Skeletal Abnormalities Research Articles

A homozygous variant in ARHGAP39 is associated with lethal cerebellar vermis hypoplasia in a consanguineous Saudi family

Cerebellar vermis hypoplasia refers to a varying degree of incomplete development of the cerebellum and vermis. A Saudi family with four affected individuals with cerebellar vermis hypoplasia, facial dysmorphology, visual impairment, skeletal, and cardiac abnormalities was ascertained in this study. Three out of four patients could not survive longer and had died in early infancy. Genetic analysis of the youngest affected was performed by genome-wide homozygosity mapping coupled with whole exome sequencing (WES), followed by Sanger validation. Genome-wide genotyping analysis mapped the phenotype to chromosome 8q24.3. Using an autosomal recessive model, considering deleterious variants with minor allele frequency of less than 0.001 in WES data, a homozygous missense variant (NM_025251.2; ARHGAP39; c.1301G > T; p.Cys434Phe) was selected as a potential candidate for the phenotype. The variant (c.1301G > T) in the ARHGAP39 is in the region of homozygosity on chromosome 8q24.3. ARHGAP39 is a Rho GTPase-activating protein 39 and has been known to regulate apoptosis, cell migration, neurogenesis, and cerebral and hippocampal dendritic spine morphology. Mice homozygous for arhgap39 knockouts have shown premature embryonic lethality. Our findings present the first ever human phenotype associated with ARHGAP39 alteration.

A Concise Review of Marfan Syndrome with a Congenital Cardiac Surgery Focus.

Marfan syndrome is named after Antoine Marfan, who described a 5-year-old child with congenital elongation of the digits and other skeletal abnormalities in 1896. While Marfan syndrome is a systemic connective tissue disorder predominantly involving the skeletal, cardiovascular, and ocular systems, the cardiovascular system presents the most life-threatening complications. Most cardiovascular pathologies surround the left ventricular outflow tract and aorta, with aortic dissection requiring emergent surgical management to the progression of mitral regurgitation requiring elective surgery. Intensive care management, along with a tailored approach to the surgical management of a patient with Marfan syndrome, is critical to their survival. Current surgical operations for patients include aortic root surgery, valve-sparing root replacements, aortic root replacements with conduits, and mitral valve repairs. Further research is necessary to determine the molecular, endovascular, pharmaceutical, and surgical management of Marfan syndrome. This review attempts to concisely discuss the diagnosis, complications, and medical and intensive care management of Marfan syndrome while further divulging on the surgical management of those with this disease process.

Nephrocalcinosis, distal renal tubular acidosis and skeletal abnormality in two siblings with ROGDI-related Kohlschütter-Tönz syndrome.

Kohlschütter-Tönz (KTS) is a rare autosomal recessive, genetically heterogeneous disorder characterized by a triad of early-onset seizures, global developmental delay or regression, and amelogenesis imperfecta of both temporary and permanent teeth. To date, 66 cases have been reported in the literature, of which 44 with genetic confirmation. Here we report the observation of sibling pairs in a family from a small village in India who presented with nephrocalcinosis, distal renal tubular acidosis, and skeletal abnormality. Nephrocalcinosis has only been reported once before in an individual affected with KTS. Trio exome sequencing revealed a novel, homozygous, likely pathogenic variant, c.646-2_649del, in exon 9 of the ROGDI gene (NM_024589.3) in the first child. Sanger sequencing confirmed homozygosity in both children. Both parents are heterozygous carriers of the same variant. Further research needs to be done to identify the exact mechanism by which ROGDI-encoded protein deficiency leads to nephrocalcinosis and distal renal tubular acidosis.

Dental abnormalities observed in the oculo-facio-cardio-dental (OFCD) syndrome present in two Czech families bearing novel de novo BCOR pathogenic variants

BackgroundThe oculo-facio-cardio-dental syndrome (OFCD) is an ultra-rare multiple congenital anomaly. This report describes clinical findings emphasising dental phenotype in five, molecularly confirmed, female cases from two Czech families.Case presentationDental examinations were carried out. An orthopantomogram was taken in three patients, and all patients’ intraoral cavities and teeth were photographed. Exome sequencing was performed in both probands. Results were validated by Sanger DNA sequencing which was also used to follow segregation of the variants in first-degree relatives. Dental abnormalities and congenital cataracts were present in all five cases, whilst other signs were variable and included facial dysmorphism, microphthalmia, and cardiac and skeletal abnormalities. Two individuals had cleft lip and/or cleft palate. Radiculomegaly occurred in three patients with permanent teeth and was diagnosed on orthopantomograms. Two patients had agenesis of permanent teeth. Malocclusion was also present in two patients due to crowding and a Class III malocclusion and mandibular overjet. De novo novel pathogenic variants in the BCOR gene were identified; c.2382del p.(Lys795Argfs*12) and c.3914dup p.(Gln1306Alafs*20) and co-segregated with the disease in each family.ConclusionsThe OFCD syndrome has a unique dental phenotype and dentists should be aware of signs of this ultra-rare genetic disorder. All patients with congenital cataracts and dental abnormalities, including those without a family history, should be referred for genetic testing and indicated to specialised dental care.

Body composition derangements in lung cancer patients treated with first-line pembrolizumab: A multicentre observational study.

While immune checkpoint inhibitors (ICIs) are increasingly reshaping the therapeutic landscape of non-small-cell lung cancer (NSCLC), only a limited proportion of patients achieve a relevant and long-lasting benefit with these treatments, calling for the identification of clinical and, ideally modifiable, predictors of efficacy. Body composition phenotypes may reflect aspects of patients' immunology and thereby their ability to respond to ICIs. This study aims to explore the possible association between pre-treatment body composition phenotypes, tumour response, and clinical outcomes in patients receiving first-line pembrolizumab monotherapy for advanced NSCLC. A retrospective review of consecutive patients with treatment-naïve NSCLC and PD-L1 expression ≥50% undergoing pembrolizumab at three academic institutions was performed. Pre-treatment body composition parameters were measured at the third lumbar vertebra level by computed tomography, defined using pre-established cut-offs. Primary endpoint was objective response rate (ORR), secondary endpoints progression-free survival and overall survival (PFS and OS), compared through the log-rank test and the Cox proportional hazards model. Data from 134 patients (93 males [69.4%] and 41 females [30.6%]) were collected. Median age was 69years (range 36-85), with a median follow-up of 12months (range 1-131). The median body mass index (BMI) was 24.5 (IQR 21.5; 26.1) kg/m2. Overall, 59.0% and 51.5% of patients met established radiographic criteria for evidence of sarcopenia and myosteatosis, respectively, which occur across the BMI spectrum. Multivariate regression analysis, adjusted for co-morbidities, revealed that sarcopenia (aOR 5.56, 95% CI. 2.46-12.6, P<0.0001) and low intermuscular adipose tissue (IMAT) area (aOR 1.83, 95% CI. 1.22-2.83, P=0.001) were associated with a lower rate of ORR (30.4% vs. 70.5%, P<0.0001 and 30.7% vs. 73.2%, P<0.0001, respectively). Moreover, both in univariate and multivariate analysis, adjusted for co-morbidities, low performance status according to the Eastern Cooperative Oncology Group scale (ECOG PS), sarcopenia and low IMAT were significantly related to short PFS (ECOG PS: aHR 2.73, 95% CI 1.60-4.66, P<0.0001; sarcopenia: aHR 2.24, 95% CI 1.37-3.67, P=0.001; IMAT depot: aHR 2.26, 95% 1.40-3.63, P=0.002) and OS (ECOG PS: aHR 3.44, 95% CI 1.96-6.01, P<0.0001; sarcopenia: aHR 4.68, 95% CI 2.44-8.99, P<0.0001; IMAT depot: aHR 3.18, 95% 1.72-5.88, P<0.0001). Skeletal muscle abnormalities, apparently frequent in NSCLC, potentially represent intriguing predictive markers of response to ICIs and survival outcomes. Large prospective trials are needed to validate ICIs responders' clinical biomarkers.

Epigenomic and phenotypic characterization of DEGCAGS syndrome.

Developmental Delay with Gastrointestinal, Cardiovascular, Genitourinary, and Skeletal Abnormalities syndrome (DEGCAGS, MIM #619488) is caused by biallelic, loss-of-function (LoF) ZNF699 variants, and is characterized by variable neurodevelopmental disability, discordant organ anomalies among full siblings and infant mortality. ZNF699 encodes a KRAB zinc finger protein of unknown function. We aimed to investigate the genotype-phenotype spectrum of DEGCAGS and the possibility of a diagnostic DNA methylation episignature, to facilitate the diagnosis of a highly variable condition lacking pathognomonic clinical findings. We collected data on 30 affected individuals (12 new). GestaltMatcher analyzed fifty-three facial photographs from five individuals. In nine individuals, methylation profiling of blood-DNA was performed, and a classification model was constructed to differentiate DEGCAGS from controls. We expand the ZNF699-related molecular spectrum and show that biallelic, LoF, ZNF699 variants cause unique clinical findings with age-related presentation and a similar facial gestalt. We also identified a robust episignature for DEGCAGS syndrome. DEGCAGS syndrome is a clinically variable recessive syndrome even among siblings with a distinct methylation episignature which can be used as a screening, diagnostic and classification tool for ZNF699 variants. Analysis of differentially methylated regions suggested an effect on genes potentially implicated in the syndrome's pathogenesis.

A monoallelic variant in CCN2 causes an autosomal dominant spondyloepimetaphyseal dysplasia with low bone mass

Cellular communication network factor 2 (CCN2) is a secreted extracellular matrix-associated protein, and its aberrantly increased expression has been implicated in a diversity of diseases involving pathological processes of fibrosis, chronic inflammation, or tissue injury, which has promoted the evaluation of CCN2 as therapeutic targets for multiple disorders. However, human phenotypes associated with CCN2 deficiency have remained enigmatic; variants in CCN2 have not yet been associated with a human phenotype. Here, we collected families diagnosed with spondyloepimetaphyseal dysplasia (SEMD), and screened candidate pathogenic genes for families without known genetic causes using next-generation sequencing. We identified a monoallelic variant in signal peptide of CCN2 (NM_001901.2: c.65 G > C [p.Arg22Pro]) as the cause of SEMD in 14 subjects presenting with different degree of short stature, premature osteoarthritis, and osteoporosis. Affected subjects showed decreased serum CCN2 levels. Cell lines harboring the variant displayed decreased amount of CCN2 proteins in culture medium and an increased intracellular retention, indicating impaired protein secretion. And the variant weakened the stimulation effect of CCN2 on osteogenesis of bone marrow mesenchymal stem cells. Zebrafish ccn2a knockout model and osteoblast lineage-specific Ccn2-deficient mice (Ccn2fl/fl;Prx1Cre) partially recapitulated the phenotypes including low bone mass observed in affected subjects. Pathological mechanism implicated in the skeletal abnormality in Ccn2fl/fl;Prx1Cre mice involved decreased bone formation, increased bone resorption, and abnormal growth plate formation. Collectively, our study indicate that monoallelic variants in CCN2 lead to a human inherited skeletal dysplasia, and highlight the critical role of CCN2 in osteogenesis in human.

Hyperphosphatemic Familial Tumoral Calcinosis (HFTC) in a One-Year-Old Child: A Case Report and Literature Review

Introduction: Hyperphosphatemic Familial Tumoral Calcinosis (HFTC) is a rare autosomal recessive metabolic disorder characterized by abnormal phosphate regulation and soft tissue calcifications. Early diagnosis is crucial for optimal management to prevent complications. Case Presentation: A one-year-old child presented with intermittent fevers and a gluteal mass. Ultrasound revealed a calcified abscess, and biopsy confirmed a pseudocyst. Further workup identified elevated blood calcium, phosphorus, and neutropenia. The patient was ultimately diagnosed with HFTC. Discussion: Early diagnosis of HFTC is challenging due to the rarity of the disease and the potential for non-specific initial symptoms. This case highlights the importance of considering HFTC in the differential diagnosis for a young child with unexplained soft tissue masses or skeletal abnormalities, even outside the usual age range. Conclusions: This case report emphasizes the need for a high index of suspicion for HFTC in pediatric patients with suggestive clinical features, regardless of age. Early diagnosis and prompt intervention are essential to improve long-term outcomes and prevent complications.

The Role of Cystic Fibrosis Transmembrane Conductance Regulator in Skeletal Muscle Contractile Function

Purpose: Genetic mutations in cystic fibrosis (CF) result in CF transmembrane conductance regulator (CFTR) dysfunction. CFTR is expressed in human skeletal muscle; its effect on skeletal muscle abnormalities is unknown. The study objective is to investigate the role of CFTR in skeletal muscle contractile function. Methods: We conducted a prospective, cross-sectional study comparing 34 adults with minimal and 18 with residual function CFTR mutations, recruited from Toronto Adult CF Centre, St. Michael's Hospital, Unity Health Toronto. Quadriceps, biceps brachii, and handgrip strength was measured with dynamometers; leg muscle power with the stair climb power test. Quadriceps muscle contractility was determined by quadriceps muscle strength normalized to quadriceps muscle size, measured with ultrasound images. Multivariable regression was used for analysis. Results: People with residual function CFTR mutations had higher quadriceps muscle torque normalized to quadriceps layer thickness and to rectus femoris cross-sectional area by 27.5 Nm/cm [95% CI (2.2, 52.8) Nm/cm, P = .034] and 5.6 Nm/cm2 [95% CI (0.3, 10.9) Nm/cm2, P = .041], respectively, compared with those with minimal function CFTR mutations. There were no differences in quadriceps muscle torque (P = .58), leg muscle power (P = .47), biceps brachii muscle force (P = .14), or handgrip force (P = .12) between the 2 mutation groups. Conclusions: CFTR protein may play a role in muscle contractility, implying a limited capacity to exert muscle force per unit of muscle size in people with CF. This suggests that building a greater muscle mass through resistance exercises focusing on muscle hypertrophy in exercise prescription may improve muscle strength in people with CF.

5118 When Thyroid Gland Is Not Made Of Thyroid Cells

Abstract Disclosure: A. Bulut: None. L. Ma: None. J.P. Noordzij: None. S.Y. Lee: None. Introduction: Neurofibroma is a type of peripheral nerve tumor that can arise sporadically or be a part of neurofibromatosis type 1 (NF1), a rare genetic disorder. Neurofibromas within the thyroid gland are extremely rare. Here, we present the fifth reported case of primary neurofibroma of thyroid gland. Case: A 60-year-old woman with history of systemic lupus erythematosus and hypertension presented with enlargement of left thyroid gland. She was diagnosed with Graves’ disease 40 years ago, which was treated with right thyroid lobectomy one year after the initial diagnosis. Five years after the surgery, she had recurrence of her symptoms and received radioactive iodine ablation with subsequent hypothyroidism. On presentation to endocrine clinic, she had thyroid ultrasound (US), which showed surgically absent right thyroid lobe and enlarged heterogenous left thyroid lobe measuring 5.1 cm x 3.8 cm x 3.9 cm with scant blood flow without discrete nodules. In interim, patient developed dysphagia and globus sensation. Repeat thyroid US showed enlargement of left lobe to 5.6 cm x 3.7 cm x 4.7 cm. Patient underwent completion thyroidectomy. Surgical pathology showed neurofibroma (S-100+, CD34+ and MSA-) without any thyroid parenchyma. Whole-body scan revealed no other evidence of tumors. Patient was referred for genetic analysis. Discussion: Neurofibromas are benign peripheral nerve system tumors primarily consist of Schwann cells along with other components of perineurium. They can occur as a sporadic lesion which accounts for 90% of solitary neurofibroma cases or be a part of NF1 on rare occasions. NF1 is an autosomal dominant genetic disorder due to germline mutation in NF1 gene located on chromosome 17q11.2, whose manifestations include café-au-lait macules, Lisch nodules, skeletal abnormalities, neurological deficits, and other benign and malignant tumors. Neurofibromas are the hallmarks of NF1. There are only few cases in the literature reported neurofibromas adjacent to or originating from thyroid gland. To the best of our knowledge, there have been only four other cases reporting primary neurofibroma of thyroid gland, one of which developed from thyroid capsule. Our patient most likely has primary neurofibroma of thyroid gland given the lack of syndromic features, however, genetic testing is needed in order to rule out NF1. In conclusion, clinicians should consider neurofibroma in their differential in cases of enlarging thyroid gland or nodules, especially in the presence of other clinical features. Presentation: 6/1/2024

6714 Bone And Radiologic Findings In Congenital Generalized Lipodystrophy: A Systematic Review

Abstract Disclosure: R.M. Tuska: None. M. Brush: None. A.A. Livinski: None. R.J. Brown: None. Congenital Generalized Lipodystrophy (CGL) is characterized by a near-total loss of subcutaneous adipose tissue, leading to severe metabolic and systemic comorbidities. CGL is most commonly caused by mutations in AGPAT2 (CGL1) and BSCL2 (CGL2) genes. Skeletal abnormalities such as diffuse sclerosis, lytic bone lesions, and high bone mineral density (BMD) have been recognized in many patients with CGL, but the radiologic and clinical features of these bone phenotypes remain ill-defined. The aim of this systematic review was to evaluate the bone manifestations and radiologic findings associated with CGL1 and CGL2. We searched 6 databases: CINAHL Plus, Embase, Global Index Medicus (WHO), PubMed, Scopus, and Web of Science: Core. We screened articles utilizing a dual reviewer process in Covidence. Included publications reported primary bone and radiologic findings in patients with CGL1 or CGL2. Exclusions comprised publications without full text, duplicate publications, those lacking bone measures, and review articles. Two reviewers extracted data using RedCap and assessed risk of bias. 270 records were screened and 37 records reporting 179 cases of CGL were included for data extraction. Among the 79 patients assessed for bone cysts, 49 (62%) exhibited lytic appearing lesions. Of these 49, 14 (29%) patients presented with symptomatic lesions, primarily manifesting as bone pain at the lesion site (n=6), or pathologic fracture at the lesion site (n=9). Bone biopsy (n=7) revealed thin trabeculae and extensive vascular proliferation at the lesion site. Bone marrow biopsies (n=2) and imaging (n=20) revealed normal hematopoietic marrow with a marked reduction in marrow fat. 12 patients underwent serial bone imaging revealing diffuse osteosclerosis and the absence of lytic lesions in early childhood. During adolescence, lytic lesions appeared and progressed throughout the proximal and distal ends of the long bones in the appendicular skeleton sparing the axial skeleton. Markers of bone turnover were within normal limits except for sclerostin, which was elevated in a cohort of 11 patients. High BMD (n= 65), advanced skeletal maturation (n= 49), diffuse osteosclerosis (n=30), scoliosis (n=8), pseudo-osteopoikilosis (n=6), coxa valga (n=5), enlarged epiphyses (n=7), and coarse trabeculae (n=8) were also reported. While leptin replacement therapy improved metabolic parameters in many patients, it did not reverse the high bone mineral density or significantly alter markers of bone turnover. Individuals with CGL exhibit a spectrum of skeletal abnormalities including lytic-appearing lesions, osteosclerosis, high bone mineral density, advanced skeletal maturation, and pseudo-osteopoikilosis. Further long-term follow-up is needed to comprehensively assess the progression of these lesions over the life course and to elucidate the mechanisms contributing to their development. Presentation: 6/2/2024

5118 When Thyroid Gland is Not Made of Thyroid Cells

Abstract Disclosure: A. Bulut: None. L. Ma: None. J.P. Noordzij: None. S.Y. Lee: None. Introduction: Neurofibroma is a type of peripheral nerve tumor that can arise sporadically or be a part of neurofibromatosis type 1 (NF1), a rare genetic disorder. Neurofibromas within the thyroid gland are extremely rare. Here, we present the fifth reported case of primary neurofibroma of thyroid gland. Case: A 60-year-old woman with history of systemic lupus erythematosus and hypertension presented with enlargement of left thyroid gland. She was diagnosed with Graves’ disease 40 years ago, which was treated with right thyroid lobectomy one year after the initial diagnosis. Five years after the surgery, she had recurrence of her symptoms and received radioactive iodine ablation with subsequent hypothyroidism. On presentation to endocrine clinic, she had thyroid ultrasound (US), which showed surgically absent right thyroid lobe and enlarged heterogenous left thyroid lobe measuring 5.1 cm x 3.8 cm x 3.9 cm with scant blood flow without discrete nodules. In interim, patient developed dysphagia and globus sensation. Repeat thyroid US showed enlargement of left lobe to 5.6 cm x 3.7 cm x 4.7 cm. Patient underwent completion thyroidectomy. Surgical pathology showed neurofibroma (S-100+, CD34+ and MSA-) without any thyroid parenchyma. Whole-body scan revealed no other evidence of tumors. Patient was referred for genetic analysis. Discussion: Neurofibromas are benign peripheral nerve system tumors primarily consist of Schwann cells along with other components of perineurium. They can occur as a sporadic lesion which accounts for 90% of solitary neurofibroma cases or be a part of NF1 on rare occasions. NF1 is an autosomal dominant genetic disorder due to germline mutation in NF1 gene located on chromosome 17q11.2, whose manifestations include café-au-lait macules, Lisch nodules, skeletal abnormalities, neurological deficits, and other benign and malignant tumors. Neurofibromas are the hallmarks of NF1. There are only few cases in the literature reported neurofibromas adjacent to or originating from thyroid gland. To the best of our knowledge, there have been only four other cases reporting primary neurofibroma of thyroid gland, one of which developed from thyroid capsule. Our patient most likely has primary neurofibroma of thyroid gland given the lack of syndromic features, however, genetic testing is needed in order to rule out NF1. In conclusion, clinicians should consider neurofibroma in their differential in cases of enlarging thyroid gland or nodules, especially in the presence of other clinical features. Presentation: 6/1/2024

Calvarial Thickening in Tuberous Sclerosis Complex

IntroductionTuberous sclerosis complex (TSC)-related skeletal abnormalities are under-studied. Awareness of skull thickening in TSC patient is important from the surgical standpoint because thick skull might complicate craniotomy. This study, aimed at revealing if TSC patients are generally prone to skull thickening, had led us to retrospectively investigate the frequency and characteristics of skull thickening in these patients. MethodTSC patients aged 10 to 60 years who underwent MRI were identified from the neurosurgery, dermatology or pediatrics clinic between 2010 and 2021. Two control groups were used for comparison: one with unruptured intracranial aneurysms to serve as control without anti-seizure medications (ASMs) exposure and another with non-TSC epilepsy as control with ASM exposure. Thickness of frontal, parietal, temporal, and occipital bones was measured at a fixed location of each bone across patients on T2-weighted axial images. Result29 patients fulfilled the inclusion criteria. Frontal and temporal bones of the TSC group were significantly thicker than those of either control group. Skull thickening was significantly associated with intracerebral calcification, but not with age, sex, or ASM exposure. Focal skull thickening was associated with the presence of a subcortical calcification. ConclusionsTSC patients have thickened skull that is often linked to intracerebral calcification. The presence of skull thickening may require modification of surgical approach during craniotomy. Skull thickening and the underlying intracerebral calcification likely share a common precipitating factor given their relationship. Future studies are warranted to clarify the genetic underpinnings of this relationship and even broader skeletal abnormalities in TSC.

An innovative CRISPR/Cas9 mouse model of human isolated microtia indicates the potential contribution of CNVs near HMX1 gene

BackgroundMicrotia is a prevalent congenital malformation, the precise etiology and pathogenesis of which remain elusive. Mutations in the non-coding region of the HMX1 gene have been implicated in isolated cases of microtia, emerging as a significant focus of contemporary research. Several pathogenic copy number variations (CNVs) proximal to the HMX1 gene have been documented in wild animal populations, whereas only a single large segmental duplication in this region has been identified in humans. However, the absence of a gene-edited animal model has impeded the investigation of the unclear gene function associated with HMX1 mutations in human isolated microtia. In this study, we sought to precisely identify the pathogenic mutation by analyzing three pedigrees alongside population controls. Subsequently, our objective was to develop a CRISPR/Cas9 gene-edited mouse model to elucidate the functional implications of the identified mutation. MethodsGenomic DNA was collected from 32 affected individuals across three pedigrees, as well as from 2,000 control subjects. Comprehensive genomic analyses, including genome-wide linkage analysis, targeted capture, second-generation sequencing, and copy number analysis, were conducted to identify potential mutations associated with congenital auricle malformation. CRISPR/Cas9 gene-edited murine models were generated in response to the identified mutation. The auricular phenotypes of these gene-edited mice were systematically monitored. Small-animal Micro-CT scanning was employed to identify potential craniofacial or skeletal abnormalities. Furthermore, the expression of the HMX1 gene in the PA2 region of mouse embryos was quantified using RT-qPCR. ResultsA co-segregated 600 base pair duplication located on chromosome 4 (chr4:8701900-8702500, hg19) was identified in affected individuals across three pedigrees, but was absent in healthy controls. Two types of CRISPR/Cas9 gene-edited mice were subsequently generated. The knock-in (KI) mouse model was engineered by inserting one copy of the duplicated sequence directly adjacent to the mutated site, whereas the knockout (KO) mouse model was created by excising the mutation sequence. The phenotypes of different group of CRISPR/Cas9 gene-edited mice demonstrated distinct auricular deformities. Furthermore, an increase in the copy number of the mutated sequence was associated with elevated expression levels of HMX1 in the gene-edited mouse model. ConclusionsIn this study, we further narrowed down and identified a 600 base pair copy number variation (CNV) located at chr4:8701900-8702500 (hg19), which is implicated in human bilateral, isolated microtia. Utilizing CRISPR/Cas9 technology, we developed novel mouse models harboring the identified mutation. These models serve as a robust platform for the comprehensive investigation of the underlying mechanisms of the disease.

Mechanisms of Germline Stem Cell Competition across Species.

In this review, we introduce the concept of cell competition, which occurs between heterogeneous neighboring cell populations. Cells with higher relative fitness become "winners" that outcompete cells of lower relative fitness ("losers"). We discuss the idea of super-competitors, mutant cells that expand at the expense of wild-type cells. Work on adult stem cells (ASCs) has revealed principles of neutral competition, wherein ASCs can be stochastically lost and replaced, and of biased competition, in which a winning ASC with a competitive advantage replaces its neighbors. Germline stem cells (GSCs) are ASCs that are uniquely endowed with the ability to produce gametes and, therefore, impact the next generation. Mechanisms of GSC competition have been elucidated by studies in Drosophila gonads, tunicates, and the mammalian testis. Competition between ASCs is thought to underlie various forms of cancer, including spermatocytic tumors in the human testis. Paternal age effect (PAE) disorders are caused by de novo mutations in human GSCs that increase their competitive ability and make them more likely to be inherited, leading to skeletal and craniofacial abnormalities in offspring. Given its widespread effects on human health, it is important to study GSC competition to elucidate how cells can become winners or losers.

Prevalence and typology of skeletal abnormalities in fishes of the Eastern Mediterranean.

Prevalence and typology of skeletal abnormalities in fishes of the Eastern Mediterranean.

The Role of Plain Radiography in Assessing Aborted Foetal Musculoskeletal Anomalies in Everyday Practice.

Conventional radiography is widely used for postmortem foetal imaging, but its role in diagnosing congenital anomalies is debated. This study aimed to assess the effectiveness of X-rays in detecting skeletal abnormalities and guiding genetic analysis and counselling. This is a retrospective analysis of all post-abortion diagnostic imaging studies conducted at a centre serving a population of over 300,000 inhabitants from 2008 to 2023. The data were analysed using descriptive statistics. X-rays of 81 aborted foetuses (total of 308 projections; mean: 3.8 projections/examination; SD: 1.79) were included. We detected 137 skeletal anomalies. In seven cases (12.7%), skeletal anomalies identified through radiology were missed by prenatal sonography. The autopsy confirmed radiological data in all cases except for two radiological false positives. Additionally, radiology failed to identify a case of syndactyly, which was revealed by anatomopathology. X-ray is crucial for accurately classifying skeletal abnormalities, determining the causes of spontaneous abortion, and guiding the request for genetic counselling. Formal training for both technicians and radiologists, as well as multidisciplinary teamwork, is necessary to perform X-ray examinations on aborted foetuses and interpret the results effectively.

Inactivation of spermine synthase in mice causes osteopenia due to reduced osteoblast activity.

Spermine synthase, encoded by the SMS gene, is involved in polyamine metabolism, as it is required for the synthesis of spermine from its precursor molecule spermidine. Pathogenic variants of SMS are known to cause Snyder-Robinson syndrome (SRS), an X-linked recessive disorder causing various symptoms, including intellectual disability, muscular hypotonia, infertility, but also skeletal abnormalities, such as facial dysmorphisms and osteoporosis. Since the impact of a murine SMS deficiency has so far only been analysed in Gy mice, where a large genomic deletion also includes the neighbouring Phex gene, there is only limited knowledge about the potential role of SMS in bone cell regulation. In the present manuscript we describe two patients carrying distinct SMS variants, both diagnosed with osteoporosis. Whereas the first patient displayed all characteristic hallmarks of SRS, the second patient was initially diagnosed, based on laboratory findings, as a case of adult-onset hypophosphatasia. In order to study the impact of SMS inactivation on bone remodelling we took advantage of a newly developed mouse model carrying a pathogenic SMS variant (p.G56S). Compared to their wildtype littermates 12-week-old male SmsG56S/0 mice displayed reduced trabecular bone mass and cortical thickness, as assessed by μCT analysis of the femur. This phenotype was histologically confirmed by the analysis of spine and tibia sections, where we also observed a moderate enrichment of non-mineralized osteoid in SmsG56S/0 mice. Cellular and dynamic histomorphometry further identified a reduced bone formation rate as a main cause of the low bone mass phenotype. Likewise, primary bone marrow cells from SmsG56S/0 mice displayed reduced capacity to form a mineralized matrix ex vivo, thereby suggesting a cell-autonomous mechanism. Taken together, our data identify SMS as an enzyme with physiological relevance for osteoblast activity, thereby demonstrating an important role of polyamine metabolism in the control of bone remodeling.

Microwave cavity antenna for automatic detection of chicken breast muscles affected by wooden breast defect

Over the past years, artificial selection for meat-type (broiler) chickens has resulted in improved production efficiency, but also in an increased incidence of skeletal muscle abnormalities. In particular, wooden breast (WB) abnormality causes abrupt changes in meat quality and enormous economic losses. Thus, the poultry processing industry requires a reliable method to detect the abnormality in production lines in a non-destructive and contactless way. The present research aimed to evaluate the effect of WB on dielectric properties to develop a potential online technique to distinguish unaffected from affected breasts. Sixty-five pectoralis major muscles were picked 3 h post-mortem from the same flock (42-day-old broilers, 2.8 kg average live weight) and classified by visual inspection according to their phenotype as normal (N, not showing not any signs of the WB condition; n = 33) or WB (exhibiting extensive hardened areas and stiffness perceived by manual palpation throughout the entire fillet; n = 32). WB muscles exhibited remarkably higher values of dielectric constant and loss factor in a wide range of the explored frequencies (200 MHz–14 GHz), suggesting higher water mobility and a higher solvate capacity; this makes the electromagnetic technique for classification promising. Based on the above evidence, a rapid microwave electric technique in the range 1.5 GHz–3 GHz was developed for the online detection of WB. Indeed, combining the use of a cavity antenna (vector network analyzer instrumental chain with partial least square – discriminant analysis), this technique correctly classified 100% of the validation test set.

Evaluation of the effect of tartrazine on the offspring rats in an in vivo experimental model

AbstractTartrazine, an azo dye prevalent in pharmaceuticals and food items, was investigated for its impact on fetal development, specifically examining visceral and skeletal abnormalities in rat offspring exposed to daily oral doses throughout pregnancy. Fourteen pregnant rats were randomly assigned to control and tartrazine groups (seven animals each), with tartrazine administered via oral gavage at 7.5 mg/kg throughout gestation. Offspring were categorized by gender for histopathological and genetic analysis of visceral structures. Bone quality and fracture resistance assessments involved micro‐CT, Raman spectroscopy, and biomechanical testing. Results highlighted distinct internal organ tissue differences in the tartrazine group, notably increased hemorrhagic and inflammatory cell infiltration, degeneration, and vacuolization compared to controls. Gender‐specific alterations in mRNA levels of IL‐6, IL‐1β, TNF‐α, and TRPM2 genes (p &lt; .001) were also noted. Moreover, tartrazine‐exposed groups exhibited reduced trabecular thickness, bone volume, and significant alterations in bone matrix composition and quality alongside significant decreases in fracture resistance (p &lt; 0.05). This study concludes that intrauterine exposure to tartrazine can result in adverse impacts on organ and bone development in rat offspring.