RESUMEN
Zinc and RING finger 3 (ZNRF3) is a negative-feedback regulator of Wnt/ß-catenin signaling, which plays an important role in human brain development. Although somatically frequently mutated in cancer, germline variants in ZNRF3 have not been established as causative for neurodevelopmental disorders (NDDs). We identified 12 individuals with ZNRF3 variants and various phenotypes via GeneMatcher/Decipher and evaluated genotype-phenotype correlation. We performed structural modeling and representative deleterious and control variants were assessed using in vitro transcriptional reporter assays with and without Wnt-ligand Wnt3a and/or Wnt-potentiator R-spondin (RSPO). Eight individuals harbored de novo missense variants and presented with NDD. We found missense variants associated with macrocephalic NDD to cluster in the RING ligase domain. Structural modeling predicted disruption of the ubiquitin ligase function likely compromising Wnt receptor turnover. Accordingly, the functional assays showed enhanced Wnt/ß-catenin signaling for these variants in a dominant negative manner. Contrarily, an individual with microcephalic NDD harbored a missense variant in the RSPO-binding domain predicted to disrupt binding affinity to RSPO and showed attenuated Wnt/ß-catenin signaling in the same assays. Additionally, four individuals harbored de novo truncating or de novo or inherited large in-frame deletion variants with non-NDD phenotypes, including heart, adrenal, or nephrotic problems. In contrast to NDD-associated missense variants, the effects on Wnt/ß-catenin signaling were comparable between the truncating variant and the empty vector and between benign variants and the wild type. In summary, we provide evidence for mirror brain size phenotypes caused by distinct pathomechanisms in Wnt/ß-catenin signaling through protein domain-specific deleterious ZNRF3 germline missense variants.
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Mutations that perturb normal pre-mRNA splicing are significant contributors to human disease. We used exome sequencing data from 7833 probands with developmental disorders (DDs) and their unaffected parents, as well as more than 60,000 aggregated exomes from the Exome Aggregation Consortium, to investigate selection around the splice sites and quantify the contribution of splicing mutations to DDs. Patterns of purifying selection, a deficit of variants in highly constrained genes in healthy subjects, and excess de novo mutations in patients highlighted particular positions within and around the consensus splice site of greater functional relevance. By using mutational burden analyses in this large cohort of proband-parent trios, we could estimate in an unbiased manner the relative contributions of mutations at canonical dinucleotides (73%) and flanking noncanonical positions (27%), and calculate the positive predictive value of pathogenicity for different classes of mutations. We identified 18 patients with likely diagnostic de novo mutations in dominant DD-associated genes at noncanonical positions in splice sites. We estimate 35%-40% of pathogenic variants in noncanonical splice site positions are missing from public databases.
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Discapacidades del Desarrollo/genética , Mutación , Sitios de Empalme de ARN , Exoma , Humanos , Secuenciación del ExomaRESUMEN
With advances in genetic testing and improved access to such advances, whole exome sequencing is becoming a first-line investigation in clinical work-up of children with developmental delay/intellectual disability (ID). As a result, the need to understand the importance of genetic variants and its effect on the clinical phenotype is increasing. Here, we report on the largest cohort of patients with HNRNPU variants. These 21 patients follow on from the previous study published by Yates et al. in 2017 from our group predominantly identified from the Deciphering Developmental Disorders study that reported seven patients with HNRNPU variants. All the probands reported here have a de novo loss-of-function variant. These probands have craniofacial dysmorphic features, in the majority including widely spaced teeth, microcephaly, high arched eyebrows, and palpebral fissure abnormalities. Many of the patients in the group also have moderate to severe ID and seizures that tend to start in early childhood. This series has allowed us to define a novel neurodevelopmental syndrome, with a likely mechanism of haploinsufficiency, and expand substantially on already published literature on HNRNPU-related neurodevelopmental syndrome.
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Ribonucleoproteína Heterogénea-Nuclear Grupo U/genética , Trastornos del Neurodesarrollo/etiología , Adolescente , Encéfalo/diagnóstico por imagen , Niño , Preescolar , Anomalías Craneofaciales/etiología , Femenino , Haploinsuficiencia/genética , Humanos , Lactante , Discapacidad Intelectual/genética , Masculino , Microcefalia/etiología , Trastornos del Neurodesarrollo/genética , Embarazo , Convulsiones/genética , SíndromeRESUMEN
Deletions at chromosome 2p25.3 are associated with a syndrome consisting of intellectual disability and obesity. The smallest region of overlap for deletions at 2p25.3 contains PXDN and MYT1L. MYT1L is expressed only within the brain in humans. We hypothesized that single nucleotide variants (SNVs) in MYT1L would cause a phenotype resembling deletion at 2p25.3. To examine this we sought MYT1L SNVs in exome sequencing data from 4, 296 parent-child trios. Further variants were identified through a genematcher-facilitated collaboration. We report 9 patients with MYT1L SNVs (4 loss of function and 5 missense). The phenotype of SNV carriers overlapped with that of 2p25.3 deletion carriers. To identify the transcriptomic consequences of MYT1L loss of function we used CRISPR-Cas9 to create a knockout cell line. Gene Ontology analysis in knockout cells demonstrated altered expression of genes that regulate gene expression and that are localized to the nucleus. These differentially expressed genes were enriched for OMIM disease ontology terms "mental retardation". To study the developmental effects of MYT1L loss of function we created a zebrafish knockdown using morpholinos. Knockdown zebrafish manifested loss of oxytocin expression in the preoptic neuroendocrine area. This study demonstrates that MYT1L variants are associated with syndromic obesity in humans. The mechanism is related to dysregulated expression of neurodevelopmental genes and altered development of the neuroendocrine hypothalamus.
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Regulación de la Expresión Génica/genética , Hipotálamo/fisiología , Discapacidad Intelectual/genética , Proteínas del Tejido Nervioso/genética , Obesidad/genética , Factores de Transcripción/genética , Adulto , Animales , Sistemas CRISPR-Cas , Línea Celular , Niño , Deleción Cromosómica , Cromosomas Humanos Par 2/genética , Femenino , Técnicas de Inactivación de Genes , Humanos , Hipotálamo/metabolismo , Hipotálamo/patología , Discapacidad Intelectual/fisiopatología , Masculino , Mutación , Obesidad/fisiopatología , Polimorfismo de Nucleótido Simple/genética , Pez CebraRESUMEN
BACKGROUND: De novo mutations in PURA have recently been described to cause PURA syndrome, a neurodevelopmental disorder characterised by severe intellectual disability (ID), epilepsy, feeding difficulties and neonatal hypotonia. OBJECTIVES: To delineate the clinical spectrum of PURA syndrome and study genotype-phenotype correlations. METHODS: Diagnostic or research-based exome or Sanger sequencing was performed in individuals with ID. We systematically collected clinical and mutation data on newly ascertained PURA syndrome individuals, evaluated data of previously reported individuals and performed a computational analysis of photographs. We classified mutations based on predicted effect using 3D in silico models of crystal structures of Drosophila-derived Pur-alpha homologues. Finally, we explored genotype-phenotype correlations by analysis of both recurrent mutations as well as mutation classes. RESULTS: We report mutations in PURA (purine-rich element binding protein A) in 32 individuals, the largest cohort described so far. Evaluation of clinical data, including 22 previously published cases, revealed that all have moderate to severe ID and neonatal-onset symptoms, including hypotonia (96%), respiratory problems (57%), feeding difficulties (77%), exaggerated startle response (44%), hypersomnolence (66%) and hypothermia (35%). Epilepsy (54%) and gastrointestinal (69%), ophthalmological (51%) and endocrine problems (42%) were observed frequently. Computational analysis of facial photographs showed subtle facial dysmorphism. No strong genotype-phenotype correlation was identified by subgrouping mutations into functional classes. CONCLUSION: We delineate the clinical spectrum of PURA syndrome with the identification of 32 additional individuals. The identification of one individual through targeted Sanger sequencing points towards the clinical recognisability of the syndrome. Genotype-phenotype analysis showed no significant correlation between mutation classes and disease severity.
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Proteínas de Unión al ADN/genética , Cara/anomalías , Discapacidad Intelectual/genética , Mutación , Factores de Transcripción/genética , Proteínas de Unión al ADN/química , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Anomalías del Ojo/genética , Femenino , Estudios de Asociación Genética , Humanos , Recién Nacido , Hipotonía Muscular/etiología , Hipotonía Muscular/genética , Embarazo , Homología Estructural de Proteína , Síndrome , Factores de Transcripción/químicaRESUMEN
Short stature, auditory canal atresia, mandibular hypoplasia, and skeletal abnormalities (SAMS) has been reported previously to be a rare, autosomal-recessive developmental disorder with other, unique rhizomelic skeletal anomalies. These include bilateral humeral hypoplasia, humeroscapular synostosis, pelvic abnormalities, and proximal defects of the femora. To identify the genetic basis of SAMS, we used molecular karyotyping and whole-exome sequencing (WES) to study small, unrelated families. Filtering of variants from the WES data included segregation analysis followed by comparison of in-house exomes. We identified a homozygous 306 kb microdeletion and homozygous predicted null mutations of GSC, encoding Goosecoid homeobox protein, a paired-like homeodomain transcription factor. This confirms that SAMS is a human malformation syndrome resulting from GSC mutations. Previously, Goosecoid has been shown to be a determinant at the Xenopus gastrula organizer region and a segment-polarity determinant in Drosophila. In the present report, we present data on Goosecoid protein localization in staged mouse embryos. These data and the SAMS clinical phenotype both suggest that Goosecoid is a downstream effector of the regulatory networks that define neural-crest cell-fate specification and subsequent mesoderm cell lineages in mammals, particularly during shoulder and hip formation. Our findings confirm that Goosecoid has an essential role in human craniofacial and joint development and suggest that Goosecoid is an essential regulator of mesodermal patterning in mammals and that it has specific functions in neural crest cell derivatives.
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Anomalías Múltiples/genética , Huesos/anomalías , Enanismo/genética , Conducto Auditivo Externo/anomalías , Proteína Goosecoide/genética , Mandíbula/anomalías , Mutación , Anomalías Múltiples/diagnóstico , Adulto , Animales , Niño , Análisis Mutacional de ADN , Femenino , Estudios de Asociación Genética , Homocigoto , Humanos , Masculino , Ratones , Linaje , Fenotipo , Síndrome , Adulto JovenRESUMEN
BACKGROUND: Anophthalmia, microphthalmia and coloboma are a genetically heterogenous spectrum of developmental eye disorders. Recently, variants in the Wnt-pathway gene Frizzled Class Receptor 5 (FZD5) have been identified in individuals with coloboma and rarely microphthalmia, sometimes with additional phenotypes and variable penetrance. MATERIALS AND METHODS: We identified variants in FZD5 in individuals with developmental eye disorders from the UK (including the DDD Study [www.ddduk.org/access.html]), France and Spain using whole genome/exome sequencing or customized NGS panels of ocular development genes. RESULTS: We report eight new families with FZD5 variants and ocular coloboma. Three individuals presented with additional syndromic features, two explicable by additional variants in other genes (SLC12A2 and DDX3X). In two families initially showing incomplete penetrance, re-examination of apparently unaffected carrier individuals revealed subtle ocular colobomatous phenotypes. Finally, we report two families with microphthalmia in addition to coloboma, representing the second and third reported cases of this phenotype in conjunction with FZD5 variants. CONCLUSIONS: Our findings indicate FZD5 variants are typically associated with isolated ocular coloboma, occasionally microphthalmia, and that extraocular phenotypes are likely to be explained by other gene alterations.
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Anoftalmos , Coloboma , Microftalmía , Humanos , Microftalmía/genética , Coloboma/diagnóstico , Coloboma/genética , Ojo , Anoftalmos/genética , Fenotipo , Receptores Frizzled/genética , Miembro 2 de la Familia de Transportadores de Soluto 12/genéticaRESUMEN
BACKGROUND AND OBJECTIVES: ATP1A3 is associated with a broad spectrum of predominantly neurologic disorders, which continues to expand beyond the initially defined phenotypes of alternating hemiplegia of childhood, rapid-onset dystonia parkinsonism, and cerebellar ataxia, areflexia, pes cavus, optic atrophy, sensorineural hearing loss syndrome. This phenotypic variability makes it challenging to assess the pathogenicity of an ATP1A3 variant found in an undiagnosed patient. We describe the phenotypic features of individuals carrying a pathogenic/likely pathogenic ATP1A3 variant and perform a literature review of all ATP1A3 variants published thus far in association with human neurologic disease. Our aim is to demonstrate the heterogeneous clinical spectrum of the gene and look for phenotypic overlap between patients that will streamline the diagnostic process. METHODS: Undiagnosed individuals with ATP1A3 variants were identified within the cohort of the Deciphering Developmental Disorders study with additional cases contributed by collaborators internationally. Detailed clinical data were collected with consent through a questionnaire completed by the referring clinicians. PubMed was searched for publications containing the term "ATP1A3" from 2004 to 2021. RESULTS: Twenty-four individuals with a previously undiagnosed neurologic phenotype were found to carry 21 ATP1A3 variants. Eight variants have been previously published. Patients experienced on average 2-3 different types of paroxysmal events. Permanent neurologic features were common including microcephaly (7; 29%), ataxia (13; 54%), dystonia (10; 42%), and hypotonia (7; 29%). All patients had cognitive impairment. Neuropsychiatric diagnoses were reported in 16 (66.6%) individuals. Phenotypes were extremely varied, and most individuals did not fit clinical criteria for previously published phenotypes. On review of the literature, 1,108 individuals have been reported carrying 168 different ATP1A3 variants. The most common variants are associated with well-defined phenotypes, while more rare variants often result in very rare symptom correlations, such as are seen in our study. Combined Annotation-Dependent Depletion (CADD) scores of pathogenic and likely pathogenic variants were significantly higher and variants clustered within 6 regions of constraint. DISCUSSION: Our study shows that looking for a combination of paroxysmal events, hyperkinesia, neuropsychiatric symptoms, and cognitive impairment and evaluating the CADD score and variant location can help identify an ATP1A3-related condition, rather than applying diagnostic criteria alone.
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Ataxia Cerebelosa , Trastornos Distónicos , Ataxia Cerebelosa/genética , Trastornos Distónicos/genética , Hemiplejía/genética , Humanos , Mutación/genética , Fenotipo , ATPasa Intercambiadora de Sodio-Potasio/genéticaRESUMEN
The HSPs (hereditary spastic paraplegias) are genetic conditions in which there is distal degeneration of the longest axons of the corticospinal tract, resulting in spastic paralysis of the legs. The gene encoding spartin is mutated in Troyer syndrome, an HSP in which paralysis is accompanied by additional clinical features. There has been controversy over the subcellular distribution of spartin. We show here that, at steady state, endogenous spartin exists in a cytosolic pool that can be recruited to endosomes and to lipid droplets. Cytosolic endogenous spartin is mono-ubiquitinated and we demonstrate that it interacts via a PPXY motif with the ubiquitin E3 ligases AIP4 [atrophin-interacting protein 4; ITCH (itchy E3 ubiquitin protein ligase homologue] [corrected] and AIP5 (WWP1). Surprisingly, the PPXY motif, AIP4 and AIP5 are not required for spartin's ubiquitination, and so we propose that spartin acts as an adaptor for these proteins. Our results suggest that spartin is involved in diverse cellular functions, which may be of relevance to the complex phenotype seen in Troyer syndrome.
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Endosomas/metabolismo , Metabolismo de los Lípidos , Proteínas/metabolismo , Proteínas Represoras/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Proteínas de Ciclo Celular , Células HeLa , Humanos , Metabolismo de los Lípidos/fisiología , Liposomas/metabolismo , Ratones , Células PC12 , Unión Proteica , Ratas , Células Tumorales Cultivadas , UbiquitinaciónRESUMEN
A 52-year-old man was found to have a severely dilated aortic root and a Stanford type A dissection on familial screening echocardiography, following diagnosis of a dilated aorta in his son. The dissection required urgent surgical repair. Clinical examination suggested features of Loeys-Dietz syndrome type II, and subsequent demonstration of a mutation in the TGFBR1 gene in the patient and his son confirmed the diagnosis. This article highlights the high prevalence of inherited conditions in dilated aortic root presentations and the importance of family screening and surveillance to allow early surgical intervention.
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Síndrome de Loeys-Dietz/diagnóstico , Diagnóstico Diferencial , Ecocardiografía , Humanos , Síndrome de Loeys-Dietz/genética , Síndrome de Loeys-Dietz/cirugía , Masculino , Persona de Mediana Edad , Mutación , Linaje , Proteínas Serina-Treonina Quinasas/genética , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/genética , Tomografía Computarizada por Rayos XRESUMEN
In this review we focus on Charcot-Marie-Tooth (CMT) neuropathies and hereditary spastic paraplegias (HSPs). Although these diseases differ in whether they primarily affect the peripheral or central nervous system, both are genetically determined, progressive, long axonopathies that affect motor and sensory pathways. This commonality suggests that there might be similarities in the molecular pathology underlying these conditions, and here we compare the molecular genetics and cellular pathology of the two groups.
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Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/patología , Paraplejía Espástica Hereditaria/genética , Paraplejía Espástica Hereditaria/patología , Animales , Enfermedad de Charcot-Marie-Tooth/epidemiología , Humanos , Mutación/genética , Fibras Nerviosas Mielínicas/patología , Paraplejía Espástica Hereditaria/epidemiologíaRESUMEN
Controversy surrounds the use of PSA as a biomarker for prostate cancer detection, leaving an unmet need for a novel biomarker in this setting; urinary EN2 may identify individuals with clinically relevant prostate cancer. Male BRCA1 and BRCA2 mutation carriers are at increased risk of clinically significant prostate cancer and may benefit from screening. Urine samples from 413 BRCA1 and BRCA2 mutation carriers and controls were evaluated. Subjects underwent annual PSA screening with diagnostic biopsy triggered by PSA > 3.0â ng/ml; 21 men were diagnosed with prostate cancer. Urinary EN2 levels were measured by ELISA and had a sensitivity of 66.7% and specificity of 89.3% for cancer detection. There was no statistically significant difference in EN2 levels according to genetic status or Gleason score. Urinary EN2 may be useful as a non-invasive early biomarker for prostate cancer detection in genetically high-risk individuals.
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Biomarcadores de Tumor/orina , Proteínas de Homeodominio/orina , Proteínas del Tejido Nervioso/orina , Neoplasias de la Próstata/diagnóstico , Adulto , Anciano , Genes BRCA1 , Genes BRCA2 , Humanos , Masculino , Persona de Mediana Edad , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/genéticaRESUMEN
BACKGROUND: Microseminoprotein-beta (MSMB) regulates apoptosis and using genome-wide association studies the rs10993994 single nucleotide polymorphism in the MSMB promoter has been linked to an increased risk of developing prostate cancer. The promoter location of the risk allele, and its ability to reduce promoter activity, suggested that the rs10993994 risk allele could result in lowered MSMB in benign tissue leading to increased prostate cancer risk. METHODOLOGY/PRINCIPAL FINDINGS: MSMB expression in benign and malignant prostate tissue was examined using immunohistochemistry and compared with the rs10993994 genotype. Urinary MSMB concentrations were determined by ELISA and correlated with urinary PSA, the presence or absence of cancer, rs10993994 genotype and age of onset. MSMB levels in prostate tissue and urine were greatly reduced with tumourigenesis. Urinary MSMB was better than urinary PSA at differentiating men with prostate cancer at all Gleason grades. The high risk allele was associated with heterogeneity of MSMB staining and loss of MSMB in both tissue and urine in benign prostate. CONCLUSIONS: These data show that some high risk alleles discovered using genome-wide association studies produce phenotypic effects with potential clinical utility. We provide the first link between a low penetrance polymorphism for prostate cancer and a potential test in human tissue and bodily fluids. There is potential to develop tissue and urinary MSMB for a biomarker of prostate cancer risk, diagnosis and disease monitoring.