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Cohesins promote proper chromosome segregation, gene transcription, genomic architecture, DNA condensation, and DNA damage repair. Mutations in either cohesin subunits or regulatory genes can give rise to severe developmental abnormalities (such as Robert Syndrome and Cornelia de Lange Syndrome) and also are highly correlated with cancer. Despite this, little is known about cohesin regulation. Eco1 (ESCO2/EFO2 in humans) and Rad61 (WAPL in humans) represent two such regulators but perform opposing roles. Eco1 acetylation of cohesin during S phase, for instance, stabilizes cohesin-DNA binding to promote sister chromatid cohesion. On the other hand, Rad61 promotes the dissociation of cohesin from DNA. While Eco1 is essential, ECO1 and RAD61 co-deletion results in yeast cell viability, but only within a limited temperature range. Here, we report that eco1 rad61 cell lethality is due to reduced levels of the cohesin subunit Mcd1. Results from a suppressor screen further reveals that FDO1 deletion rescues the temperature sensitive (ts) growth defects exhibited by eco1 rad61 double mutant cells by increasing Mcd1 levels. Regulation of MCD1 expression, however, appears more complex. Elevated expression of MBP1, which encodes a subunit of the MBF transcription complex, also rescues eco1 rad61 cell growth defects. Elevated expression of SWI6, however, which encodes the Mbp1-binding partner of MBF, exacerbates eco1 rad61 cell growth and also abrogates the Mpb1-dependent rescue. Finally, we identify two additional transcription factors, Fkh1 and Fkh2, that impact MCD1 expression. In combination, these findings provide new insights into the nuanced and multi-faceted transcriptional pathways that impact MCD1 expression.
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Ventricular septal defects (VSDs) are recognized as one of the commonest congenital heart diseases (CHD), accounting for up to 40% of all cardiac malformations, and occur as isolated CHDs as well as together with other cardiac and extracardiac congenital malformations in individual patients and families. The genetic etiology of VSD is complex and extraordinarily heterogeneous. Chromosomal abnormalities such as aneuploidy and structural variations as well as rare point mutations in various genes have been reported to be associated with this cardiac defect. This includes both well-defined syndromes with known genetic cause (e.g., DiGeorge syndrome and Holt-Oram syndrome) and so far undefined syndromic forms characterized by unspecific symptoms. Mutations in genes encoding cardiac transcription factors (e.g., NKX2-5 and GATA4) and signaling molecules (e.g., CFC1) have been most frequently found in VSD cases. Moreover, new high-resolution methods such as comparative genomic hybridization enabled the discovery of a high number of different copy number variations, leading to gain or loss of chromosomal regions often containing multiple genes, in patients with VSD. In this chapter, we will describe the broad genetic heterogeneity observed in VSD patients considering recent advances in this field.
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Defectos del Tabique Interventricular , Humanos , Aberraciones Cromosómicas , Variaciones en el Número de Copia de ADN/genética , Predisposición Genética a la Enfermedad/genética , Defectos del Tabique Interventricular/genética , Mutación , Factores de Transcripción/genéticaRESUMEN
Cornelia de Lange syndrome (CdLS) is a rare neurodevelopmental disorder characterized by distinct dysmorphic facies, skeletal anomalies, and failure to thrive. CdLS type 5 (CdLS5) is caused by the HDAC8 gene mutations on chromosome Xq13.1 with X-linked dominant inheritance. We report our observation of an individual with CdLS5 with de novo missense mutation presenting with a novel phenotype of generalized dystonia. A four-month-old girl, second born to a non-consanguineous couple, presented with developmental delay, failure to thrive, and spastic quadriparesis. She had a history of intrauterine growth retardation in the third trimester of pregnancy. Facial gestalt was suggestive of CdLS. She had marked axial and appendicular dystonia. A skeletal survey and magnetic resonance imaging (MRI) with magnetic resonance spectroscopy (MRS) brain studies were normal. Genetic testing revealed a heterozygous missense variation c.628G>C in the HDAC8 gene. She was treated with trihexyphenidyl and clonazepam, followed by syndopa. On follow-up assessment at 22 months of age, the dystonia gradually improved but not entirely over time with medication. It is already known that single gene disorders, including SCN1A, SCN2A, KCNQ2, PRRT2, and pyridoxine deficiency, can result in isolated dystonia; we add CdLS5 (HDAC8 variation) to this expanding spectrum.
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BACKGROUND: Cornelia de Lange syndrome (CdLS) is a rare polymalformative genetic disorder with multisystemic involvement. Despite numerous clinical and molecular studies, the specific evaluation of the quality of life (QoL) and its relationship with syndrome-specific risk factors has not been explored. METHODS: The QoL of 33 individuals diagnosed with CdLS, aged between 4 and 21 years, was assessed using the Kidslife questionnaire. Specifically, the influence of 14 risk factors on overall QoL and 8 of its domains was analyzed. RESULTS: The study revealed below-median QoL (45.3 percentile), with the most affected domains being physical well-being, personal development, and self-determination. When classifying patients based on their QoL and affected domains, variants in the NIPBL gene, clinical scores ≥11, and severe behavioral and communication issues were found to be the main risk factors. CONCLUSIONS: We emphasize the need for a comprehensive approach to CdLS that encompasses clinical, molecular, psychosocial, and emotional aspects. The "Kidslife questionnaire" proved to be a useful tool for evaluating QoL, risk factors, and the effectiveness of implemented strategies. In this study, we underscore the importance of implementing corrective measures to improve the clinical score. Furthermore, we highlight the necessity of applying specific therapies for behavioral problems after ruling out underlying causes such as pain or gastroesophageal reflux and implementing measures that facilitate communication and promote social interaction.
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Cornelia de Lange syndrome (CdLS) is a rare congenital developmental disorder with multisystemic involvement. The clinical presentation is highly variable, but the classic phenotype, characterized by distinctive craniofacial features, pre- and postnatal growth retardation, extremity reduction defects, hirsutism and intellectual disability can be distinguished from the nonclassic phenotype, which is generally milder and more difficult to diagnose. In addition, the clinical features overlap with those of other neurodevelopmental disorders, so the use of consensus clinical criteria and artificial intelligence tools may be helpful in confirming the diagnosis. Pathogenic variants in NIPBL, which encodes a protein related to the cohesin complex, have been identified in more than 60% of patients, and pathogenic variants in other genes related to this complex in another 15%: SMC1A, SMC3, RAD21, and HDAC8. Technical advances in large-scale sequencing have allowed the description of additional genes (BRD4, ANKRD11, MAU2), but the lack of molecular diagnosis in 15% of individuals and the substantial clinical heterogeneity of the syndrome suggest that other genes and mechanisms may be involved. Although there is no curative treatment, there are symptomatic/palliative treatments that paediatricians should be aware of. The main medical complication in classic SCdL is gastro-esophageal reflux (GER), which should be treated early.
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Síndrome de Cornelia de Lange , Fenotipo , Niño , Humanos , Síndrome de Cornelia de Lange/diagnóstico , Síndrome de Cornelia de Lange/genéticaRESUMEN
BACKGROUND: Cornelia de Lange syndrome (CdLS) is a multisystem genetic disorder, and cases caused by variants in the structural maintenance of chromosomes protein 3 (SMC3) gene are uncommon. Here, we report two cases of CdLS associated with novel pathogenic variants in SMC3 from two Chinese families. METHODS: Clinical presentations of two patients with CdLS were evaluated, and specimens from the patients and other family members were collected for Trio-based whole-exome sequencing. Pyrosequencing, chip-based digital PCR, minigene splicing assay, and in silico analysis were carried out to elucidate the impact of novel variants. RESULTS: Novel heterozygous variants in SMC3 were identified in each proband. One harbored a novel splicing and mosaic variant (c.2535+1G>A) in SMC3. The mutated allele G>A conversion was approximately 23.1% by digital PCR, which indicated that 46.2% of peripheral blood cells had this variant. Additionally, in vitro minigene splicing analysis validated that the c.2535+1G>A variant led to an exon skipping in messenger RNA splicing. The other carried a heterozygous variant (c.435C>A), which was predicted to be pathogenic as well as significantly altered in local electrical potential. The former showed multiple abnormalities and marked clinical severity, and the latter mainly exhibited a speech developmental disorder and slightly facial anomalies. CONCLUSION: Both patients were clinically diagnosed with Cornelia de Lange syndrome 3 (CdLS3). The newly identified SMC3 gene variants can expand the understanding of CdLS3 and provide reliable evidence for genetic counseling to the affected family.
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Proteínas de Ciclo Celular , Proteínas Cromosómicas no Histona , Síndrome de Cornelia de Lange , Femenino , Humanos , Masculino , Proteínas de Ciclo Celular/genética , Proteoglicanos Tipo Condroitín Sulfato , Proteínas Cromosómicas no Histona/genética , Síndrome de Cornelia de Lange/genética , Síndrome de Cornelia de Lange/patología , Heterocigoto , Mutación , Linaje , Fenotipo , Empalme del ARNRESUMEN
Next-generation phenotyping (NGP) can be used to compute the similarity of dysmorphic patients to known syndromic diseases. So far, the technology has been evaluated in variant prioritization and classification, providing evidence for pathogenicity if the phenotype matched with other patients with a confirmed molecular diagnosis. In a Nigerian cohort of individuals with facial dysmorphism, we used the NGP tool GestaltMatcher to screen portraits prior to genetic testing and subjected individuals with high similarity scores to exome sequencing (ES). Here, we report on two individuals with global developmental delay, pulmonary artery stenosis, and genital and limb malformations for whom GestaltMatcher yielded Cornelia de Lange syndrome (CdLS) as the top hit. ES revealed a known pathogenic nonsense variant, NM_133433.4: c.598C>T; p.(Gln200*), as well as a novel frameshift variant c.7948dup; p.(Ile2650Asnfs*11) in NIPBL. Our results suggest that NGP can be used as a screening tool and thresholds could be defined for achieving high diagnostic yields in ES. Training the artificial intelligence (AI) with additional cases of the same ethnicity might further increase the positive predictive value of GestaltMatcher.
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Síndrome de Cornelia de Lange , Fenotipo , Humanos , Síndrome de Cornelia de Lange/genética , Síndrome de Cornelia de Lange/diagnóstico , Síndrome de Cornelia de Lange/patología , Masculino , Femenino , Niño , Nigeria , Preescolar , Proteínas de Ciclo Celular/genética , Secuenciación del Exoma , Pruebas Genéticas/métodos , Secuenciación de Nucleótidos de Alto Rendimiento , LactanteRESUMEN
Cornelia de Lange syndrome (CdLS) is a complex genetic disorder with distinct facial features, growth limitations, and limb anomalies. Its broad clinical spectrum presents significant challenges in pediatric diagnosis and management. Due to cohesin complex mutations, the disorder's variable presentation requires extensive research to refine care and improve outcomes. This article provides a case series review of pediatric CdLS patients alongside a comprehensive literature review, exploring clinical variability and the relationship between genotypic changes and phenotypic outcomes. It also discusses the evolution of diagnostic and therapeutic techniques, emphasizing innovations in genetic testing, including detecting mosaicism and novel genetic variations. The aim is to synthesize case studies with current research to advance our understanding of CdLS and the effectiveness of management strategies in pediatric healthcare. This work highlights the need for an integrated, evidence-based approach to diagnosis and treatment. It aims to fill existing research gaps and advocate for holistic care protocols and tailored treatment plans for CdLS patients, ultimately improving their quality of life.
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Thanks to a long-read sequencing (LRS) approach, in this study, we have reported a molecularly solved case of a proband with a clinical diagnosis of Cornelia de Lange syndrome (CDLS), which is a multisystemic disorder whose causative molecular defects involve cohesin complex genes, with NIPBL located at 5p13.2 accounting for approximately 50%-60% of CDLS cases. The first-tier tests revealed an abnormal karyotype 46,XY,t(5;15)(p13;q25)dn and a preserved NIPBL sequencing. Copy number variants (CNVs) at the translocation breakpoints, in disease genes, or in probably pathogenic loci were excluded by a-CGH analysis. Through fluorescence in situ hybridization (FISH) analysis on derivative chromosome 5, the breakpoint was relocated 3 Mb far from NIPBL 5'UTR, which seemed fully maintained as FISH-probe mapping to the gene showed no split signals. Moreover, tri-color FISH revealed an apparently balanced paracentric inversion including NIPBL on derivative 5. Based on the strong clinical suspicion, we evaluated the NIPBL transcript by RT-qPCR that revealed a normal amount of transcript till exon 22 and a halved amount of the transcript from exon 23 to 3'UTR, indicating the expression of a truncated transcript probably leading to a defective protein. Despite RT-qPCR confirmed the patient's CDLS clinical diagnosis, the molecular mechanism underlying this event remained to be an unsolved challenge for years. The LRS approach with nanopore technologies was able to fill the gap in this complex scenario and highlighted a chromothripsis event marked out at 5p13.2 by 36 breaks clustered in a 7.3-Mb region. The NIPBL gene was disrupted by 16 breaks and the resulting fragments were relocated in different positions and orientations. LRS confirmed the previous findings, and it has been proven to be crucial to define the complex chromosomal rearrangement in this patient which escaped current diagnostic investigations. Its application in the clinical practice will contribute to solve the unsolved.
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BACKGROUND: Cornelia de Lange (CdLS) is a rare genetic disorder that affects most body systems. Variants in multiple genes including NIPBL and SMC1A, can cause the syndrome. To date, literature on genotype-phenotype associations in individuals with CdLS is extremely limited, although studies suggest some differences in clinical phenotype severity across variants. This study aimed to examine and compare neurobehavioral differences and developmental variability across CdLS genes, specifically NIPBL and SMC1A, and identify genotype-phenotype correlations. PARTICIPANTS AND METHODS: This patient-reported outcomes study included accessing data from the Coordination of Rare Diseases registry at Sanford. Parents of a total of 26 children/adults with CdLS and a known variant in NIPBL (Mean age = 20.46 years, SD = 11.21) and 12 with a known variant in SMC1A (Mean age = 11.08 years, SD = 9.04) completed a series of questionnaires regarding their child's developmental history. This included attainment of common language and motor milestones, intervention history, and behavior functioning. Developmental history and reported behavior regulation difficulties were compared across variant groups. RESULTS: Overall, individuals with a pathogenic variant in NIPBL or SMC1A were similarly delayed across motor and language milestones with about 70% not using phrase speech and 30-50% not walking by 5 years of age. However, those with NIPBL variants showed more severity in behavioral phenotype, namely with more repetitive behaviors, tantrums, and withdrawn behaviors. In addition, these individuals were more likely than those with SMC1A variants to demonstrate self-injurious behaviors, and anxiety. Both groups yielded a similar proportion of participants who participated in speech and occupational therapy, however those with SMC1A variants were more likely to engage in physical therapy. Both clinical groups report low rate of communicative or assistive device use despite a large proportion of participants never mastering single word or sentence use. CONCLUSIONS: Study results are consistent with recent investigations highlighting more severe behavioral phenotype, particularly autistic features, anxiety, and behavior regulation challenges, among those with NIPBL variants albeit comparable developmental milestones. Both groups endorsed very elevated attention problems. Findings highlight importance of early interventions, including behavioral health services.
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Proteínas de Ciclo Celular , Síndrome de Cornelia de Lange , Niño , Adulto , Humanos , Adulto Joven , Proteínas de Ciclo Celular/genética , Síndrome de Cornelia de Lange/genética , Proteínas Cromosómicas no Histona/genética , Fenotipo , Estudios de Asociación GenéticaRESUMEN
BACKGROUND: Gaze following difficulties are considered an early marker of autism, thought likely to cumulatively impact the development of social cognition, language and social skills. Subtle differences in gaze following abilities may contribute to the diverse range social and communicative autistic characteristics observed across people with genetic syndromes, such as Cornelia de Lange (CdLS) and fragile X (FXS) syndromes. AIMS: To compare profiles of 1) visual attention to the eye region at critical points of the attention direction process, 2) whether children follow the gaze cue to the object, and 3) participant looking time to the target object following the gaze cue between groups and conditions. MATERIALS AND METHODS: Children with CdLS (N = 11) and FXS (N = 8) and autistic (N = 22) and neurotypical (N = 15) children took part in a passive viewing paradigm adapted from Senju and Csibra (2008), in which videos of a central cue (ball/cartoon face/human face) directed attention towards one of two objects. Visual attention patterns were recorded via eye tracking technology. RESULTS: Neurotypical children were used as a reference group against which the autistic, CdLS and FXS groups were compared. Although autistic children looked at the eye region for significantly less time, they looked at the target object as frequently and for a similar duration as neurotypical children. Children with FXS looked at the target as frequently as neurotypical children but looked at it for comparatively less time. Both neurotypical children and children with CdLS frequently looked at the eye region, but children with CdLS were less likely to look at the target than neurotypical children. CONCLUSIONS: Findings provide preliminary evidence of unique patterns of visual attention and gaze following strategies in children with CdLS, children with FXS and autistic children. These unique gaze following patterns may underpin the distinct profiles of social and communication autistic traits observed between these groups.
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Trastorno Autístico , Síndrome de Cornelia de Lange , Síndrome del Cromosoma X Frágil , Niño , Humanos , Comunicación , LenguajeAsunto(s)
Síndrome de Cornelia de Lange , Hirsutismo , Imagenología Tridimensional , Ultrasonografía Prenatal , Humanos , Femenino , Ultrasonografía Prenatal/métodos , Hirsutismo/diagnóstico por imagen , Embarazo , Síndrome de Cornelia de Lange/diagnóstico por imagen , Imagenología Tridimensional/métodos , AdultoRESUMEN
Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 14 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism, reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated an overall milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, and some had alternative symptomatologies with rational biological links to SMC3. Analyses of tumor and model system transcriptomic data and epigenetic data in a subset of cases suggest that SMC3 pLoF variants reduce SMC3 expression but do not strongly support clustering with functional genomic signatures of typical CdLS. Our finding of substantial population-scale LoF intolerance in concert with variable growth and developmental features in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multilayered genomic data paired with careful phenotyping.
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Síndrome de Cornelia de Lange , Discapacidad Intelectual , Humanos , Proteínas de Ciclo Celular/genética , Proteoglicanos Tipo Condroitín Sulfato/genética , Proteínas Cromosómicas no Histona/genética , Síndrome de Cornelia de Lange/genética , Heterocigoto , Discapacidad Intelectual/genética , Mutación , FenotipoRESUMEN
SMC1A epilepsy syndrome or developmental and epileptic encephalopathy-85 with or without midline brain defects (DEE85, OMIM #301044) is an X-linked neurologic disorder associated with mutations of the SMC1A gene, which is also responsible for about 5% of patients affected by Cornelia de Lange syndrome spectrum (CdLS). Only described in female patients, SMC1A epilepsy syndrome is characterized by the onset of severe refractory epileptic seizures in the first year of life, global developmental delay, a variable degree of intellectual disability, and dysmorphic facial features not typical of CdLS. This was a descriptive observational study for the largest international cohort with this specific disorder. The main goal of this study was to improve the knowledge of the natural history of this phenotype with particular attention to the psychomotor development and the epilepsy data. The analyzed cohort shows normal prenatal growth with the subsequent development of postnatal microcephaly. The incidence of neonatal problems (seizures and respiratory compromise) is considerable (51.4%). There is a significant prevalence of central nervous system (20%) and cardiovascular malformations (20%). Motor skills are generally delayed. The presence of drug-resistant epilepsy is confirmed; the therapeutic role of a ketogenic diet is still uncertain. The significant regression of previously acquired skills following the onset of seizures has been observed. Facial dysmorphisms are variable and no patient shows a classic CdLS phenotype. To sum up, SMC1A variants caused drug-resistant epilepsy in these patients, more than two-thirds of whom were shown to progress to developmental and epileptic encephalopathy. The SMC1A gene variants are all different from each other (apart from a couple of monozygotic twins), demonstrating the absence of a mutational hotspot in the SMC1A gene. Owing to the absence of phenotypic specificity, whole-exome sequencing is currently the diagnostic gold standard.
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Proteínas de Ciclo Celular , Proteínas Cromosómicas no Histona , Mutación , Humanos , Femenino , Masculino , Proteínas de Ciclo Celular/genética , Proteínas Cromosómicas no Histona/genética , Preescolar , Lactante , Mutación/genética , Niño , Epilepsia/genética , Epilepsia/epidemiología , Epilepsia/patología , Epilepsia/diagnóstico , Fenotipo , Estudios de Cohortes , Adolescente , Recién Nacido , Síndromes Epilépticos/genética , Síndromes Epilépticos/epidemiología , Síndrome de Cornelia de Lange/genética , Síndrome de Cornelia de Lange/epidemiología , Síndrome de Cornelia de Lange/patologíaRESUMEN
Cornelia de Lange's syndrome (CDLS) is a multisystem genetic syndrome characterized by well-defined physical, intellectual, and behavioral characteristics. The diagnosis of CDLS is typically done clinically after birth; however, recent studies have demonstrated the ability to use prenatal ultrasound and whole-exome sequencing to diagnose CDLS prenatally. Here we present a prenatal case in which multiple fetal anomalies were identified on ultrasound at 20 weeks of gestation. Use of whole-exome sequencing allowed for successful diagnosis of CDLS in this fetus prenatally.
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BACKGROUND: Cornelia de Lange Syndrome (CdLS) is a rare genetic disorder characterized by a range of physical, cognitive, and behavioral abnormalities. This study aimed to perform a comprehensive review of the literature on CdLS and investigate two cases of CdLS with distinct phenotypes that underwent WES to aid in their diagnosis. METHODS: We conducted a comprehensive review of the literature on CdLS along with performing whole-exome sequencing on two CdLS patients with distinct phenotypes, followed by Sanger sequencing validation and in-silico analysis. RESULTS: The first case exhibited a classic CdLS phenotype, but the initial WES analysis of blood-derived DNA failed to identify any mutations in CdLS-related genes. However, a subsequent WES analysis of skin-derived DNA revealed a novel heterozygous mutation in the NIPBL gene (NM_133433.4:c.6534_6535del, p.Met2178Ilefs*8). The second case was presented with a non-classic CdLS phenotype, and WES analysis of blood-derived DNA identified a heterozygous missense variant in the SMC1A gene (NM_006306.4:c.2320G>A, p.Asp774Asn). CONCLUSIONS: The study shows the importance of considering mosaicism in classic CdLS cases and the value of WES for identifying genetic defects. These findings contribute to our understanding of CdLS genetics and underscore the need for comprehensive genetic testing to enhance the diagnosis and management of CdLS patients.
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Proteínas de Ciclo Celular , Síndrome de Cornelia de Lange , Humanos , Proteínas de Ciclo Celular/genética , Exoma , Mutación , Fenotipo , ADN , Biopsia , Síndrome de Cornelia de Lange/genética , Síndrome de Cornelia de Lange/diagnósticoRESUMEN
The human STAG2 protein is an essential component of the cohesin complex involved in cellular processes of gene expression, DNA repair, and genomic integrity. Somatic mutations in the STAG2 sequence have been associated with various types of cancer, while congenital variants have been linked to developmental disorders such as Mullegama-Klein-Martinez syndrome, X-linked holoprosencephaly-13, and Cornelia de Lange syndrome. In the cohesin complex, the direct interaction of STAG2 with DNA and with NIPBL, RAD21, and CTCF proteins has been described. The function of STAG2 within the complex is still unknown, but it is related to its DNA binding capacity and is modulated by its binding to the other three proteins. Every missense variant described for STAG2 is located in regions involved in one of these interactions. In the present work, we model the structure of 12 missense variants described for STAG2, as well as two other variants of NIPBl and two of RAD21 located at STAG2 interaction zone, and then analyze their behavior through molecular dynamic simulations, comparing them with the same simulation of the wild-type protein. This will allow the effects of variants to be rationalized at the atomic level and provide clues as to how STAG2 functions in the cohesin complex.
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Cohesinas , Discapacidades del Desarrollo , Humanos , Factor de Unión a CCCTC/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cohesinas/genética , Síndrome de Cornelia de Lange/genética , ADN , Mutación , Mutación Missense , Discapacidades del Desarrollo/genéticaRESUMEN
Post-zygotic mosaicism is a well-known biological phenomenon characterized by the presence of genetically distinct lineages of cells in the same individual due to post-zygotic de novo mutational events. It has been identified in about 13% of Cornelia de Lange (CdLS) syndrome patients with a molecular diagnosis, an unusual high frequency. Here, we report the case of a patient affected by classic CdLS harboring post-zygotic mosaicism for two different likely pathogenic variants at the same nucleotide position in NIPBL. Double somatic mosaicism has never been reported in CdLS and only rarely recognized in human diseases. Possible pathogenetic mechanisms are discussed.
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Síndrome de Cornelia de Lange , Humanos , Síndrome de Cornelia de Lange/diagnóstico , Síndrome de Cornelia de Lange/genética , Proteínas de Ciclo Celular/genética , Mosaicismo , FenotipoRESUMEN
Objective:To analyze the clinical characteristics and genetic features of SMC1A gene related disorders. Methods:The data of 5 children with SMC1A gene variants were collected from Children′s Hospital of Fudan University from February 2018 to January 2022. The clinical features, electroencephalogram (EEG), brain imaging and gene testing results were summarized. Results:Among the 5 patients, 4 are females and 1 is male. Two female cases are siblings. One boy had dysmorphic features, consisting of bilateral ptosis, synophrys, a short nose and upturned nasal tip. He also had patent foramen ovale plus atrial septal defect, unilateral cryptorchidism and microcephaly. Three cases had microcephaly. Two girls had patent foramen ovale, and 2 girls had microcephaly. Four cases had epilepsy, and age at seizure onset ranged from 2 to 52 months. Multiple seizure types were observed, including bilateral tonic clonic seizures in 2 patients, and focal seizures in 3 patients. The seizures in 3 cases were in cluster. All patients had developmental delay, including 1 patient with mild and 4 patients with moderate to severe developmental delay. Three patients had slow background activity in EEG. Interictal EEG showed abnormal discharges in 4 patients, including focal discharges in 3 cases and generalized discharges in 1 case. Brain magnetic resonance imaging was normal in 3 patients and showed mild cortical thickening in 1 case. All cases harbored 4 SMC1A gene variants, including 2 missense variants and 2 frameshift variants (c.580_587del, c.2699delG, c.3362G>A, c.1486C>T). Three cases harbored heterozygous SMC1A variants and 2 cases carried somatic mosaic SMC1A variants with 17.5% and 88.1% mosaicism in peripheral blood. The follow-up lasted for 3 months to 4 years. The epilepsy was refractory in 2 cases. During the follow-up, all cases had very slow developmental progress or developmental retardation. All cases had different levels of growth retardation. The scores of Cornelia de Lange syndrome (CdLS) phenotypes in 5 cases were 2-6. One case had the combined phenotypes of atypical CdLS and developmental epileptic encephalopathy (DEE). The phenotype was atypical CdLS in 1 case and DEE in 1 case. The phenotypes of 2 cases with SMC1A missense variants were mild, manifesting as non-refractory epilepsy and moderate to severe developmental delay. Conclusions:All of cases with SMC1A gene variants have developmental delay. Most of the patients have clusters of seizures and some dysmorphisms. The phenotypes of SMC1A gene related disorders are diverse. Except CdLS and DEE, there are some patients with mild phenotype due to missense variants of SMC1A gene.
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ABSTRACT Purpose: to describe the audiological profile of patients with Cornelia de Lange syndrome (CdLS) in an integrative review of the literature. Methods: after developing the research question, articles were searched in six databases (EMBASE, ISI of Knowledge, LILACS, MEDLINE/PubMed, SciELO, and Scopus) and in sources of information (Google Scholar, OpenGrey, and ProQuest), with the following descriptors: audiology, hearing loss, deafness, hearing disorders, and Cornelia de Lange syndrome. This review was registered in Prospero under number CRD42020191481. National and international studies were considered for analysis, using the PECO acronym. The risk of bias in the studies was analyzed with Joanna Briggs Institute protocols. Then, the studies were described and analyzed. Results: of the 1,080 articles found, 12 met the inclusion criteria. Audiological results showed that individuals with CdLS can have hearing loss - conductive hearing losses were the most frequent impairments, corresponding to 49.20% of individuals with CdLS assessed, followed by sensorineural hearing losses (13.49%). The degrees of hearing loss ranged from mild to profound. Conclusion: individuals presented with CdLS often have hearing loss, mainly due to middle ear changes, with degrees ranging from mild to profound.
RESUMO Objetivo: descrever o perfil audiológico de pacientes com Síndrome de Cornelia de Lange (SCdL), por meio de uma revisão integrativa da literatura. Métodos: após formulação da pergunta, realizou-se uma busca em seis bases de dados (Embase, ISI of Knowledge, Lilacs, Medline/PubMed, Scielo e Scopus), e fontes de informação (Google Acadêmico, OpenGrey e Proquest), com os descritores: audiologia, perda auditiva, surdez, transtornos da audição e Síndrome de Cornelia de Lange. Esta revisão foi cadastrada no Próspero, sob número CRD42020191481. Foram considerados para análise, estudos nacionais e internacionais, utilizando o direcionamento do acrônimo PECO. Para análise do risco de viés dos estudos, utilizou-se os protocolos do Instituto Joanna Briggs. Após isso, os estudos foram descritos e analisados. Resultados: dos 1.080 artigos encontrados, 12 atenderam aos critérios de inclusão. Nos resultados audiológicos, constatou-se que indivíduos com SCdL podem apresentar perda auditiva, sendo que o comprometimento pela perda auditiva condutiva foi o mais frequente, correspondendo a 49,20% dos indivíduos com SCdL avaliados, seguido pela perda auditiva neurossensorial (13,49%). O grau de perda auditiva variou de leve à profundo. Conclusão: indivíduos com SCdL frequentemente apresentam perda auditiva, decorrente principalmente de alterações de orelha média, com graus variando de leve a profundo.