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Molecular Syndromology Jan 2020Myhre syndrome is a rare autosomal dominant multisystemic disorder. Typical features of this disorder include distinctive facial appearance, deafness, intellectual...
Myhre syndrome is a rare autosomal dominant multisystemic disorder. Typical features of this disorder include distinctive facial appearance, deafness, intellectual disability, cardiovascular abnormalities, short stature, brachydactyly, and skeletal anomalies. Gain-of-function mutations in the gene are responsible for this syndrome. Herein, we present a 9.6-year-old Turkish girl with molecularly confirmed Myhre syndrome who had novel findings including bilateral Axenfield Rieger anomaly with secondary glaucoma and bilateral enlarged vestibular aqueducts.
PubMed: 32021609
DOI: 10.1159/000504829 -
GeroScience Jun 2021SMAD4 encodes a member of the SMAD family of proteins involved in the TGF-β signaling pathway. Potentially heritable, autosomal dominant, gain-of-function heterozygous...
SMAD4 mutations and cross-talk between TGF-β/IFNγ signaling accelerate rates of DNA damage and cellular senescence, resulting in a segmental progeroid syndrome-the Myhre syndrome.
SMAD4 encodes a member of the SMAD family of proteins involved in the TGF-β signaling pathway. Potentially heritable, autosomal dominant, gain-of-function heterozygous variants of SMAD4 cause a rare developmental disorder, the Myhre syndrome, which is associated with a wide range of developmental and post-developmental phenotypes that we now characterize as a novel segmental progeroid syndrome. Whole-exome sequencing of a patient referred to our International Registry of Werner Syndrome revealed a heterozygous p.Arg496Cys variant of the SMAD4 gene. To investigate the role of SMAD4 mutations in accelerated senescence, we generated cellular models overexpressing either wild-type SMAD4 or mutant SMAD4-R496C in normal skin fibroblasts. We found that cells expressing the SMAD4-R496C mutant exhibited decreased proliferation and elevated expression of cellular senescence and inflammatory markers, including IL-6, IFNγ, and a TGF-β target gene, PAI-1. Here we show that transient exposure to TGF-β, an inflammatory cytokine, followed by chronic IFNγ stimulation, accelerated rates of senescence that were associated with increased DNA damage foci and SMAD4 expression. TGF-β, IFNγ, or combinations of both were not sufficient to reduce proliferation rates of fibroblasts. In contrast, TGF-β alone was able to induce preadipocyte senescence via induction of the mTOR protein. The mTOR inhibitor rapamycin mitigated TGF-β-induced expression of p21, p16, and DNA damage foci and improved replicative potential of preadipocytes, supporting the cell-specific response to this cytokine. These findings collectively suggest that persistent DNA damage and cross-talk between TGF-β/IFNγ pathways contribute to a series of molecular events leading to cellular senescence and a segmental progeroid syndrome.
Topics: Cellular Senescence; Cryptorchidism; DNA Damage; Facies; Growth Disorders; Hand Deformities, Congenital; Humans; Intellectual Disability; Mutation; Smad4 Protein; Transforming Growth Factor beta
PubMed: 33428109
DOI: 10.1007/s11357-020-00318-6 -
American Journal of Medical Genetics.... Dec 2019Myhre syndrome is a rare multisystem connective tissue disorder, characterized by short stature, facial dysmorphology, variable intellectual disability, skeletal...
Myhre syndrome is a rare multisystem connective tissue disorder, characterized by short stature, facial dysmorphology, variable intellectual disability, skeletal abnormalities, arthropathy, cardiopathy, laryngotracheal anomalies, and stiff skin. So far, all molecularly confirmed cases harbored a de novo heterozygous gain-of-function mutation in SMAD4, encoding the SMAD4 transducer protein required for both transforming growth factor-beta and bone morphogenic proteins signaling. We report on four novel patients (one female proband and her two affected children, and one male proband) with Myhre syndrome harboring the recurrent c.1486C>T (p.Arg496Cys) mutation in SMAD4. The female proband presented with a congenital heart defect, vertebral anomalies, and facial dysmorphic features. She developed severe tracheal stenosis requiring a total laryngectomy. With assisted reproductive treatment, she gave birth to two affected children. The second proband presented with visual impairment following lensectomy in childhood, short stature, brachydactyly, stiff skin, and decreased peripheral sensitivity. Transmission electron microscopy (TEM) of the dermis shows irregular elastin cores with globular deposits and almost absent surrounding microfibrils and suggests age-related increased collagen deposition. We report on the first familial case of Myhre syndrome and illustrate the variable clinical spectrum of the disorder. Despite the primarily fibrotic nature of the disease, TEM analysis mainly indicates elastic fiber anomalies.
Topics: Adult; Alleles; Amino Acid Substitution; Biopsy; Cryptorchidism; Facies; Female; Genotype; Growth Disorders; Hand Deformities, Congenital; Humans; Intellectual Disability; Male; Middle Aged; Mutation; Phenotype; Radiography; Recurrence; Skin; Smad4 Protein
PubMed: 31595668
DOI: 10.1002/ajmg.a.61377 -
American Journal of Medical Genetics.... May 2022Tetralogy of Fallot (ToF) can be associated with a wide range of extracardiac anomalies, with an underlying etiology identified in approximately 10% of cases....
Tetralogy of Fallot (ToF) can be associated with a wide range of extracardiac anomalies, with an underlying etiology identified in approximately 10% of cases. Individuals affected with Myhre syndrome due to recurrent SMAD4 mutations frequently have cardiovascular anomalies, including congenital heart defects. In addition to two patients in the literature with ToF, we describe five additional individuals with Myhre syndrome and classic ToF, ToF with pulmonary atresia and multiple aorto-pulmonary collaterals, and ToF with absent pulmonary valve. Aorta hypoplasia was documented in one patient and suspected in another two. In half of these individuals, postoperative cardiac dysfunction was thought to be more severe than classic postoperative ToF repair. There may be an increase in right ventricular pressure, and right ventricular dysfunction due to free pulmonic regurgitation. Noncardiac developmental abnormalities in our series and the literature, including corectopia, heterochromia iridis, and congenital miosis suggest an underlying defect of neural crest cell migration in Myhre syndrome. We advise clinicians that Myhre syndrome should be considered in the genetic evaluation of a child with ToF, short stature, unusual facial features, and developmental delay, as these children may be at risk for increased postoperative morbidity. Additional research is needed to investigate the hypothesis that postoperative hemodynamics in these patients may be consistent with restrictive myocardial physiology.
Topics: Cryptorchidism; Facies; Growth Disorders; Hand Deformities, Congenital; Heart Defects, Congenital; Humans; Intellectual Disability; Male; Neural Crest; Phenotype; Smad4 Protein; Tetralogy of Fallot
PubMed: 35025139
DOI: 10.1002/ajmg.a.62645 -
Pediatric and Developmental Pathology :... 2022Myhre syndrome, caused by pathogenic variants in , is characterized by compact body habitus with short stature, distinctive craniofacial appearance, stiff skin,...
Myhre syndrome, caused by pathogenic variants in , is characterized by compact body habitus with short stature, distinctive craniofacial appearance, stiff skin, cardiovascular abnormalities (valve stenosis, coarctation, hypoplasia, or stenosis of aorta), effusions of potential spaces (pericardium, pleura, peritoneum), restricted movement of the joints (including thorax), and hearing loss. Lung and airway disease has been reported, but not always well-defined, to include interstitial lung disease, large airway obstruction, and pulmonary arterial hypertension. Excessive fibroproliferation of tissues especially following trauma or surgical instrumentation has been recognized, although these may also present spontaneously. We report the pathologic features of 1 new patient with progressive choanal stenosis, and 22 literature cases, including the expanded history of 5 patients (3 who died). Examination of patient tissues documents cellular fibroproliferation and deposition of excessive extracellular matrix explaining some of the observed clinical features of Myhre syndrome. Excessive fibrosis is noted in multiple tissues, especially heart, lung, and upper and lower airways. Our research provides the first systematic review to provide a knowledge base of gross and pathologic findings in Myhre syndrome.
Topics: Male; Humans; Constriction, Pathologic; Gain of Function Mutation; Hand Deformities, Congenital; Facies; Smad4 Protein
PubMed: 36120950
DOI: 10.1177/10935266221079569 -
American Journal of Medical Genetics.... Dec 2015Myhre syndrome, a connective tissue disorder characterized by deafness, restricted joint movement, compact body habitus, and distinctive craniofacial and skeletal...
Myhre syndrome, a connective tissue disorder characterized by deafness, restricted joint movement, compact body habitus, and distinctive craniofacial and skeletal features, is caused by heterozygous mutations in SMAD4. Cardiac manifestations reported to date have included patent ductus arteriosus, septal defects, aortic coarctation and pericarditis. We present five previously unreported patients with Myhre syndrome. Despite varied clinical phenotypes all had significant cardiac and/or pulmonary pathology and abnormal wound healing. Included herein is the first report of cardiac transplantation in patients with Myhre syndrome. A progressive and markedly abnormal fibroproliferative response to surgical intervention is a newly delineated complication that occurred in all patients and contributes to our understanding of the natural history of this disorder. We recommend routine cardiopulmonary surveillance for patients with Myhre syndrome. Surgical intervention should be approached with extreme caution and with as little invasion as possible as the propensity to develop fibrosis/scar tissue is dramatic and can cause significant morbidity and mortality.
Topics: Child; Cryptorchidism; Electrocardiography; Facies; Female; Growth Disorders; Hand Deformities, Congenital; Heart Diseases; Heart Transplantation; Humans; Intellectual Disability; Male; Mutation; Pregnancy; Smad4 Protein; Young Adult
PubMed: 26420300
DOI: 10.1002/ajmg.a.37273 -
American Journal of Medical Genetics.... Feb 2018Myhre syndrome is a rare autosomal dominant disorder caused by a narrow spectrum of missense mutations in the SMAD4 gene. Typical features of this disorder are...
Myhre syndrome is a rare autosomal dominant disorder caused by a narrow spectrum of missense mutations in the SMAD4 gene. Typical features of this disorder are distinctive facial appearance, deafness, intellectual disability, cardiovascular abnormalities, short stature, short hands and feet, compact build, joint stiffness, and skeletal anomalies. The clinical features generally appear during childhood and become more evident in older patients. Therefore, the diagnosis of this syndrome in the first years of life is challenging. We report a 2-year-old girl diagnosed with Myhre syndrome by whole exome sequencing (WES) that revealed the recurrent p.Ile500Val mutation in the SMAD4 gene. Our patient presented with growth deficiency, dysmorphic features, tetralogy of Fallot, and corectopia (also known as ectopia pupillae). The girl we described is the youngest patient with Myhre syndrome. Moreover, corectopia and tetralogy of Fallot have not been previously reported in this disorder.
Topics: Abnormalities, Multiple; Child, Preschool; Cryptorchidism; Facies; Female; Growth Disorders; Hand Deformities, Congenital; Humans; Intellectual Disability; Mutation; Phenotype; Pupil Disorders; Smad4 Protein; Tetralogy of Fallot; Exome Sequencing
PubMed: 29230941
DOI: 10.1002/ajmg.a.38560 -
European Journal of Pediatrics Oct 2016Myhre syndrome (OMIM 139210) is a rare developmental disorder inherited as an autosomal dominant trait and caused by a narrow spectrum of missense mutations in the SMAD4...
UNLABELLED
Myhre syndrome (OMIM 139210) is a rare developmental disorder inherited as an autosomal dominant trait and caused by a narrow spectrum of missense mutations in the SMAD4 gene. The condition features characteristic face, short stature, skeletal anomalies, muscle pseudohypertrophy, restricted joint mobility, stiff and thick skin, and variable intellectual disability. While most of the clinical features manifest during childhood, the diagnosis may be challenging during the first years of life. We report on the evolution of the clinical features of Myhre syndrome during childhood in a subject with molecularly confirmed diagnosis. The clinical records of 48 affected patients were retrospectively analysed to identify any early clinical signs characterizing this disorder and to better delineate its natural history. We also note that pericarditis and laryngotracheal involvement represent important life-threatening complications of Myhre syndrome that justify the recommendation for cardiological and ENT follow-up for these patients.
CONCLUSION
Short length/stature, short palpebral fissures, and brachydactyly with hyperconvex nails represent signs/features that might lead to the correct diagnosis in the first years of life and direct to the proper molecular analysis. We underline the clinical relevance of pericarditis and laryngotracheal stenosis as life-threatening complications of this disorder and the need for careful monitoring, in relation to their severity.
WHAT IS KNOWN
• The clinical and radiological signs of the disease in children older than 7-8 years. • Pericarditis, sometimes occurring with constrictive pericardium requiring pericardiectomy, has been reported as a recurrent feature but has not been adequately stressed in previous literature. What is New: • Short length/stature, short palpebral fissures, brachydactyly with hyperconvex nails represent clinical signs that might lead to diagnosis in the first years of life. • Review of the literature showed that pericarditis and laryngotracheal complications represent major recurrent issues in patients with Myhre syndrome.
Topics: Brachydactyly; Child; Cryptorchidism; Facies; Fingers; Growth Disorders; Hand Deformities, Congenital; Humans; Intellectual Disability; Male; Mutation, Missense; Nails, Malformed; Pericarditis; Phenotype; Radiography; Retrospective Studies; Smad4 Protein
PubMed: 27562837
DOI: 10.1007/s00431-016-2761-3 -
Journal of Clinical Medicine Jul 2023Disorders of immunity are poorly recognised in some rare multisystem genetic conditions. We aim to describe syndromic features and immunological defects in children with...
BACKGROUND
Disorders of immunity are poorly recognised in some rare multisystem genetic conditions. We aim to describe syndromic features and immunological defects in children with syndromic primary immunodeficiencies (sPIDs).
METHODS
This is a retrospective descriptive study of children aged 0-18 years with sPIDs under the care of the paediatric immunology service at the Bristol Royal Hospital for Children, United Kingdom, from January 2006 to September 2021.
RESULTS
sPIDs were identified in 36 patients. Genetic diagnoses which are not commonly associated with PIDs and not included in the International Union of Immunological Societies classification were present in 7/36 (19%): Trisomy 22, Arboleda-Tham syndrome, 2p16.3 deletion syndrome, supernumerary ring chromosome 20 syndrome, Myhre syndrome, Noonan syndrome, and trichothiodystrophy/Cockayne syndrome complex. Recurrent and/or severe infections were the most common clinical features (n = 33, 92%). Approximately half had combined immunodeficiency or antibody deficiency. The most common extra-immunological manifestations include dysmorphism (72%), disorders of nervous (78%), musculoskeletal (69%), haematology/lymphatic (58%), and gastrointestinal, hepatic/pancreatic (58%) systems.
CONCLUSIONS
Patients with sPIDs often have multiorgan involvement and some are non-immunologically mediated. There should be a low threshold to clinically assess and investigate for disorders of immunity in any patients with syndromic features especially when they present with recurrent/severe/opportunistic infections, features of immune dysregulation, autoinflammation or lymphoproliferation.
PubMed: 37568366
DOI: 10.3390/jcm12154964 -
Hereditary Cancer in Clinical Practice Dec 2023Juvenile polyposis syndrome (JPS), a rare autosomal dominant syndrome, affects one per 100 000 births, increasing lifetime cancer risk by 9 - 50%. Around 40-60% of JPS... (Review)
Review
BACKGROUND
Juvenile polyposis syndrome (JPS), a rare autosomal dominant syndrome, affects one per 100 000 births, increasing lifetime cancer risk by 9 - 50%. Around 40-60% of JPS cases are caused by disease-causing variants (DCV) in SMAD4 or BMPR1A genes, of which SMAD4 accounts for 20-30%.
OBJECTIVES
To characterise genotype-phenotype correlations between sites and types of variants within SMAD4 to JPS phenotypes, to inform diagnosis, screening, and management of JPS.
SEARCH METHODS
Online search databases utilised included Ovid MEDLINE, Embase Classic + Embase and PubMed, using search terms classified by MeSH on Demand. Adjacency operators, word truncation and Boolean operators were employed. 110 articles were included in the review, collating 291 variants from the literature.
RESULTS
In SMAD4 + JPS patients, most variants are located around SMAD4's MH2 domain (3' end). Extracolonic involvement, massive gastric polyposis and a more aggressive phenotype have been associated with SMAD4 + JPS, predisposing to gastric cancer. This has contributed to an overall higher incidence of GI cancers compared to other genes causing JPS, with DCVs mostly all within the MH2 domain. Genetically related allelic disorders of SMAD4 also have variants in this region, including hereditary haemorrhagic telangiectasia (HHT) alongside SMAD4 + JPS, and Myhre syndrome, independent of JPS. Similarly, with DCVs in the MH2 domain, Ménétrier's disease, hypertrophic osteoarthropathy and juvenile idiopathic arthritis have been seen in this population, whereas cardiac pathologies have occurred both alongside and independently of SMAD4 + JPS with DCVs in the MH1 domain.
CONCLUSION
Truncating and missense variants around the MH2 region of SMAD4 are most prevalent and pathogenic, thus should undergo careful surveillance. Given association with extracolonic polyposis and higher GI cancer risk, endoscopic screening should occur more frequently and at an earlier age in SMAD4 + JPS patients than in patients with other causative genes, with consideration of Ménétrier's disease on upper GI endoscopy. In addition, HHT should be evaluated within 6 months of diagnosis, alongside targeted clinical examination for extraintestinal manifestations associated with SMAD4 + JPS. This review may help modify clinical diagnosis and management of SMAD4 + JPS patients, and aid pathogenicity classification for SMAD4 DCVs through a better understanding of the phenotypes.
PubMed: 38066625
DOI: 10.1186/s13053-023-00267-z