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46 result(s) for "Hypochondroplasia"
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Deeplasia: deep learning for bone age assessment validated on skeletal dysplasias
BackgroundSkeletal dysplasias collectively affect a large number of patients worldwide. Most of these disorders cause growth anomalies. Hence, evaluating skeletal maturity via the determination of bone age (BA) is a useful tool. Moreover, consecutive BA measurements are crucial for monitoring the growth of patients with such disorders, especially for timing hormonal treatment or orthopedic interventions. However, manual BA assessment is time-consuming and suffers from high intra- and inter-rater variability. This is further exacerbated by genetic disorders causing severe skeletal malformations. While numerous approaches to automate BA assessment have been proposed, few are validated for BA assessment on children with skeletal dysplasias.ObjectiveWe present Deeplasia, an open-source prior-free deep-learning approach designed for BA assessment specifically validated on patients with skeletal dysplasias.Materials and methodsWe trained multiple convolutional neural network models under various conditions and selected three to build a precise model ensemble. We utilized the public BA dataset from the Radiological Society of North America (RSNA) consisting of training, validation, and test subsets containing 12,611, 1,425, and 200 hand and wrist radiographs, respectively. For testing the performance of our model ensemble on dysplastic hands, we retrospectively collected 568 radiographs from 189 patients with molecularly confirmed diagnoses of seven different genetic bone disorders including achondroplasia and hypochondroplasia. A subset of the dysplastic cohort (149 images) was used to estimate the test–retest precision of our model ensemble on longitudinal data.ResultsThe mean absolute difference of Deeplasia for the RSNA test set (based on the average of six different reference ratings) and dysplastic set (based on the average of two different reference ratings) were 3.87 and 5.84 months, respectively. The test–retest precision of Deeplasia on longitudinal data (2.74 months) is estimated to be similar to a human expert.ConclusionWe demonstrated that Deeplasia is competent in assessing the age and monitoring the development of both normal and dysplastic bones.
Clinical Utility of NGS-Based Diagnosis in Primary Ciliary Dyskinesia: Experience from a Brazilian Pediatric Cohort at a Reference Center for Rare Diseases
Background: Primary ciliary dyskinesia (PCD) is a rare and genetically heterogeneous disorder that remains underdiagnosed in low- and middle-income countries, largely due to limited access to specialized diagnostic tests. Genetic analysis has become an essential component of PCD diagnosis, particularly where functional and ultrastructural evaluations are unavailable. Methods: We conducted an investigational study including children and adolescents with clinical suspicion of PCD followed at a Brazilian tertiary center. Clinical characterization included detailed phenotyping and calculation of the PICADAR score. Molecular investigation was performed using exome sequencing as a frontline diagnostic approach. Results: Among 27 individuals evaluated, 10 (37%) received a confirmed molecular diagnosis of PCD. An additional 6 (22%) individuals had inconclusive molecular findings, mainly due to variants of uncertain significance (VUS), and were classified as likely PCD based on combined clinical and molecular evidence. Higher PICADAR scores were more frequently observed among individuals with confirmed or likely molecular diagnosis, with 9 of 10 confirmed cases presenting a score above 5. Beyond PCD-associated findings, exome sequencing also enabled the identification of clinically relevant additional diagnoses, including cystic fibrosis, FGFR3-related hypochondroplasia, and ACMG-reportable secondary finding involving BRCA2. Some unresolved cases may also reflect inherent technical limitations of exome sequencing, including restricted sensitivity for copy-number variants, suboptimal coverage of highly homologous or GC-rich regions, and limited detection of deep intronic and other variants. Additional factors include challenges in variant interpretation and incomplete knowledge of disease-associated genes. Conclusions: Frontline exome sequencing is a valuable diagnostic tool for PCD, particularly when integrated with robust clinical phenotyping. Clinical scoring systems such as PICADAR may help prioritize individuals for genetic testing and optimize diagnostic yield in resource-limited settings.
Collagen X Marker Levels are Decreased in Individuals with Achondroplasia
Collagen X marker (CXM) is a degradation fragment of collagen type X. It is a real-time biomarker of height velocity with established norms. Plasma C-type natriuretic peptide (CNP) and NTproCNP levels have also been found to correlate with growth velocity in the general population and are elevated in individuals with achondroplasia compared with age- and sex-matched controls. Collagen X marker levels in people with fibroblast growth factor receptor 3 (FGFR3)-opathies have never been systematically measured. The objective of this study was to measure CXM in a population of dwarfism caused by FGFR3-opathies. Using the same cohort in which CNP and NTproCNP levels were previously measured, archived serum aliquots from 63 children with achondroplasia, six with hypochondroplasia, and two with thanatophoric dysplasia had CXM concentrations measured. Results were plotted against age- and sex-specific norms, and standard deviation scores were plotted for comparison between clinical diagnoses. CXM levels were significantly decreased (p < 0.0001) in children with achondroplasia compared with age- and sex-matched controls. Temporal patterns of change in CXM levels were sex-dependent. As the FGFR3 pathway was more constitutively active, CXM levels decreased. New tools are emerging to study impact of skeletal dysplasia on growth plate regulation and function.
Molecular Basis for Hypochondroplasia in Japan
Hypochondroplasia is an autosomal dominant genetic disorder due to a heterozygous pathogenic variant of the FGFR3 gene. The early diagnosis of hypochondroplasia is necessary, since growth hormone is effective for improving adult height. The genetic test for the FGFR3 gene could help the early diagnosis. The detailed characteristics of FGFR3 genotypes have not been widely investigated in Japan, except for a common pathogenic variant, p.Asn540Lys. This study retrospectively analyzed the FGFR3 genotypes of 35 patients from 30 families with hypochondroplasia (age, range 0–6 years, median 1 year) in Japan. The pathogenic variants of FGFR3 were identified in all the patients: p.Asn540Lys in 23 probands (76.7%), p.Lys650Gln in 2 (6.7%), p.Leu324His in 2 (6.7%), p.Leu324Val, p.Ser351Cys, and p.Lys650Thr in 1 each (3.2%). The median age at diagnosis, height SD score at diagnosis, or the severity of radiologic findings was not significantly different between probands with p.Asn540Lys and those with other variants. Intellectual disability or epilepsy was identified in seven patients with p.Asn540Lys, but none with other variants. The genetic test of FGFR3 can be useful for assessing the potential risk of neurological sequela in children with hypochondroplasia.
Achondroplasia and hypochondroplasia in France: a nationwide epidemiological analysis
Background Achondroplasia (ACH) and hypochondroplasia (HCH) are among the most common forms of skeletal dysplasia, caused by gain-of-function variants in the FGFR3 gene, leading to disproportionate short stature. The birth prevalence of HCH remains poorly defined. In addition, the reported birth prevalence of ACH in Europe and globally may not be applicable to France, given its relatively high rate of pregnancy terminations for medical reasons. This retrospective study provides the first birth prevalence estimates for ACH and HCH in France, using the French National Registry of Rare Diseases ( Banque Nationale de Données Maladies Rares , BNDMR). Results As of January 2024, 766 patients with ACH (ORPHA:15) and 408 with HCH (ORPHA:429) were identified. Most patients were diagnosed and cared for within the network of constitutional bone diseases centers (ACH: 71.3%; HCH: 63.4%). Overall, 85.5% of ACH cases and 57.2% of HCH cases were related to de novo genetic variants ( p  < 0.0001). ACH was diagnosed prenatally in 40.8% and at birth in 40.6% of patients, whereas HCH was diagnosed postnatally in 65.7% of cases ( p  < 0.0001). To estimate live birth prevalence, we focused on pediatric patients (0–15 years) born between 2008 and 2023. The mean (range) live birth prevalence was 3.27 per 100,000 for ACH (1.90–4.03) and 1.31 per 100,000 for HCH (0.54–2.08). Conclusions This study provides the first nationwide birth prevalence estimates for ACH and HCH in France, leveraging data from BNDMR. ACH is often identified prenatally, whereas HCH is predominantly diagnosed postnatally. The prevalence of HCH may be underestimated due to under-recognition of milder forms. With the emergence of specific therapies for ACH, and for HCH in the near future, strengthening specialized care pathways is critical to ensure equitable access to timely diagnosis and interventions. Clinical trial number Not applicable.
Mental health conditions, physical functioning, and health-related quality of life in adults with a skeletal dysplasia: a cross-sectional multinational study
Background This cross-sectional study investigated mental health conditions, physical functioning, and health-related quality of life (HRQOL) in adults with short-statured skeletal dysplasia conditions across three centres; in New York, Newcastle-upon-Tyne and Norway. Methods Questionnaires were sent to patients registered at the centres or distributed to adults attending clinics. The questionnaires included demographics, medical history, depression (PHQ-8), anxiety (GAD-7), pain catastrophizing, activities of daily living (HAQ), and HRQOL (SF 36/RAND-36 and PROMIS-29). Results Of the 142 participants, 62 (44%) had achondroplasia (n = 59) or hypochondroplasia (n = 3), and 80 (56%) had other skeletal dysplasia conditions (OSD), the largest groups being multiple epiphyseal dysplasia (n = 14), diastrophic dysplasia (n = 9), spondyloepiphyseal dysplasia congenita (n = 9) and pseudoachondroplasia (n = 8). Mean age was 41 (range 18–80) years. A prior psychiatric diagnosis was reported by 36%. Clinically significant symptoms of depression (PHQ-8 score ≥ 10) and anxiety (GAD-7 score ≥ 10) were reported by 23% and 13%. Almost all (99%) reported pain, while 9% had clinically significant levels of pain catastrophizing. For daily activities, the most affected domains were activities, reach and walking. The prevalence of current depression and anxiety symptoms was considerably higher in the study population than in the general US population. Participants with OSD reported more psychiatric diagnoses, depression and anxiety symptoms, more pain and challenges in performing daily activities, and lower HRQOL compared to participants with achondroplasia/hypochondroplasia. Conclusion Adults with skeletal dysplasia appear to have an increased risk for mental health issues and reduced physical functioning, which may impact HRQOL. These findings underscore the importance of including a formal assessment of mental health, pain and daily activities as part of regular medical follow-up across the lifespan in these patients.
Role of genetic investigation in the diagnosis of short stature in a cohort of Italian children
Background Short stature (SS) is defined as height more than 2 standard deviations below the mean for age and sex. Hypothyroidism, celiac disease, growth hormone deficiency, hormonal abnormalities, and genetic conditions are among its causes. A wide range of conditions often due to largely unknown genetic variants can elude conventional diagnostic workup. Aim We used next-generation sequencing (NGS) to better understand the etiology of SS in a cohort of Italian children. Patients and methods The study sample was 125 children with SS of unknown origin referred to our Institute between 2015 and 2021. All had undergone complete auxological and hormonal investigations to exclude common causes of SS. Genetic analysis was performed using a NGS panel of 104 genes. Clinical data were reviewed to clarify the pathogenicity of the variants detected. Results In this cohort, 43 potentially causing variants were identified in 38 children. A syndromic genetic condition was diagnosed in 7: Noonan syndrome in 3, Leri–Weill syndrome in 3, and hypochondroplasia in 1. Moreover, 8 benign variants and other 37 like benign variants were found. In 88 children, 179 variants of uncertain significance (VUS) were identified. No variant was found in 16 children. Conclusion Genetic analysis is a useful tool in the diagnostic workup of patients with SS, in adapting management and treatment, and in identifying syndromes with mild atypical clinical features. The role of VUS should not be underestimated, particularly when multiple VUS with possible mutual worsening effects are present in the same child.
Dental characteristics of patients with four different types of skeletal dysplasias
ObjectiveSkeletal dysplasia (SD) comprises more than 450 separate disorders. We hypothesized that their dental features would be distinctive and investigated the tooth characteristics of four patients with different SDs.Material and methodsFour SD patients with molecularly confirmed diagnoses, Pt-1 acromicric dysplasia, Pt-2 hypophosphatasia and hypochondroplasia, Pt-3 cleidocranial dysplasia, and Pt-4 achondroplasia, were recruited. A tooth from each patient was evaluated for mineral density (micro-computerized tomography), surface roughness (surface profilometer), microhardness, mineral contents (energy-dispersive X-ray), and ultrastructure (scanning electron microscopy and histology), and compared with three tooth-type matched controls.ResultsPt-1 and Pt-3 had several unerupted teeth. Pt-2 had an intact-root-exfoliated tooth at 2 years old. The lingual surfaces of the patients’ teeth were significantly smoother, while their buccal surfaces were rougher, than controls, except for Pt-1’s buccal surface. The patients’ teeth exhibited deep grooves around the enamel prisms and rough intertubular dentin. Pt-3 demonstrated a flat dentinoenamel junction and Pt-2 had an enlarged pulp, barely detectable cementum layer, and ill-defined cemento-dentinal junction. Reduced microhardnesses in enamel, dentin, and both layers were observed in Pt-3, Pt-4, and Pt-1, respectively. Pt-1 showed reduced Ca/P ratio in dentin, while both enamel and dentin of Pt-2 and Pt-3 showed reduced Ca/P ratio.ConclusionEach SD has distinctive dental characteristics with changes in surface roughness, ultrastructure, and mineral composition of dental hard tissues.Clinical relevanceIn this era of precision dentistry, identifying the specific potential dental problems for each patient with SD would help personalize dental management guidelines.