sequential tests using copy number variation sequencing, targeted skeletal gene panel sequencing, or whole exome sequencing. The detected variants were validated using Sanger sequencing or multiplex ligation-dependent probe amplification. We conducted breakpoint analysis and structural modeling of variants possibly involved in fetal SD.

RESULTS

A definitive diagnosis was achieved in 81.82% of affected fetuses (45/55). We identified chromosomal abnormalities in seven cases and 36 variants, of which 18 were novel pathogenic or likely pathogenic in 11 genes in 38 cases. De novo variants were identified in 27 cases (71.05%, 27/38), and one gonosomal mosaicism variant was found in the mother of one fetus. Our case examples demonstrated the high heterogeneity of fetal SDs and the rare fetal SD-associated challenges.

CONCLUSIONS

Careful clinical evaluation of fetuses with SD can guide appropriate molecular testing. Our study extends the SD-associated pathogenic variant spectrum and provides useful genetic counselling guidance and an accurate prenatal diagnosis strategy.

Heterozygous pathogenic variants involving CBFB cause a new skeletal disorder resembling cleidocranial dysplasia

BACKGROUND

Cleidocranial dysplasia (CCD) is a rare skeletal dysplasia with significant clinical variability. Patients with CCD typically present with delayed closure of fontanels and cranial sutures, dental anomalies, clavicular hypoplasia or aplasia and short stature. Runt-related transcription factor 2 (RUNX2) is currently the only known disease-causing gene for CCD, but several studies have suggested locus heterogeneity.

METHODS

The cohort consists of eight subjects from five unrelated families partially identified through GeneMatcher. Exome or genome sequencing was applied and in two subjects the effect of the variant was investigated at RNA level.

RESULTS

In each subject a heterozygous pathogenic variant in CBFB was detected, whereas no genomic alteration involving RUNX2 was found. Three CBFB variants (one splice site alteration, one nonsense variant, one 2 bp duplication) were shown to result in a premature stop codon. A large intragenic deletion was found to delete exon 4, without affecting CBFB expression. The effect of a second splice site variant could not be determined but most likely results in a shortened or absent protein. Affected individuals showed similarities with RUNX2-related CCD, including dental and clavicular abnormalities. Normal stature and neurocognitive problems were however distinguishing features. CBFB encodes the core-binding factor β subunit, which can interact with all RUNX proteins (RUNX1, RUNX2, RUNX3) to form heterodimeric transcription factors. This may explain the phenotypic differences between CBFB-related and RUNX2-related CCD.

CONCLUSION

We confirm the previously suggested locus heterogeneity for CCD by identifying five pathogenic variants in CBFB in a cohort of eight individuals with clinical and radiographic features reminiscent of CCD.

Metaphyseal and posterior rib fractures in osteogenesis imperfecta: Case report and review of the literature

PURPOSE

Metaphyseal corner fractures and posterior rib fractures are thought to only occur in settings of inflicted injury. We describe a case of siblings who presented with metaphyseal corner fractures and multiple posterior rib fractures who were later found to carry FKBP10 mutations, a rare cause of Osteogenesis Imperfecta (OI) known as Bruck syndrome. This clinical presentation led to a literature review examining fracture types in OI and inflicted injury.

CASES

A 15-month-old male presented with multiple healing fractures of varying ages including posterior rib and metaphyseal corner fractures with no history of significant trauma. He had joint laxity, short stature and Wormian bones. His diagnosis of Bruck Syndrome led to investigations in his sibling at birth, which demonstrated the same fracture pattern including multiple posterior rib and metaphyseal corner fractures. They both had pathogenic compound heterozygous FKBP10 variants.

LITERATURE REVIEW AND RESULTS

We performed a literature review evaluating the fracture pattern in cases investigated for inflicted injury and found to have OI. Fourteen articles reported 78 children with OI initially diagnosed as inflicted injury. Of these children, 71 (91%) were diagnosed with milder forms of OI (Sillence type I and IV). Sixty-four children (81%) had clinical signs of OI including blue sclera, dentinogenesis imperfecta, short stature, joint laxity and limb bowing. Fifteen (19%) children had fractures of high specificity for inflicted injury including metaphyseal corner fractures and posterior rib fractures and 58 (74%) had fractures of moderate specificity for inflicted injury such as bilateral fractures and fractures of different ages.

CONCLUSION

Metaphyseal corner fractures and posterior rib fractures are highly associated with inflicted injury, but they have been reported in children with OI. Bruck syndrome, a rare and severe form of OI can present with metaphyseal and posterior rib fractures, including at birth. When features of OI are present in children with metaphyseal corner fractures and/or posterior rib fractures are present, genetic testing may be warranted.

Fetal Skeletal Dysplasias: Radiologic-Pathologic Classification of 72 Cases

ObjectiveThe aim of this study was to classify the fetal skeletal dysplasias (FSD) in a series of affected fetuses based on radio-pathologic criteria. Materials and methods: We gathered clinicopathologic data of 72 cases which were diagnosed among 5995 autopsies performed over a 8-year period. Results: The prevalence of FSD was 1.2:100 autopsies. The overall sex ratio (M:F) was 1.25. Gestational age was between 17 and 24 weeks in 60% of cases. The FSD were classified into 13 distinct pathologic groups. Four major groups were identified: (1) Osteogenesis imperfecta (21 cases, 29%); (2) FGFR3 chondrodysplasia (18 cases, 25%); (3) Ciliopathies (9 cases, 12%); and (4) Sulfation disorders (7 cases, 10%). Thanatophoric dysplasia type 1 and lethal osteogenesis imperfecta were the most common skeletal dysplasias. Conclusion: Our study demonstrates the usefulness of the radio-pathologic examination in the diagnosis and accurate classification of the FSD, thus enabling better targeting of genetic counseling.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Purpose

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

Methodology

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

Results

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

Qualitative

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

Conclusion

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

Rare Findings in Cleidocranial Dysplasia Caused by RUNX Mutation

Background  Cleidocranial dysplasia (CCD, #MIM119600) is an autosomal-dominant skeletal dysplasia characterized by delayed closure of the cranial sutures, aplasia, or hypoplasia of the clavicles and dental abnormalities. These findings were accompanied by mobile and drooping shoulders, frontal and parietal bossing, hypertelorism, brachycephaly, short stature, supernumerary, and late erupting teeth. Radiographic studies can reveal involvement of multiple bones including skull, chest, pelvis, and limbs. CCD can be diagnosed with clinical and radiological evaluation and validated by molecular studies. Heterozygous loss of function RUNX2 gene, which plays an important role in osteogenesis and differentiation of precursor cells, causes CCD phenotype.

Methods  In this article, we reported five cases from three unrelated families with CCD phenotype. All exons and exonic–intronic boundary regions of RUNX2 gene from five patients were analyzed by polymerase chain reaction amplification and direct Sanger-sequencing.

Results  Our patients had classical CCD phenotype and we detected three different previously described mutations including c.1171C > T, IVS4 + 4delAAGT and c.676G > A. However, nail dysplasia has never been associated with these mutations. Our patients had varying degrees of nail dysplasia. Two of three mutations are related with Runt DNA-binding domain of RUNX2 protein in Wnt signaling and c.1171C > T had effect on proline/serine/threonine-rich (PST) domain. Recently, Wnt signaling pathway was presented as a key regulator of digit and nail differentiation. Our data suggest that RUNX2 gene may have an essential role on embryogenesis of nails, probably by protecting their integrity.

Molecular diagnosis in a cohort of 114 patients with rare skeletal dysplasias

Molecular diagnosis is important to provide accurate genetic counseling of skeletal dysplasias (SD). Although next-generation sequencing (NGS) techniques are currently the preferred methods for analyzing these conditions, some of the published results have not shown a detection rate as high as it would be expected. The present study aimed to assess the diagnostic yield of targeted NGS combined with Sanger sequencing (SS) for low-coverage exons of genes of interest and exome sequencing (ES) in a series of patients with rare SD and use two patients as an example of our strategy. This study used two different in-house panels. Of 93 variants found in 88/114 (77%) patients, 57 are novel. The pathogenic variants found in the following genes: B3GALT6, PCYT1A, INPPL1, LIFR, of four patients were only detected by SS. In conclusion, the high diagnostic yield reached in the present study can be attributed to both a good selection of patients and the utilization of the SS for the insufficiently covered regions. Additionally, the two case reports-a patient with acrodysostosis related to PRKAR1A and another with ciliopathy associated with KIAA0753, add new and relevant clinical information to the current knowledge.

Gender-Related Impact of Sclerostin Antibody on Bone in the Osteogenesis Imperfecta Mouse

Osteogenesis imperfecta (OI), which is most often due to a collagen type 1 gene mutation, is characterized by low bone density and bone fragility. In OI patients, gender-related differences were reported, but data in the literature are not convergent. We previously observed that sclerostin antibody (Scl-Ab), which stimulates osteoblast Wnt pathway via sclerostin inactivation, improved spine and long-bone parameters and biomechanical strength in female oim/oim mice, a validated model of human type 3 OI. Here, we wanted to highlight the effect of Scl-Ab on male oim/oim bones in order to identify a possible distinct therapeutic effect from that observed in females. According to the same protocol as our previous study with female mice, male wild-type (Wt) and oim/oim mice received vehicle or Scl-Ab from 5 to 14 weeks of age. Clinimetric and quantitative bone parameters were studied using X-rays, peripheral quantitative computed tomography, microradiography, and dynamic histomorphometry and compared to those of females. Contrary to Wt mice, male oim/oim had significantly lower weight, snout-sacrum length, and bone mineral content than females at 5 weeks. No significant difference in these clinimetric parameters was observed at 14 weeks, whereas male oim showed significantly more long-bone fractures than females. Scl-Ab improved bone mineral density and bone volume/total volume ratio (BV/TV) of vertebral body in Wt and oim/oim, without significant difference between male and female at 14 weeks. Male vehicle oim/oim had a significantly lower cortical thickness (Ct.Th) and BV/TV of tibial diaphysis than female and showed a higher number of fractures at 14 weeks. Scl-Ab increased midshaft periosteal apposition rate in such a way that tibial Ct.Th of male oim/oim was not significantly different from the female one at 14 weeks. The number of fractures was lower in male than female oim/oim after 14 weeks of Scl-Ab treatment, but this difference was not significant. Nevertheless, Scl-Ab-treated oim/oim male and female mice remained smaller than the Wt ones. In conclusion, our results highlighted differences between male and female oim/oim at 4 and 14 weeks of age, as well as some male-specific response of cortical bone to Scl-Ab. These gender-related particularities of oim/oim should be considered when testing experimental treatments.

Diagnostic utility of next-generation sequence genetic panel testing in children presenting with a clinically significant fracture history

We assessed the diagnostic utility of genetic panel testing to detect pathogenic variants associated with osteogenesis imperfecta in children presenting with multiple fractures. Thirty-five percent of children had a pathogenic variant. A history of a femur fracture or a first fracture occurring under 2 years of age were significant clinical predictors.

PURPOSE

The use of next-generation sequencing (NGS) genetic panels offers a comprehensive rapid diagnostic test to evaluate for pathogenic variants in the expanding list of genes associated with osteogenesis imperfecta (OI). We aimed to assess the diagnostic utility of this method in children with a clinically significant fracture history.

METHODS

NGS panel testing was performed in 87 children presenting with multiple long bone or vertebral fractures. Subjects with a known family history of OI were excluded. Associations between genetic findings and clinical characteristics were analyzed in a retrospective observational study.

RESULTS

Thirty-five percent of patients were found to have a disease-causing variant, with a higher detection rate in those patients with extra-skeletal features of OI (94 vs. 20%, p < 0.001). In subjects with extra-skeletal clinical OI features, 69% were found to have pathogenic variants in COL1A1 or COL1A2. In children without extra-skeletal features, 14 of 70 (20%) had pathogenic variants, of which 7 were variants in type 1 collagen, and the remaining 7 variants were associated with osteoblast function or signaling (PLS3, SP7, LRP5). Clinical predictors for detecting a disease-causing variant included a history of having a first fracture that occurred under 2 years of age (Odds ratio 5.5, 95%CI 1.8, 16.9) and a history of a femur fracture (Odds ratio 3.3, 95%CI 1.0, 11.1).

CONCLUSION

NGS panel testing will detect causative pathogenic variants in up to a third of children with a clinically significant fracture history, particularly where there is a history of early femur fracture.

Skeletal dysplasias in art and antiquities: A cultural journey through genes, environment, and chance

People with skeletal dysplasias have left traces in art and antiquities through ages and cultures worldwide, in Ancient Egypt, Classical Greece, Sub-Saharan Africa, Asia, and Europe. Such traces record the impact of people with skeletal dysplasia on society and culture-in daily life, religion, and mythology. However, identifying ("diagnosing") skeletal dysplasia in artifacts and interpreting what such depictions meant within the culture in which they were created is extremely challenging and at times impossible. The objectives of this short and necessarily selective survey are to present a few examples of art through different ages and cultures as a springboard for discussion not only on potential medical diagnoses but also on the lives of people with chondrodysplasia and how they were valued in the society in which they lived. The artifacts were selected from Ancient Egypt, Classical Greece, Mesoamerica (Maya), Sub-Saharan Africa (Kingdom of Benin), Tang China, and 17th Century Europe. In some cases, surviving artifacts with likely depictions of skeletal dysplasia are few and their cultural context incompletely understood. Nevertheless, certain themes and attitudes seem to repeat across different times and regions, though some cultures, such as those in Ancient Egypt, appeared to have had a comparatively positive view of people with restricted growth and chondrodysplasia.

A novel de novo mutation in COL1A1 leading to osteogenesis imperfecta confirmed by zebrafish model

Our study reports a novel dominant COL1A1 mutation in OI. Using a zebrafish model, we confirmed that the glycine to serine substitution at position 608 of the COL1A1 protein has deleterious effects on bone development.

PURPOSE

Osteogenesis imperfecta (OI), also known as brittle bone disease, is a group of genetic disorders. Mutations in two genes, collagen type I alpha 1 chain (COL1A1) and collagen type I alpha 1 chain (COL1A2), which encode the pro-a1 (I) and pro-a2 (I) chains of type I collagen, respectively, the most abundant form of collagen in the human body, cause most cases of OI.

METHODS

In this study, we used panel-based next-generation sequencing for prenatal diagnosis of a fetus whose ultrasound images suggested OI. A de novo mutation in COL1A1 gene was suspected to cause the phenotype. To validate the effect of this mutation in a zebrafish model, we constructed a plasmid containing the corresponding mutation in the zebrafish gene col1a1a (c.1744 G > A), and overexpressed the mutant protein in zebrafish larvae.

RESULTS

We identified a novel COL1A1 mutation (c.1822 G > A; p.Gly608Ser) in the fetus but not in her parents by an skeletal dysplasias panel. Bioinformatic analysis showed that the affected residue (p.Gly608) is highly conserved from zebrafish to humans. In contrast to larvae expressing wild-type (WT) col1a1a and enhanced green fluorescent protein (EGFP), col1a1a mutation-expressing larvae showed significant spinal curvature and embryonic lethality, mimicking the phenotype of human OI.

CONCLUSIONS

Our study revealed the pathogenicity of a de novo mutation, c.1822 G > A, in human COL1A1, which expands the mutation spectrum of OI.

Hospital incidence, management and direct cost of osteogenesis imperfecta in Spain: a retrospective database analysis

OBJECTIVE

The objective of this study was to analyse hospital incidence of osteogenesis imperfecta (OI) in Spanish hospitals and the associated medical costs from a healthcare system perspective.

METHODS

To this aim, a retrospective multicentre study was designed analysing admission records from patients admitted with OI in specialized care settings in Spain between 2000 and 2017. Direct medical costs were calculated based on the diagnosis-related group-based hospital payment systems, determined by the Spanish Ministry of Health.

RESULTS

Overall, 3,747 admissions were reviewed, corresponding to 998 patients, 48.20% of which were males and 51.80% females. Hospital incidence was 5.64 per 100,000 patients (95% CI, 4.80-6.60) over the study period, whereas incidence at birth was 10.14 per 100,000 (95% CI, 8.16-12.05). In-hospital mortality appeared primarily associated to neonatal conditions and acute respiratory failure. Mean length of hospital stay was 2.83 days, decreasing significantly during the study period (p < 0.0001). Readmission rate was significantly higher in younger patients (p = 0.0110). In most hospital admissions other disorders of bone and cartilage (osteoporosis and pathologic fractures) were registered, together with delayed growth and hypocalcaemia. The mean annual direct medical cost per hospital admission was €2,571, increasing significantly over the study period (p < 0.0001).

CONCLUSIONS

Overall, this study provides data that should be taken into account for the development of improved and more efficient treatment protocols, and in reducing the burden of OI at the healthcare system level.

Maternal diabetes-related malformations in Utah: A population study of birth prevalence 2001-2016

Maternal pregestational diabetes mellitus is associated with an increased risk for congenital malformations of about 2-4 times the background risk. Notably, the types and patterns of congenital malformations associated with maternal diabetes are nonrandom, with a well-established increased risk for specific classes of malformations, especially of the heart, central nervous system, and skeleton. While the increased risk in clinical and epidemiological studies is well documented in the literature, a precise estimate of overall birth prevalence of these specific congenital malformations among women with maternal pregestational diabetes, is lacking. The purpose of this study was to determine total prevalence of structural malformations associated with maternal pregestational diabetes mellitus in a population-based study. We identified infants with specific birth defects whose mother had pregestational diabetes mellitus in the Utah Birth Defect Network (UBDN), an active birth defects surveillance program that registers the occurrence of selected structural defects in the state of Utah. We defined specific maternal diabetes-related malformations based on epidemiologic and clinical studies in the literature. Of the 825,138 recorded Utah births between 2001 and 2016, a total of 91 cases were identified as likely having diabetic embryopathy within UBDN data. The prevalence of diabetes-related congenital malformation cases was calculated per year; the overall prevalence of diabetes-related malformations 2001-2016 was 1.1 per 10,000 births in Utah (95% CI, 0.9-1.3). Knowledge of the overall prevalence of diabetes-related malformations is important in predicting the number of cases that are potentially prevented with the implementation of programs to foster preconceptional management of maternal pregestational diabetes.

Birth prevalence of achondroplasia: A systematic literature review and meta-analysis

Achondroplasia is a genetic disorder that results in disproportionate short stature. The true prevalence of achondroplasia is unknown as estimates vary widely. This systematic literature review and meta‐analysis was conducted to better estimate worldwide achondroplasia birth prevalence. PubMed, Embase, Scielo, and Google Scholar were searched, complemented by manual searching, for peer‐reviewed articles published between 1950 and 2019. Eligible articles were identified by two independent researchers using predefined selection criteria. Birth prevalence estimates were extracted for analysis, and the quality of evidence was assessed. A meta‐analysis using a quality effects approach based on the inverse variance fixed effect model was conducted. The search identified 955 unique articles, of which 52 were eligible and included. Based on the meta‐analysis, the worldwide birth prevalence of achondroplasia was estimated to be 4.6 per 100,000. Substantial regional variation was observed with a considerably higher birth prevalence reported in North Africa and the Middle East compared to other regions, particularly Europe and the Americas. Higher birth prevalence was also reported in specialized care settings. Significant heterogeneity (Higgins I² of 84.3) was present and some indication of publication bias was detected, based on visual asymmetry of the Doi plot with a Furuya‐Kanamori index of 2.73. Analysis of pooled data from the current literature yields a worldwide achondroplasia birth prevalence of approximately 4.6 per 100,000, with considerable regional variation. Careful interpretation of these findings is advised as included studies are of broadly varying methodological quality.

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

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

Diagnosis and management of pediatric metabolic bone diseases associated with skeletal fragility

PURPOSE OF REVIEW

The goal of this review is to give an overview of diagnosis and up-to-date management of major pediatric metabolic bone diseases that are associated with bone fragility, including nutritional rickets, hypophosphatemic rickets, osteogenesis imperfecta, Ehlers--Danlos syndrome, Marfan's syndrome, hypophosphatasia, osteopetrosis and skeletal fluorosis.

RECENT FINDINGS

During the past decade, a number of advanced treatment options have been introduced and shown to be an effective treatment in many metabolic bone disorders, such as burosumab for hypophosphatemic rickets and asfotase alfa for hypophosphatasia. On the other hand, other disorders, such as nutritional rickets and skeletal fluorosis continue to be underrecognized in many regions of the world. Genetic disorders of collagen-elastin, such as osteogenesis imperfecta, Ehlers--Danlos syndrome and Marfan's syndrome are also associated with skeletal fragility, which can be misdiagnosed as caused by non-accidental trauma/child abuse.

SUMMARY

It is essential to provide early and accurate diagnosis and treatment for pediatric patients with metabolic bone disorders in order to maintain growth and development as well as prevent fractures and metabolic complications.

Dental and craniofacial defects in the Crtap-/- mouse model of osteogenesis imperfecta type VII

BACKGROUND

Inactivating mutations in the gene for cartilage-associated protein (CRTAP) cause osteogenesis imperfecta type VII in humans, with a phenotype that can include craniofacial defects. Dental and craniofacial manifestations have not been a focus of case reports to date. We analyzed the craniofacial and dental phenotype of Crtap^-/- mice by skull measurements, micro-computed tomography (micro-CT), histology, and immunohistochemistry.

RESULTS

Crtap^-/- mice exhibited a brachycephalic skull shape with fusion of the nasofrontal suture and facial bones, resulting in mid-face retrusion and a class III dental malocclusion. Loss of CRTAP also resulted in decreased dentin volume and decreased cellular cementum volume, though acellular cementum thickness was increased. Periodontal dysfunction was revealed by decreased alveolar bone volume and mineral density, increased periodontal ligament (PDL) space, ectopic calcification within the PDL, bone-tooth ankylosis, altered immunostaining of extracellular matrix proteins in bone and PDL, increased pSMAD5, and more numerous osteoclasts on alveolar bone surfaces.

CONCLUSIONS

Crtap^-/- mice serve as a useful model of the dental and craniofacial abnormalities seen in individuals with osteogenesis imperfecta type VII.

Prenatal diagnosis of fetal skeletal dysplasia using targeted next-generation sequencing: an analysis of 30 cases

Background

This study aims to provide genetic diagnoses for 30 cases of fetal skeletal dysplasia, and a molecular basis for the future prenatal diagnosis of fetal skeletal dysplasia.

Methods

A total of 30 cases of fetal skeletal dysplasia detected with ultrasound between January 2014 and June 2017 were analyzed. Among these fetuses, 15 fetuses had local skeletal malformations, while 15 fetuses had short limb malformations. Samples of fetal umbilical cord blood, amniotic fluid, and/or aborted tissue were collected from all cases. Karyotyping, whole genome sequencing, and targeted next-generation sequencing of skeletal disease-related pathogenic genes were performed, as needed. Blood samples were taken from the parents for verification using Sanger sequencing.

Results

Among the 30 cases of fetal skeletal dysplasia, two cases were diagnosed with trisomy 18. However, none of these cases were identified with any microdeletions or microreplications associated with skeletal dysplasia. Among the 28 chromosomally normal cases with fetal skeletal dysplasia, 21 cases were detected with mutations in genes related to skeletal diseases. Furthermore, collagen gene mutations were detected in six fetuses with short limb malformations, while heterozygous disease-causing mutations in the fibroblast growth factor receptor 3 (FGFR3) gene were detected in seven fetuses. The remaining fetuses carried mutations in other various genes, including tumor protein p63 (TP63), cholestenol delta-isomerase (EBP), cholinergic receptor nicotinic gamma subunit (CHRNG), filamin B (FLNB), and SRY-box 9 (SOX9). Three compound heterozygous mutations in CHRNG, COL11A2 and SOX9 were carried by phenotypically healthy parents.

Conclusion

Targeted next-generation sequencing can significantly improve the prenatal diagnoses of fetal skeletal dysplasia, providing parents with more precision medicine, and improved genetic counseling.

Sclerostin antibody reduces long bone fractures in the oim/oim model of osteogenesis imperfecta

Osteogenesis imperfecta type III (OI) is a serious genetic condition with poor bone quality and a high fracture rate in children. In a previous study, it was shown that a monoclonal antibody neutralizing sclerostin (Scl-Ab) increases strength and vertebral bone mass while reducing the number of axial fractures in oim/oim, a mouse model of OI type III. Here, we analyze the impact of Scl-Ab on long bones in OI mice. After 9 weeks of treatment, Scl-Ab significantly reduced long bone fractures (3.6 ± 0.3 versus 2.1 ± 0.8 per mouse, p < 0.001). In addition, the cortical thickness of the tibial midshaft was increased (+42%, p < 0.001), as well as BMD (+28%, p < 0.001), ultimate load (+86%, p < 0.05), plastic energy (+184%; p < 0.05) and stiffness (+172%; p < 0.01) in OI Scl-Ab mice compared to OI vehicle controls. Similar effects of Scl-Ab were observed in Wild type (Wt) mice. The plastic energy, which reflects the fragility of the tissue, was lower in the OI than in the Wt and significantly improved with the Scl-Ab treatment. At the tissue level by nanoindentation, Scl-Ab slightly increased the elastic modulus in bones of both OI and Wt, while moderately increasing tissue hardness (+13% compared to the vehicle; p < 0.05) in Wt bones, but not in OI bones. Although it did not change the properties of the OI bone matrix material, Scl-Ab reduced the fracture rate of the long bones by improving its bone mass, density, geometry, and biomechanical strength. These results suggest that Scl-Ab can reduce long-bone fractures in patients with OI.

Achondroplasia: a comprehensive clinical review

Achondroplasia is the most common of the skeletal dysplasias that result in marked short stature (dwarfism). Although its clinical and radiologic phenotype has been described for more than 50 years, there is still a great deal to be learned about the medical issues that arise secondary to this diagnosis, the manner in which these are best diagnosed and addressed, and whether preventive strategies can ameliorate the problems that can compromise the health and well being of affected individuals. This review provides both an updated discussion of the care needs of those with achondroplasia and an exploration of the limits of evidence that is available regarding care recommendations, controversies that are currently present, and the many areas of ignorance that remain.

Bone dysplasias in 1.6 million births in Argentina

Currently accepted birth prevalence for osteochondrodysplasias (OCDs) is about 2 per 10,000 births. Our main goal is to estimate the prevalence of OCDs in Argentina and compare it with other surveillance systems. We examined 1,663,610 births among 160 hospitals of RENAC (Red Nacional de Anomalías Congénitas - National Network of Congenital Anomalies) between November 2009 and December 2016. Cases were detected and registered according to a pre-established protocol, ranked in three diagnostic evidence levels according to available clinical documentation, and categorized according to the 9th edition of the nosology and classification of genetic skeletal disorders. Within our dataset, the most frequent groups were Group-1 (FGFR3, chondrodysplasia) and Group-25 (Osteogenesis Imperfecta and decreased bone density). Birth prevalence per 10,000 for the main OCD types, were: Achondroplasia 0.47 (95% CI: 0.38-0.59), Thanatophoric Dysplasia 0.37 (95% CI: 0.29-0.48), and the Osteogenesis Imperfecta group 0.34 (95% CI: 0.26-0.44). For total OCD, birth prevalence was 2.20 per 10.000 births (95% CI: 1.98-2.44). RENAC prevalence of total OCDs was found to be lower than that reported by the Latin-American Study of Congenital Malformations (ECLAMC) and Utah Birth Defect Network but higher than EUROCAT. Our investigation is the first study of OCD prevalence in Argentina using data from every jurisdiction of the country.

Implant therapy for a patient with osteogenesis imperfecta type I: review of literature with a case report

Bone fragility and skeletal irregularities are the characteristic features of osteogenesis imperfecta (OI). Many patients with OI have weakened maxillary and mandibular bone, leading to poor oral hygiene and subsequent loss of teeth. Improvements in implant therapy have allowed for OI patients to achieve dental restoration. However, there is limited available literature on implant therapy for patients with OI. The greatest challenge in the restoration process for OI patients in an outpatient setting is ensuring primary stability and osseointegration. Improvements in synthetic grafts improve successful implant placement and prevent predisposing patients to unnecessary procedures. This report details the successful restoration process of an OI type I patient’s maxillary arch in addition to a review of the currently available literature.

Use of flexible intramedullary nailing in combination with an external fixator for a postoperative defect and pseudarthrosis of femur in a girl with osteogenesis imperfecta type VIII: a case report

Telescopic rodding has been developed in order to obtain long-lasting osteosynthesis in the growing long bones of children with osteogenesis imperfecta (OI). The major and still unsolved drawback of any telescopic rod or nail design is a lack of rotational stability and, currently, no telescopic system allows immediate weight-bearing. When these problems are associated with insufficient longitudinal bone stability and diminished healing capacity, the result can be unfavourable causing secondary bone fragment displacement, delayed or non-union. This article presents a case report of operative treatment in a 9-year-old girl affected with OI type VIII complicated with postoperative defect and pseudarthrosis of the femur causing functional impairment with loss of walking ability. A combination of intramedullary flexible nailing and minimal external fixation was applied for treatment of femoral defect-pseudarthrosis in a girl of 9 years with OI type VIII. Intramedullary and extramedullary nails with wrapping of titanium nickel mesh subperiosteally provided osteosynthesis and deformity correction of the tibia of a small intramedullary canal diameter. Upright standing and walking with progressive weight-bearing was started 4 days after surgery. There were no septic or vascular complications nor complications related to Ilizarov fixator. Radiographs demonstrated bone union in the femur 46 days after surgery. At the follow-up visit 9 months after fixator removal, clinical alignment remained excellent without any relapse of deformity. Bone remodelling with restitution of medullary canal was noted on lower limb radiographs. The patient was able to stand and walk without pain with an aide or walker. At the follow-up visit 17 months after fixator removal, there was no decrease in achieved functional abilities and the treatment outcome remained satisfactory. Use of an external fixator with intramedullary nailing for treatment of postoperative pseudarthrosis in patient with severe OI (recessive form of OI, type VIII) provides longitudinal, rotational and angular stability. Furthermore, this approach ensured early functional activity and walking with full weight-bearing, both favourable conditions for bone tissue regeneration. The external fixator was applied for a short period and only for additional stability and not for progressive deformity correction or other manipulation. In addition, the combination of intramedullary and extramedullary nailing and subperiosteal titanium nickel mesh seems to be promising for osteosynthesis in the deformity correction of bones with small diameter in children with OI.

A novel de novo COL1A1 mutation in a Thai boy with osteogenesis imperfecta born to consanguineous parents

Osteogenesis imperfecta (OI) is genetically heterogeneous. Mutations in COL1A1 and COL1A2 are responsible for at least 90% of the cases, which are transmitted in an autosomal dominant manner or are de novo events. We identified a Thai boy with OI whose parents were first cousins. Because the proband was the product of a consanguineous marriage, we hypothesized that he might be homozygous for a mutation in a known gene causing a recessive form of OI. Using whole exome sequencing (WES), we did not find any pathogenic mutations in any known gene responsible for an autosomal recessive form of OI. Instead, we identified a COL1A1 frameshift mutation, c.1290delG (p.Gly431Valfs*110) in heterozygosis. By Sanger sequencing, the mutation was confirmed in the proband, and not detected in his parents, indicating that it was a de novo mutation. These findings had implication for genetic counseling. In conclusion, we expanded the mutational spectrum of COL1A1 and provided another example of a de novo pathogenic mutation in heterozygosis in a patient born to consanguineous parents.

Epidemiology and Prognosis of Congenital Diaphragmatic Hernia: A Population-Based Cohort Study in Utah

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a relatively frequent and severe malformation. Population-based data on clinical presentation and associated mortality are scarce. We examined a state-wide cohort of infants with a clinically validated diagnosis of CDH to assess their clinical profile, sociodemographic patterns, and infant mortality.

METHODS

We identified CDH cases from Utah's statewide population-based surveillance program among the cohort of all pregnancy outcomes (live births, stillbirths, and pregnancy terminations) delivered from 1999 to 2011. Clinical geneticists reviewed all cases and classified them based on etiology (known, unknown), and whether they were isolated, multiple (additional unrelated major malformations or unique minor malformation), or syndromic (genetic, chromosomal).

RESULTS

CDH occurred in 1 in 3156 births (227/718,990, or 3.17 per 10,000), with no time trend during the 13 years (p = 0.85). CDH was much more common in males (male to female ratio, 1.72:1; p < 0.01). Clinically, 64% of the cases were isolated, 23% were multiples, and 13% were syndromic. Most cases were live born (90%), with fewer stillbirths (7%) and pregnancy terminations (3%). Overall infant mortality was 32.5%, and varied considerably by underlying etiology (isolated 21%; multiple 44%; syndromic 82%). Prognosis was related to specific clinical findings within each etiologic group (e.g., prematurity, low Apgar score, and intrathoracic liver).

CONCLUSION

This information on specific clinical and etiologic factors associated with prognosis can help clinicians and parents in the complex discussions about care planning and management that often occur in a crisis situation, following the diagnosis of CDH, whether prior or after delivery. Birth Defects Research 109:1451-1459, 2017.© 2017 Wiley Periodicals, Inc.

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.

Etiology and clinical presentation of birth defects: population based study

Objective To assess causation and clinical presentation of major birth defects.Design Population based case cohort.Setting Cases of birth defects in children born 2005-09 to resident women, ascertained through Utah's population based surveillance system. All records underwent clinical re-review.Participants 5504 cases among 270 878 births (prevalence 2.03%), excluding mild isolated conditions (such as muscular ventricular septal defects, distal hypospadias).Main outcome measures The primary outcomes were the proportion of birth defects with a known etiology (chromosomal, genetic, human teratogen, twinning) or unknown etiology, by morphology (isolated, multiple, minors only), and by pathogenesis (sequence, developmental field defect, or known pattern of birth defects).Results Definite cause was assigned in 20.2% (n=1114) of cases: chromosomal or genetic conditions accounted for 94.4% (n=1052), teratogens for 4.1% (n=46, mostly poorly controlled pregestational diabetes), and twinning for 1.4% (n=16, conjoined or acardiac). The 79.8% (n=4390) remaining were classified as unknown etiology; of these 88.2% (n=3874) were isolated birth defects. Family history (similarly affected first degree relative) was documented in 4.8% (n=266). In this cohort, 92.1% (5067/5504) were live born infants (isolated and non-isolated birth defects): 75.3% (4147/5504) were classified as having an isolated birth defect (unknown or known etiology).Conclusions These findings underscore the gaps in our knowledge regarding the causes of birth defects. For the causes that are known, such as smoking or diabetes, assigning causation in individual cases remains challenging. Nevertheless, the ongoing impact of these exposures on fetal development highlights the urgency and benefits of population based preventive interventions. For the causes that are still unknown, better strategies are needed. These can include greater integration of the key elements of etiology, morphology, and pathogenesis into epidemiologic studies; greater collaboration between researchers (such as developmental biologists), clinicians (such as medical geneticists), and epidemiologists; and better ways to objectively measure fetal exposures (beyond maternal self reports) and closer (prenatally) to the critical period of organogenesis.

Cleidocranial dysplasia: Clinical, endocrinologic and molecular findings in 15 patients from 11 families

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder characterized by skeletal anomalies such as delayed closure of the cranial sutures, underdeveloped or absent clavicles, multiple dental abnormalities, short stature and osteoporosis. RUNX2, encoding Runt DNA-binding domain protein important in osteoblast differentiation, is the only known gene related to the disease and identified as responsible in 70% of the cases. Our clinical evaluations revealed that short stature present at a rate of 28.6%, osteoporosis at a rate of 57.1% and osteopenia at 21.4%. In this study, RUNX2 sequencing revealed nine different variations in 11 families, eight being pathogenic of which one was novel gross insertion (c.1271_1272ins20) and one other being predicted benign in frame gross deletion (c.241_258del).

Approach to the diagnosis of skeletal dysplasias: Experience at a center with limited resources

PURPOSE

A fetus with skeletal disorder poses diagnostic challenges in a resource-poor setting with limited management options. The objective of the study was to develop a step-by-step approach for the diagnosis of skeletal dysplasia in light of the limited resources available.

METHODS

An algorithmic approach was used. The assessment for lethality was the first step, followed by the evaluation for fractures. In cases without evidence of fracture, severe constriction of thorax or associated polydactyly were searched for. In cases without severe thoracic constriction, the severity of micromelia was evaluated. After delivery, fetal examination was done to ascertain the etiology.

RESULTS

During the 6-year period, 41 cases with shortened long bones were fully evaluated. Lethality was suspected in 30 cases. Fracture and beading were present in eight cases, and severe thoracic constriction with polydactyly was observed in seven cases. Mild micromelia was seen in 19 cases and severe micromelia in 7 cases. Among lethal skeletal dysplasias, thanatophoric dysplasia was most common (six cases). Among nonlethal skeletal dysplasias, achondroplasia was seen in eight cases.

CONCLUSIONS

Lethality of skeletal dysplasia could be predicted on prenatal ultrasound with 100% accuracy. The step-by-step approach was helpful to characterize skeletal dysplasias. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:529-539, 2016.

Paleodysmorphology and paleoteratology: Diagnosing and interpreting congenital conditions of the skeleton in anthropological contexts

Most congenital conditions have low prevalence, but collectively they occur in a few percent of all live births. Congenital conditions are rarely encountered in anthropological studies, not least because many of them have no obvious effect on the skeleton. Here, we discuss two groups of congenital conditions that specifically affect the skeleton, either qualitatively or quantitatively. Skeletal dysplasias (osteochondrodysplasias) interfere with the histological formation, growth and maturation of skeletal tissues leading to diminished postural length, but the building plan of the body is unaffected. Well- known skeletal dysplasias represented in the archeological record include osteogenesis imperfecta and achondroplasia. Dysostoses, in contrast, interfere with the building plan of the body, leading to e.g. missing or extraskeletal elements, but the histology of the skeletal tissues is unaffected. Dysostoses can concern the extremities (e.g., oligodactyly and polydactyly), the vertebral column (e.g., homeotic and meristic anomalies), or the craniofacial region. Conditions pertaining to the cranial sutures, i.e., craniosynostoses, can be either skeletal dysplasias or dysostoses. Congenital conditions that are not harmful to the individual are known as anatomical variations, several of which have a high and population-specific prevalence that could potentially make them useful for determining ethnic origins. In individual cases, specific congenital conditions could be determinative in establishing identity, provided that ante-mortem registration of those conditions was ensured. Clin. Anat. 29:878-891, 2016. © 2016 The Authors Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Advances in the Classification and Treatment of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a rare disorder of type 1 collagen with 13 currently identified types attributable to inherited abnormalities in type 1 collagen amount, structure, or processing. The disease is characterized by an increased susceptibility to bony fracture. In addition to the skeletal phenotype, common additional extraskeletal manifestations include blue sclerae, dentinogenesis imperfecta, vascular fragility, and hearing loss. Medical management is focused on minimizing the morbidity of fractures, pain, and bone deformities by maximizing bone health. Along with optimizing Vitamin D status and calcium intake and physical/occupational therapy, individualized surgical treatment may be indicated. Pharmacological therapy with bisphosphonate medications is now routinely utilized for moderate to severe forms and appears to have a good safety profile and bone health benefits. New therapies with other anti-resorptives as well as anabolic agents and transforming growth factor (TGF)β antibodies are in development. Other potential treatment modalities could include gene therapy or mesenchymal cell transplant. In the future, treatment choices will be further individualized in order to reduce disease morbidity and mortality.

Advanced Paternal Age and Risk of Musculoskeletal Congenital Anomalies in Offspring

OBJECTIVE

Previous research suggests that advanced paternal age increases the risk of musculoskeletal congenital anomalies (CAs) in offspring, but findings are inconsistent. This study aims to investigate the risk of musculoskeletal CAs according to paternal age at birth in an unselected population covering cohort of children.

STUDY DESIGN

A register-based prospective study of 1,605,885 children born in Denmark, 1978-2004, using information from record-linked health and administrative registers. The association between paternal age and overall musculoskeletal CAs, limb anomalies, craniosynostosis, skeletal dysplasias, syndromic musculoskeletal CAs, and other musculoskeletal CAs were investigated by multiple logistic regression analysis.

RESULTS

For overall musculoskeletal CAs, a slightly higher risk per 10-year increase in paternal age was found (odds ratio [OR] = 1.06 [95% CI: 1.01-1.11; where CI is confidence interval]). A 26% (95% CI: 2-56%) excess risk was found for fathers aged 50+ years compared to fathers aged 30-34 years. For syndromic musculoskeletal CAs, excess risks were found for fathers aged 40+ years, compared to fathers aged 30-34 years (40-44: OR = 1.38 [95% CI: 1.01-1.88], 45-49: OR = 1.45 [95% CI: 0.89-2.34], 50+: OR = 1.42 [95% CI: 0.73-2.79]). The risks in all other subgroups of musculoskeletal CAs were increased for fathers aged 50+ years.

CONCLUSIONS

A slightly higher risk for overall musculoskeletal CAs in offspring was found with increasing paternal age, mainly due to an excess risk of syndromic musculoskeletal CAs for fathers aged 40+ years. While associations between paternal age 50+ years and increased risk of all subtypes of musculoskeletal CAs were indicated, advanced paternal age likely plays a minor role in the etiology of these anomalies.