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1.
Am J Med Genet A ; 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31595668

RESUMO

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.

2.
Genes (Basel) ; 10(7)2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31336972

RESUMO

Occipital horn syndrome (OHS) is a rare connective tissue disorder caused by pathogenic variants in ATP7A, encoding a copper transporter. The main clinical features, including cutis laxa, bony exostoses, and bladder diverticula are attributed to a decreased activity of lysyl oxidase (LOX), a cupro-enzyme involved in collagen crosslinking. The absence of large case series and natural history studies precludes efficient diagnosis and management of OHS patients. This study describes the clinical and molecular characteristics of two new patients and 32 patients previously reported in the literature. We report on the need for long-term specialized care and follow-up, in which MR angiography, echocardiography and spirometry should be incorporated into standard follow-up guidelines for OHS patients, next to neurodevelopmental, orthopedic and urological follow-up. Furthermore, we report on ultrastructural abnormalities including increased collagen diameter, mild elastic fiber abnormalities and multiple autophagolysosomes reflecting the role of lysyl oxidase and defective ATP7A trafficking as pathomechanisms of OHS.

3.
Genet Med ; 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31316167

RESUMO

PURPOSE: Congenital contractural arachnodactyly (CCA) is an autosomal dominant connective tissue disorder manifesting joint contractures, arachnodactyly, crumpled ears, and kyphoscoliosis as main features. Due to its rarity, rather aspecific clinical presentation, and overlap with other conditions including Marfan syndrome, the diagnosis is challenging, but important for prognosis and clinical management. CCA is caused by pathogenic variants in FBN2, encoding fibrillin-2, but locus heterogeneity has been suggested. We designed a clinical scoring system and diagnostic criteria to support the diagnostic process and guide molecular genetic testing. METHODS: In this retrospective study, we assessed 167 probands referred for FBN2 analysis and classified them into a FBN2-positive (n = 44) and FBN2-negative group (n = 123) following molecular analysis. We developed a 20-point weighted clinical scoring system based on the prevalence of ten main clinical characteristics of CCA in both groups. RESULTS: The total score was significantly different between the groups (P < 0.001) and was indicative for classifying patients into unlikely CCA (total score <7) and likely CCA (total score ≥7) groups. CONCLUSIONS: Our clinical score is helpful for clinical guidance for patients suspected to have CCA, and provides a quantitative tool for phenotyping in research settings.

4.
Hum Mutat ; 40(8): 1013-1029, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31021519

RESUMO

SATB2-associated syndrome (SAS) is an autosomal dominant neurodevelopmental disorder caused by alterations in the SATB2 gene. Here we present a review of published pathogenic variants in the SATB2 gene to date and report 38 novel alterations found in 57 additional previously unreported individuals. Overall, we present a compilation of 120 unique variants identified in 155 unrelated families ranging from single nucleotide coding variants to genomic rearrangements distributed throughout the entire coding region of SATB2. Single nucleotide variants predicted to result in the occurrence of a premature stop codon were the most commonly seen (51/120 = 42.5%) followed by missense variants (31/120 = 25.8%). We review the rather limited functional characterization of pathogenic variants and discuss current understanding of the consequences of the different molecular alterations. We present an expansive phenotypic review along with novel genotype-phenotype correlations. Lastly, we discuss current knowledge of animal models and present future prospects. This review should help provide better guidance for the care of individuals diagnosed with SAS.

5.
Am J Hum Genet ; 104(4): 758-766, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30929739

RESUMO

By using exome sequencing and a gene matching approach, we identified de novo and inherited pathogenic variants in KDM3B in 14 unrelated individuals and three affected parents with varying degrees of intellectual disability (ID) or developmental delay (DD) and short stature. The individuals share additional phenotypic features that include feeding difficulties in infancy, joint hypermobility, and characteristic facial features such as a wide mouth, a pointed chin, long ears, and a low columella. Notably, two individuals developed cancer, acute myeloid leukemia and Hodgkin lymphoma, in childhood. KDM3B encodes for a histone demethylase and is involved in H3K9 demethylation, a crucial part of chromatin modification required for transcriptional regulation. We identified missense and truncating variants, suggesting that KDM3B haploinsufficiency is the underlying mechanism for this syndrome. By using a hybrid facial-recognition model, we show that individuals with a pathogenic variant in KDM3B have a facial gestalt, and that they show significant facial similarity compared to control individuals with ID. In conclusion, pathogenic variants in KDM3B cause a syndrome characterized by ID, short stature, and facial dysmorphism.

6.
Acta Clin Belg ; : 1-9, 2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31025600

RESUMO

BACKGROUND: Turner syndrome (TS) is characterized by dysmorphism and body disproportion. TS women are also susceptible to a range of chronic disorders including arterial hypertension (AHT), osteoporosis, sensorineural hearing loss (SNHL), type 2 diabetes mellitus (DM2) and thyroid disease. The association between dysmorphism/body disproportion and chronic disease has never been studied in TS women. The effect of growth hormone treatment on body disproportion is also unclear. OBJECTIVES: to analyze dysmorphic features and body disproportion in TS women in relation to the presence of chronic disease and to document the effect of growth hormone therapy on body disproportion. METHOD: 76 adult TS women with a regular follow up at the TS clinic UZ Ghent were invited to participate. Detailed body measurements were performed in 44 volunteering TS women. Scoring systems for overall dysmorphism, craniofacial dysmorphism, thoracic and limb abnormalities and skeletal disproportion were developed. RESULTS: TS women with a higher dysmorphism score were more at risk for AHT (p = 0.04) as well as those with a higher sitting height/standing height ratio (p < 0.05). Prevalence of AHT, osteoporosis and DM 2 was lower in TS women treated with GH during childhood (p < 0.05). CONCLUSIONS: Adult TS women with relatively short legs or with more physical dysmorphic stigmata were more at risk for AHT. GH therapy does not seem to increase the risk of chronic disease on the long term.

7.
Oxid Med Cell Longev ; 2019: 8156592, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30800210

RESUMO

Ascorbate requiring Fe2+/2-oxoglutarate-dependent dioxygenases located in the nucleoplasm have been shown to participate in epigenetic regulation of gene expression via histone and DNA demethylation. Transport of dehydroascorbic acid is impaired in the endomembranes of fibroblasts from arterial tortuosity syndrome (ATS) patients, due to the mutation in the gene coding for glucose transporter GLUT10. We hypothesized that altered nuclear ascorbate concentration might be present in ATS fibroblasts, affecting dioxygenase activity and DNA demethylation. Therefore, our aim was to characterize the subcellular distribution of vitamin C, the global and site-specific changes in 5-methylcytosine and 5-hydroxymethylcytosine levels, and the effect of ascorbate supplementation in control and ATS fibroblast cultures. Diminished nuclear accumulation of ascorbate was found in ATS fibroblasts upon ascorbate or dehydroascorbic acid addition. Analyzing DNA samples of cultured fibroblasts from controls and ATS patients, a lower global 5-hydroxymethylcytosine level was found in ATS fibroblasts, which could not be significantly modified by ascorbate addition. Investigation of the (hydroxy)methylation status of specific regions in six candidate genes related to ascorbate metabolism and function showed that ascorbate addition could stimulate hydroxymethylation and active DNA demethylation at the PPAR-γ gene region in control fibroblasts only. The altered DNA hydroxymethylation patterns in patient cells both at the global level and at specific gene regions accompanied with decreased nuclear accumulation of ascorbate suggests the epigenetic role of vitamin C in the pathomechanism of ATS. The present findings represent the first example for the role of vitamin C transport in epigenetic regulation suggesting that ATS is a compartmentalization disease.


Assuntos
Artérias/anormalidades , Ácido Ascórbico/metabolismo , Núcleo Celular/metabolismo , Metilação de DNA/genética , Fibroblastos/metabolismo , Fibroblastos/patologia , Genoma Humano , Instabilidade Articular/genética , Dermatopatias Genéticas/genética , Malformações Vasculares/genética , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Células Cultivadas , Epigênese Genética , Humanos , Modelos Biológicos , PPAR gama/genética , PPAR gama/metabolismo
8.
J Med Genet ; 56(4): 252-260, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30661052

RESUMO

BACKGROUND: Pathogenic variants in SMAD3 cause thoracic aortic aneurysms and dissections, along with aneurysms and rupture of other arteries. Here, we examined differences in clinical presentation of aortic events (dissection or surgical repair of an aneurysm) with respect to age and variant type in an international cohort of individuals with SMAD3 variants. METHODS: Aortic status and events, vital status and clinical features were abstracted through retrospective review of medical records of 212 individuals with 51 unique SMAD3 variants, including haploinsufficiency (HI) and missense substitutions in the MH2 domain, as well as novel in-frame deletions and missense variants in the MH1 domain. RESULTS: Aortic events were documented in 37% of cases, with dissections accounting for 70% of events. The median age at first aortic event was significantly lower in individuals with SMAD3 MH2 missense variants than those with HI variants (42years vs 49 years; p=0.003), but there was no difference in frequency of aortic events by variant type. The cumulative risk of an aortic event was 50% at 54 years of age. No aortic events in childhood were observed. CONCLUSIONS: SMAD3 pathogenic variants cause thoracic aortic aneurysms and dissections in the majority of individuals with variable age of onset and reduced penetrance. Of the covariates examined, the type of underlying SMAD3 variant was responsible for some of this variation. Later onset of aortic events and the absence of aortic events in children associated with SMAD3 variants support gene-specific management of this disorder.

9.
Genet Med ; 2018 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-30293988

RESUMO

PURPOSE: RAC3 is an underexamined member of the Rho GTPase gene family that is expressed in the developing brain and linked to key cellular functions. De novo missense variants in the homolog RAC1 were recently associated with developmental disorders. In the RAC subfamily, transforming missense changes at certain shared residues have been observed in human cancers and previously characterized in experimental studies. The purpose of this study was to determine whether constitutional dysregulation of RAC3 is associated with human disease. METHODS: We discovered a RAC3 variant in the index case using genome sequencing, and searched for additional variants using international data-sharing initiatives. Functional effects of the variants were assessed using a multifaceted approach generalizable to most clinical laboratory settings. RESULTS: We rapidly identified five individuals with de novo monoallelic missense variants in RAC3, including one recurrent change. Every participant had severe intellectual disability and brain malformations. In silico protein modeling, and prior in vivo and in situ experiments, supported a transforming effect for each of the three different RAC3 variants. All variants were observed in databases of somatic variation in cancer. CONCLUSIONS: Missense variants in RAC3 cause a novel brain disorder, likely through a mechanism of constitutive protein activation.

10.
Dis Model Mech ; 11(10)2018 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-30355591

RESUMO

Targeted genome editing by CRISPR/Cas9 is extremely well fitted to generate gene disruptions, although precise sequence replacement by CRISPR/Cas9-mediated homology-directed repair (HDR) suffers from low efficiency, impeding its use for high-throughput knock-in disease modeling. In this study, we used next-generation sequencing (NGS) analysis to determine the efficiency and reliability of CRISPR/Cas9-mediated HDR using several types of single-stranded oligodeoxynucleotide (ssODN) repair templates for the introduction of disease-relevant point mutations in the zebrafish genome. Our results suggest that HDR rates are strongly determined by repair-template composition, with the most influential factor being homology-arm length. However, we found that repair using ssODNs does not only lead to precise sequence replacement but also induces integration of repair-template fragments at the Cas9 cut site. We observed that error-free repair occurs at a relatively constant rate of 1-4% when using different repair templates, which was sufficient for transmission of point mutations to the F1 generation. On the other hand, erroneous repair mainly accounts for the variability in repair rate between the different repair templates. To further improve error-free HDR rates, elucidating the mechanism behind this erroneous repair is essential. We show that the error-prone nature of ssODN-mediated repair, believed to act via synthesis-dependent strand annealing (SDSA), is most likely due to DNA synthesis errors. In conclusion, caution is warranted when using ssODNs for the generation of knock-in models or for therapeutic applications. We recommend the application of in-depth NGS analysis to examine both the efficiency and error-free nature of HDR events.This article has an associated First Person interview with the first author of the paper.

11.
Sci Rep ; 8(1): 15845, 2018 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-30374100

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

12.
J Am Coll Cardiol ; 72(6): 605-615, 2018 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-30071989

RESUMO

BACKGROUND: Thoracic aortic aneurysms progressively enlarge and predispose to acute aortic dissections. Up to 25% of individuals with thoracic aortic disease harbor an underlying Mendelian pathogenic variant. An evidence-based strategy for selection of genes to test in hereditary thoracic aortic aneurysm and dissection (HTAAD) helps inform family screening and intervention to prevent life-threatening thoracic aortic events. OBJECTIVES: The purpose of this study was to accurately identify genes that predispose to HTAAD using the Clinical Genome Resource (ClinGen) framework. METHODS: We applied the semiquantitative ClinGen framework to assess presumed gene-disease relationships between 53 candidate genes and HTAAD. Genes were classified as causative for HTAAD if they were associated with isolated thoracic aortic disease and were clinically actionable, triggering routine aortic surveillance, intervention, and family cascade screening. All gene-disease assertions were evaluated by a pre-defined curator-expert pair and subsequently discussed with an expert panel. RESULTS: Genes were classified based on the strength of association with HTAAD into 5 categories: definitive (n = 9), strong (n = 2), moderate (n = 4), limited (n = 15), and no reported evidence (n = 23). They were further categorized by severity of associated aortic disease and risk of progression. Eleven genes in the definitive and strong groups were designated as "HTAAD genes" (category A). Eight genes were classified as unlikely to be progressive (category B) and 4 as low risk (category C). The remaining genes were recent genes with an uncertain classification or genes with no evidence of association with HTAAD. CONCLUSIONS: The ClinGen framework is useful to semiquantitatively assess the strength of gene-disease relationships for HTAAD. Gene categories resulting from the curation may inform clinical laboratories in the development, interpretation, and subsequent clinical implications of genetic testing for patients with aortic disease.

13.
Exp Dermatol ; 2018 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-29952037

RESUMO

In ATP6V0A2-related cutis laxa, the skin phenotype varies from a wrinkly skin to prominent cutis laxa and typically associates with skeletal and neurological manifestations. The phenotype remains incompletely characterized, especially in adult patients. Glycosylation defects and reduced acidification of secretory vesicles contribute to the pathogenesis, but the consequences at the clinical level remain to be determined. Moreover, the morphology of the elastic fibres has not been studied in ATP6V0A2-related cutis laxa, nor its relation with potential clinical risks. We report on the extreme variability in ATP6V0A2-related cutis laxa in 10 novel patients, expand the phenotype with emphysema and von Willebrand disease and hypothesize on the pathogenesis that might link both with deficiency of glycosylation and with elastic fibre anomalies. Our data will affect clinical management of patients with ATP6V0A2-related cutis laxa.

14.
Circ Genom Precis Med ; 11(6): e002039, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29875124

RESUMO

BACKGROUND: The introduction of next-generation sequencing techniques has substantially increased the identification of new genetic variants and hence the necessity of accurate variant interpretation. In 2015, the American College of Medical Genetics and Genomics and the Association for Molecular Pathology proposed new variant interpretation guidelines. Gene-specific characteristics were, however, not considered, sometimes leading to inconsistent variant interpretation. METHODS: To allow a more uniform interpretation of variants in the FBN1 (fibrillin-1) gene, causing Marfan syndrome, we tailored these guidelines to this gene and disease. We adapted 15 of the 28 general criteria and classified 713 FBN1 variants previously identified in our laboratory as causal mutation or variant of uncertain significance according to these adapted guidelines. We then compared the agreement between previous methods and the adapted American College of Medical Genetics and Genomics and the Association for Molecular Pathology criteria. RESULTS: Agreement between the methods was 86.4% (K-alpha, 0.6). Application of the tailored guidelines resulted in an increased number of variants of uncertain significance (14.5% to 24.2%). Of the 85 variants that were downscaled to likely benign or variant of uncertain significance, 59.7% were missense variants outside a well-established functional site. Available clinical- or segregation data, necessary to further classify these types of variants, were in many cases insufficient to aid the classification. CONCLUSIONS: Our study shows that classification of variants remains challenging and may change over time. Currently, a higher level of evidence is necessary to classify a variant as pathogenic. Gene-specific guidelines may be useful to allow a more precise and uniform interpretation of the variants to accurately support clinical decision-making.

15.
Genet Med ; 20(9): 965-975, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29300384

RESUMO

PURPOSE: Mowat-Wilson syndrome (MWS) is a rare intellectual disability/multiple congenital anomalies syndrome caused by heterozygous mutation of the ZEB2 gene. It is generally underestimated because its rarity and phenotypic variability sometimes make it difficult to recognize. Here, we aimed to better delineate the phenotype, natural history, and genotype-phenotype correlations of MWS. METHODS: In a collaborative study, we analyzed clinical data for 87 patients with molecularly confirmed diagnosis. We described the prevalence of all clinical aspects, including attainment of neurodevelopmental milestones, and compared the data with the various types of underlying ZEB2 pathogenic variations. RESULTS: All anthropometric, somatic, and behavioral features reported here outline a variable but highly consistent phenotype. By presenting the most comprehensive evaluation of MWS to date, we define its clinical evolution occurring with age and derive suggestions for patient management. Furthermore, we observe that its severity correlates with the kind of ZEB2 variation involved, ranging from ZEB2 locus deletions, associated with severe phenotypes, to rare nonmissense intragenic mutations predicted to preserve some ZEB2 protein functionality, accompanying milder clinical presentations. CONCLUSION: Knowledge of the phenotypic spectrum of MWS and its correlation with the genotype will improve its detection rate and the prediction of its features, thus improving patient care.

16.
Ophthalmic Genet ; 39(2): 268-270, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29182461

RESUMO

BACKGROUND: To describe ocular and vascular findings in a patient with multiple endocrine neoplasia type 2B. MATERIALS AND METHODS: Case report of a 31-year-old male who was referred for ocular assessment following diagnosis of a carotid artery dissection and multiple vascular anomalies. RESULTS: Clinical examination revealed a marfanoid habitus, myelinated corneal nerve fibers, neuromas in the perilimbal area, conjunctival hyperemia with peripheral corneal neovascularization, and posterior blepharitis. Diagnosis of multiple endocrine neoplasia type 2B was confirmed by genetic testing of the RET proto-oncogene. Genetic screening for hereditary aortic and peripheral vasculopathies failed to reveal an underlying cause for the vascular findings. We noted improvement of the ocular surface disease with topical corticosteroids and oral tetracyclines. CONCLUSIONS: Ophthalmologists play a vital role in recognizing this rare but lethal malignancy. We report on a patient with apart from characteristic ocular findings also staphylococcal hypersensitivity and widespread systemic vasculopathy.

17.
Mol Genet Genomic Med ; 6(1): 15-26, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29150909

RESUMO

BACKGROUND: Osteogenesis imperfecta (OI) is a heterogeneous hereditary connective tissue disorder clinically hallmarked by increased susceptibility to bone fractures. METHODS: We analyzed a cohort of 77 diagnosed OI patients from 49 unrelated Palestinian families. Next-generation sequencing technology was used to screen a panel of known OI genes. RESULTS: In 41 probands, we identified 28 different disease-causing variants of 9 different known OI genes. Eleven of the variants are novel. Ten of the 28 variants are located in COL1A1, five in COL1A2, three in BMP1, three in FKBP10, two in TMEM38B, two in P3H1, and one each in CRTAP, SERPINF1, and SERPINH1. The absence of disease-causing variants in the remaining eight probands suggests further genetic heterogeneity in OI. In general, most OI patients (90%) harbor mainly variants in type I collagen resulting in an autosomal dominant inheritance pattern. However, in our cohort almost 61% (25/41) were affected with autosomal recessive OI. Moreover, we document a 21-kb genomic deletion in the TMEM38B gene identified in 29% (12/41) of the tested probands, making it the most frequent OI-causing variant in the Palestinian population. CONCLUSION: This is the first genetic screening of an OI cohort from the Palestinian population. Our data are important for genetic counseling of OI patients and families in highly consanguineous populations.


Assuntos
Árabes/genética , Osteogênese Imperfeita/genética , Adulto , Calcificação Fisiológica/genética , Colágeno Tipo I/genética , Consanguinidade , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Família , Feminino , Genes Recessivos , Humanos , Canais Iônicos/genética , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Deleção de Sequência
18.
Ophthalmic Genet ; 39(1): 29-34, 2018 Jan-Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28726533

RESUMO

INTRODUCTION: Arterial tortuosity syndrome (ATS) is a rare autosomal recessive disease hallmarked by tortuosity, stenosis, and aneurysm development of large- and medium-sized arteries. Mutations in SLC2A10, a gene that encodes the facilitative glucose transporter GLUT10, cause ATS. Several case reports have noted associated ophthalmic findings such as keratoconus, keratoglobus, and myopia without detailed descriptions or standardized examinations. We report the ophthalmic findings in a cohort of compound heterozygous ATS patients and heterozygous carriers of SLC2A10 mutations. METHODS: Five ATS patients and three carriers were identified through an ATS specialty clinic at the Arkansas Children's Hospital in Little Rock, Arkansas. Patients underwent complete eye examinations, including corneal pachymetry, topography, and optical coherence tomography when indicated. RESULTS: All five patients with ATS had myopia and thin corneas with an average central corneal thickness of 426 µm, and three had corneal ectasia, two with early keratoconus and one with keratoglobus and deep stromal corneal opacities. One patient had bilateral high irregular astigmatism, and one had unilateral high regular astigmatism. All carriers had myopia, one had corneal thinning, and one developed keratectasia in one eye many years after laser-assisted in situ keratomileusis (LASIK) surgery. CONCLUSION: We document a spectrum of ophthalmic manifestations of ATS with universal findings of myopia, corneal thinning, and a propensity for corneal ectasia leading to keratoconus or keratoglobus. Heterozygous carriers may develop keratectasia after corneal refractive surgery. Our data support regular eye examinations for all patients carrying SLC2A10 mutations with follow-up tailored to clinical findings.


Assuntos
Artérias/anormalidades , Córnea/patologia , Proteínas Facilitadoras de Transporte de Glucose/genética , Heterozigoto , Instabilidade Articular/diagnóstico , Ceratocone/diagnóstico , Mutação , Miopia/diagnóstico , Dermatopatias Genéticas/diagnóstico , Malformações Vasculares/diagnóstico , Adolescente , Adulto , Criança , Pré-Escolar , Paquimetria Corneana , Topografia da Córnea , Dilatação Patológica , Feminino , Humanos , Instabilidade Articular/genética , Ceratocone/genética , Masculino , Miopia/genética , Dermatopatias Genéticas/genética , Tomografia de Coerência Óptica , Malformações Vasculares/genética , Adulto Jovem
19.
Am J Hum Genet ; 101(6): 1021-1033, 2017 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-29220674

RESUMO

ACTB encodes ß-actin, an abundant cytoskeletal housekeeping protein. In humans, postulated gain-of-function missense mutations cause Baraitser-Winter syndrome (BRWS), characterized by intellectual disability, cortical malformations, coloboma, sensorineural deafness, and typical facial features. To date, the consequences of loss-of-function ACTB mutations have not been proven conclusively. We describe heterozygous ACTB deletions and nonsense and frameshift mutations in 33 individuals with developmental delay, apparent intellectual disability, increased frequency of internal organ malformations (including those of the heart and the renal tract), growth retardation, and a recognizable facial gestalt (interrupted wavy eyebrows, dense eyelashes, wide nose, wide mouth, and a prominent chin) that is distinct from characteristics of individuals with BRWS. Strikingly, this spectrum overlaps with that of several chromatin-remodeling developmental disorders. In wild-type mouse embryos, ß-actin expression was prominent in the kidney, heart, and brain. ACTB mRNA expression levels in lymphoblastic lines and fibroblasts derived from affected individuals were decreased in comparison to those in control cells. Fibroblasts derived from an affected individual and ACTB siRNA knockdown in wild-type fibroblasts showed altered cell shape and migration, consistent with known roles of cytoplasmic ß-actin. We also demonstrate that ACTB haploinsufficiency leads to reduced cell proliferation, altered expression of cell-cycle genes, and decreased amounts of nuclear, but not cytoplasmic, ß-actin. In conclusion, we show that heterozygous loss-of-function ACTB mutations cause a distinct pleiotropic malformation syndrome with intellectual disability. Our biological studies suggest that a critically reduced amount of this protein alters cell shape, migration, proliferation, and gene expression to the detriment of brain, heart, and kidney development.


Assuntos
Anormalidades Múltiplas/genética , Actinas/genética , Deficiências do Desenvolvimento/genética , Haploinsuficiência/genética , Actinas/biossíntese , Adolescente , Adulto , Idoso , Animais , Ciclo Celular/genética , Proliferação de Células/genética , Criança , Pré-Escolar , Códon sem Sentido/genética , Coloboma/genética , Facies , Feminino , Mutação da Fase de Leitura/genética , Deleção de Genes , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/genética , Masculino , Malformações do Desenvolvimento Cortical/genética , Camundongos , Interferência de RNA , RNA Interferente Pequeno/genética , Adulto Jovem
20.
Am J Med Genet A ; 173(11): 3104-3108, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28884947

RESUMO

We present a 4-year-old girl with delayed neuromotor development, short stature of prenatal onset, and specific behavioral and craniofacial features harboring an intragenic deletion in the ARID2 gene. The phenotype confirmed the major features of the recently described ARID2-related intellectual disability syndrome. However, our patient showed overlapping features with Nicolaides-Baraitser syndrome and Coffin-Siris syndrome, providing further arguments to reclassify these disorders as "SWI/SNF-related intellectual disability syndromes."


Assuntos
Proteínas Cromossômicas não Histona/genética , Deficiência Intelectual/genética , Transtornos Motores/genética , Fatores de Transcrição/genética , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Pré-Escolar , Face/anormalidades , Face/patologia , Facies , Feminino , Deformidades Congênitas do Pé/diagnóstico , Deformidades Congênitas do Pé/genética , Deformidades Congênitas do Pé/patologia , Predisposição Genética para Doença , Deformidades Congênitas da Mão/diagnóstico , Deformidades Congênitas da Mão/genética , Deformidades Congênitas da Mão/patologia , Humanos , Hipotricose/diagnóstico , Hipotricose/genética , Hipotricose/patologia , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/patologia , Deficiência Intelectual/fisiopatologia , Micrognatismo/diagnóstico , Micrognatismo/genética , Micrognatismo/patologia , Transtornos Motores/fisiopatologia , Pescoço/anormalidades , Pescoço/patologia
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