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DExD/H-box RNA helicases (DDX/DHX) are encoded by a large paralogous gene family; in a subset of these human helicase genes, pathogenic variation causes neurodevelopmental disorder (NDD) traits and cancer. DHX9 encodes a BRCA1-interacting nuclear helicase regulating transcription, R-loops, and homologous recombination and exhibits the highest mutational constraint of all DDX/DHX paralogs but remains unassociated with disease traits in OMIM. Using exome sequencing and family-based rare-variant analyses, we identified 20 individuals with de novo, ultra-rare, heterozygous missense or loss-of-function (LoF) DHX9 variant alleles. Phenotypes ranged from NDDs to the distal symmetric polyneuropathy axonal Charcot-Marie-Tooth disease (CMT2). Quantitative Human Phenotype Ontology (HPO) analysis demonstrated genotype-phenotype correlations with LoF variants causing mild NDD phenotypes and nuclear localization signal (NLS) missense variants causing severe NDD. We investigated DHX9 variant-associated cellular phenotypes in human cell lines. Whereas wild-type DHX9 was restricted to the nucleus, NLS missense variants abnormally accumulated in the cytoplasm. Fibroblasts from an individual with an NLS variant also showed abnormal cytoplasmic DHX9 accumulation. CMT2-associated missense variants caused aberrant nucleolar DHX9 accumulation, a phenomenon previously associated with cellular stress. Two NDD-associated variants, p.Gly411Glu and p.Arg761Gln, altered DHX9 ATPase activity. The severe NDD-associated variant p.Arg141Gln did not affect DHX9 localization but instead increased R-loop levels and double-stranded DNA breaks. Dhx9-/- mice exhibited hypoactivity in novel environments, tremor, and sensorineural hearing loss. All together, these results establish DHX9 as a critical regulator of mammalian neurodevelopment and neuronal homeostasis.
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Enfermedad de Charcot-Marie-Tooth , Trastornos del Neurodesarrollo , Animales , Humanos , Ratones , Línea Celular , Enfermedad de Charcot-Marie-Tooth/genética , ARN Helicasas DEAD-box/genética , Diclorodifenil Dicloroetileno , ADN Helicasas , Mamíferos , Proteínas de Neoplasias/genéticaRESUMEN
Exome sequencing (ES) and genome sequencing (GS) have radically transformed the diagnostic approach to undiagnosed rare/ultrarare Mendelian diseases. Next-generation sequencing (NGS), the technology integral for ES, GS, and most large (100+) gene panels, has enabled previously unimaginable diagnoses, changes in medical management, new treatments, and accurate reproductive risk assessments for patients, as well as new disease gene discoveries. Yet, challenges remain, as most individuals remain undiagnosed with current NGS. Improved NGS technology has resulted in long-read sequencing, which may resolve diagnoses in some patients who do not obtain a diagnosis with current short-read ES and GS, but its effectiveness is unclear, and it is expensive. Other challenges that persist include the resolution of variants of uncertain significance, the urgent need for patients with ultrarare disorders to have access to therapeutics, the need for equity in patient access to NGS-based testing, and the study of ethical concerns. However, the outlook for undiagnosed disease resolution is bright, due to continual advancements in the field.
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Exoma , Enfermedades Raras , Humanos , Secuenciación del Exoma , Exoma/genética , Enfermedades Raras/diagnóstico , Enfermedades Raras/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Pruebas Genéticas/métodosRESUMEN
Au-Kline syndrome (AKS) is a neurodevelopmental disorder associated with multiple malformations and a characteristic facial gestalt. The first individuals ascertained carried de novo loss-of-function (LoF) variants in HNRNPK. Here, we report 32 individuals with AKS (26 previously unpublished), including 13 with de novo missense variants. We propose new clinical diagnostic criteria for AKS that differentiate it from the clinically overlapping Kabuki syndrome and describe a significant phenotypic expansion to include individuals with missense variants who present with subtle facial features and few or no malformations. Many gene-specific DNA methylation (DNAm) signatures have been identified for neurodevelopmental syndromes. Because HNRNPK has roles in chromatin and epigenetic regulation, we hypothesized that pathogenic variants in HNRNPK may be associated with a specific DNAm signature. Here, we report a unique DNAm signature for AKS due to LoF HNRNPK variants, distinct from controls and Kabuki syndrome. This DNAm signature is also identified in some individuals with de novo HNRNPK missense variants, confirming their pathogenicity and the phenotypic expansion of AKS to include more subtle phenotypes. Furthermore, we report that some individuals with missense variants have an "intermediate" DNAm signature that parallels their milder clinical presentation, suggesting the presence of an epi-genotype phenotype correlation. In summary, the AKS DNAm signature may help elucidate the underlying pathophysiology of AKS. This DNAm signature also effectively supported clinical syndrome delineation and is a valuable aid for variant interpretation in individuals where a clinical diagnosis of AKS is unclear, particularly for mild presentations.
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Metilación de ADN , Discapacidad Intelectual , Anomalías Múltiples , Cromatina , Metilación de ADN/genética , Epigénesis Genética , Cara/anomalías , Enfermedades Hematológicas , Ribonucleoproteína Heterogénea-Nuclear Grupo K/genética , Humanos , Discapacidad Intelectual/genética , Fenotipo , Enfermedades VestibularesRESUMEN
Genomic medicine has been transformed by next-generation sequencing (NGS), inclusive of exome sequencing (ES) and genome sequencing (GS). Currently, ES is offered widely in clinical settings, with a less prevalent alternative model consisting of hybrid programs that incorporate research ES along with clinical patient workflows. We were among the earliest to implement a hybrid ES clinic, have provided diagnoses to 45% of probands, and have identified several novel candidate genes. Our program is enabled by a cost-effective investment by the health system and is unique in encompassing all the processes that have been variably included in other hybrid/clinical programs. These include careful patient selection, utilization of a phenotype-agnostic bioinformatics pipeline followed by manual curation of variants and phenotype integration by clinicians, close collaborations between the clinicians and the bioinformatician, pursuit of interesting variants, communication of results to patients in categories that are predicated upon the certainty of a diagnosis, and tracking changes in results over time and the underlying mechanisms for such changes. Due to its effectiveness, scalability to GS and its resource efficiency, specific elements of our paradigm can be incorporated into existing clinical settings, or the entire hybrid model can be implemented within health systems that have genomic medicine programs, to provide NGS in a scientifically rigorous, yet pragmatic setting.
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Biología Computacional , Exoma , Humanos , Exoma/genética , Fenotipo , Secuenciación del Exoma , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
Sphingolipids are a diverse family of lipids with critical structural and signalling functions in the mammalian nervous system, where they are abundant in myelin membranes. Serine palmitoyltransferase, the enzyme that catalyses the rate-limiting reaction of sphingolipid synthesis, is composed of multiple subunits including an activating subunit, SPTSSA. Sphingolipids are both essential and cytotoxic and their synthesis must therefore be tightly regulated. Key to the homeostatic regulation are the ORMDL proteins that are bound to serine palmitoyltransferase and mediate feedback inhibition of enzymatic activity when sphingolipid levels become excessive. Exome sequencing identified potential disease-causing variants in SPTSSA in three children presenting with a complex form of hereditary spastic paraplegia. The effect of these variants on the catalytic activity and homeostatic regulation of serine palmitoyltransferase was investigated in human embryonic kidney cells, patient fibroblasts and Drosophila. Our results showed that two different pathogenic variants in SPTSSA caused a hereditary spastic paraplegia resulting in progressive motor disturbance with variable sensorineural hearing loss and language/cognitive dysfunction in three individuals. The variants in SPTSSA impaired the negative regulation of serine palmitoyltransferase by ORMDLs leading to excessive sphingolipid synthesis based on biochemical studies and in vivo studies in Drosophila. These findings support the pathogenicity of the SPTSSA variants and point to excessive sphingolipid synthesis due to impaired homeostatic regulation of serine palmitoyltransferase as responsible for defects in early brain development and function.
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Paraplejía Espástica Hereditaria , Animales , Niño , Humanos , Paraplejía Espástica Hereditaria/genética , Serina C-Palmitoiltransferasa/genética , Serina C-Palmitoiltransferasa/metabolismo , Esfingolípidos/metabolismo , Membrana Celular/metabolismo , Mamíferos/metabolismoRESUMEN
PURPOSE: Next-generation sequencing (NGS) has revolutionized the diagnostic process for rare/ultrarare conditions. However, diagnosis rates differ between analytical pipelines. In the National Institutes of Health-Undiagnosed Diseases Network (UDN) study, each individual's NGS data are concurrently analyzed by the UDN sequencing core laboratory and the clinical sites. We examined the outcomes of this practice. METHODS: A retrospective review was performed at 2 UDN clinical sites to compare the variants and diagnoses/candidate genes identified with the dual analyses of the NGS data. RESULTS: In total, 95 individuals had 100 diagnoses/candidate genes. There was 59% concordance between the UDN sequencing core laboratories and the clinical sites in identifying diagnoses/candidate genes. The core laboratory provided more diagnoses, whereas the clinical sites prioritized more research variants/candidate genes (P < .001). The clinical sites solely identified 15% of the diagnoses/candidate genes. The differences between the 2 pipelines were more often because of variant prioritization disparities than variant detection. CONCLUSION: The unique dual analysis of NGS data in the UDN synergistically enhances outcomes. The core laboratory provided a clinical analysis with more diagnoses and the clinical sites prioritized more research variants/candidate genes. Implementing such concurrent dual analyses in other genomic research studies and clinical settings can improve both variant detection and prioritization.
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Enfermedades no Diagnosticadas , Estados Unidos/epidemiología , Humanos , Genómica , Enfermedades Raras/diagnóstico , Enfermedades Raras/genética , Secuenciación de Nucleótidos de Alto Rendimiento , LaboratoriosRESUMEN
BACKGROUND: Children with congenital heart disease (CHD) are at risk for neurodevelopmental deficits. This study aimed to investigate the impact of cognitive deficits on educational outcome and participation in leisure activities. METHODS: A prospective cohort of 134 children with CHD who underwent cardiopulmonary bypass surgery (CPB) was examined at 10 years of age. IQ was assessed with the WISC-IV and executive functions with the BRIEF (parent- and teacher-report). Parents reported on type and level of education and educational support, and leisure activity participation. Ordinal regression analyses assessed the association between cognitive deficits and educational outcome and participation. RESULTS: Total IQ (P = 0.023), working memory (P < 0.001), processing speed (P = 0.008), and teacher-reported metacognition (P = 0.022) were lower than norms. Regular school was attended by 82.4% of children with CHD compared to 97% of the general Swiss population (P < 0.001). Seventy-five percent of children participated in leisure activities. Lower total IQ and teacher-rated global executive functions were associated with more educational support and lower IQ was associated with less participation. CONCLUSION: As school-aged children with CHD experience cognitive deficits, follow-up is required to provide optimal support with regard to educational outcome and participation in leisure activities. IMPACT: Contemporary cohorts of children with congenital heart disease undergoing cardiopulmonary bypass surgery remain at increased risk for cognitive deficits. Cognitive deficits affect educational outcome and leisure activities. These findings underline the importance of early detection of cognitive deficits and recommend support with respect to cognitive functioning.
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Cognición , Cardiopatías Congénitas , Niño , Humanos , Estudios Prospectivos , Escolaridad , Cardiopatías Congénitas/complicaciones , Cardiopatías Congénitas/cirugía , Cardiopatías Congénitas/diagnóstico , Actividades RecreativasRESUMEN
Although genomic research offering next-generation sequencing (NGS) has increased the diagnoses of rare/ultra-rare disorders, populations experiencing health disparities infrequently participate in these studies. The factors underlying non-participation would most reliably be ascertained from individuals who have had the opportunity to participate, but decline. We thus enrolled parents of children and adult probands with undiagnosed disorders who had declined genomic research offering NGS with return of results with undiagnosed disorders (Decliners, n = 21) and compared their data to those who participated (Participants, n = 31). We assessed: (1) practical barriers and facilitators, (2) sociocultural factors-genomic knowledge and distrust, and (3) the value placed upon a diagnosis by those who declined participation. The primary findings were that residence in rural and medically underserved areas (MUA) and higher number of barriers were significantly associated with declining participation in the study. Exploratory analyses revealed multiple co-occurring practical barriers, greater emotional exhaustion and research hesitancy in the parents in the Decliner group compared to the Participants, with both groups identifying a similar number of facilitators. The parents in the Decliner group also had lower genomic knowledge, but distrust of clinical research was not different between the groups. Importantly, despite their non-participation, those in the Decliner group indicated an interest in obtaining a diagnosis and expressed confidence in being able to emotionally manage the ensuing results. Study findings support the concept that some families who decline participation in diagnostic genomic research may be experiencing pile-up with exhaustion of family resources - making participation in the genomic research difficult. This study highlights the complexity of the factors that underlie non-participation in clinically relevant NGS research. Thus, approaches to mitigating barriers to NGS research participation by populations experiencing health disparities need to be multi-pronged and tailored so that they can benefit from state-of -the art genomic technologies.
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Genómica , Padres , Adulto , Niño , Humanos , Padres/psicologíaRESUMEN
SMARCC2 (BAF170) is one of the invariable core subunits of the ATP-dependent chromatin remodeling BAF (BRG1-associated factor) complex and plays a crucial role in embryogenesis and corticogenesis. Pathogenic variants in genes encoding other components of the BAF complex have been associated with intellectual disability syndromes. Despite its significant biological role, variants in SMARCC2 have not been directly associated with human disease previously. Using whole-exome sequencing and a web-based gene-matching program, we identified 15 individuals with variable degrees of neurodevelopmental delay and growth retardation harboring one of 13 heterozygous variants in SMARCC2, most of them novel and proven de novo. The clinical presentation overlaps with intellectual disability syndromes associated with other BAF subunits, such as Coffin-Siris and Nicolaides-Baraitser syndromes and includes prominent speech impairment, hypotonia, feeding difficulties, behavioral abnormalities, and dysmorphic features such as hypertrichosis, thick eyebrows, thin upper lip vermilion, and upturned nose. Nine out of the fifteen individuals harbor variants in the highly conserved SMARCC2 DNA-interacting domains (SANT and SWIRM) and present with a more severe phenotype. Two of these individuals present cardiac abnormalities. Transcriptomic analysis of fibroblasts from affected individuals highlights a group of differentially expressed genes with possible roles in regulation of neuronal development and function, namely H19, SCRG1, RELN, and CACNB4. Our findings suggest a novel SMARCC2-related syndrome that overlaps with neurodevelopmental disorders associated with variants in BAF-complex subunits.
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Discapacidades del Desarrollo/complicaciones , Discapacidades del Desarrollo/genética , Discapacidad Intelectual/complicaciones , Discapacidad Intelectual/genética , Mutación , Factores de Transcripción/genética , Anomalías Múltiples/genética , Adolescente , Niño , Preescolar , Proteínas de Unión al ADN , Cara/anomalías , Femenino , Deformidades Congénitas de la Mano/genética , Humanos , Masculino , Micrognatismo/genética , Cuello/anomalías , Proteína Reelina , SíndromeRESUMEN
The Genome Empowerment Scale (GEmS), developed as a research tool, assesses perspectives of parents of children with undiagnosed disorders about to undergo exome or genome sequencing related to the process of empowerment. We defined genomic healthcare empowerment as follows: perceived ability to understand and seek new information related to the genomic sequencing, manage emotions related to the diagnostic process and outcomes, and utilize genomic sequencing information to the betterment of the individual/child and family. The GEmS consists of four scales, two are primarily emotion-focused (Meaning of a Diagnosis, and Emotional Management of the Process) and two are action-oriented (Seeking Information and Support, and Implications and Planning). The purpose of this research was to provide a strategy for interpreting results from the GEmS and present illustrative cases. These illustrations should serve to facilitate use of the GEmS in the clinical and research arena, particularly with respect to guiding genetic counseling processes for parents of children with undiagnosed conditions.
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Genómica , Padres , Niño , Atención a la Salud , Familia , Humanos , Padres/psicología , Secuenciación del ExomaRESUMEN
Interferon regulatory factor 2 binding protein-like (IRF2BPL) encodes a member of the IRF2BP family of transcriptional regulators. Currently the biological function of this gene is obscure, and the gene has not been associated with a Mendelian disease. Here we describe seven individuals who carry damaging heterozygous variants in IRF2BPL and are affected with neurological symptoms. Five individuals who carry IRF2BPL nonsense variants resulting in a premature stop codon display severe neurodevelopmental regression, hypotonia, progressive ataxia, seizures, and a lack of coordination. Two additional individuals, both with missense variants, display global developmental delay and seizures and a relatively milder phenotype than those with nonsense alleles. The IRF2BPL bioinformatics signature based on population genomics is consistent with a gene that is intolerant to variation. We show that the fruit-fly IRF2BPL ortholog, called pits (protein interacting with Ttk69 and Sin3A), is broadly detected, including in the nervous system. Complete loss of pits is lethal early in development, whereas partial knockdown with RNA interference in neurons leads to neurodegeneration, revealing a requirement for this gene in proper neuronal function and maintenance. The identified IRF2BPL nonsense variants behave as severe loss-of-function alleles in this model organism, and ectopic expression of the missense variants leads to a range of phenotypes. Taken together, our results show that IRF2BPL and pits are required in the nervous system in humans and flies, and their loss leads to a range of neurological phenotypes in both species.
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PURPOSE: The NIH Undiagnosed Diseases Network (UDN) evaluates participants with disorders that have defied diagnosis, applying personalized clinical and genomic evaluations and innovative research. The clinical sites of the UDN are essential to advancing the UDN mission; this study assesses their contributions relative to standard clinical practices. METHODS: We analyzed retrospective data from four UDN clinical sites, from July 2015 to September 2019, for diagnoses, new disease gene discoveries and the underlying investigative methods. RESULTS: Of 791 evaluated individuals, 231 received 240 diagnoses and 17 new disease-gene associations were recognized. Straightforward diagnoses on UDN exome and genome sequencing occurred in 35% (84/240). We considered these tractable in standard clinical practice, although genome sequencing is not yet widely available clinically. The majority (156/240, 65%) required additional UDN-driven investigations, including 90 diagnoses that occurred after prior nondiagnostic exome sequencing and 45 diagnoses (19%) that were nongenetic. The UDN-driven investigations included complementary/supplementary phenotyping, innovative analyses of genomic variants, and collaborative science for functional assays and animal modeling. CONCLUSION: Investigations driven by the clinical sites identified diagnostic and research paradigms that surpass standard diagnostic processes. The new diagnoses, disease gene discoveries, and delineation of novel disorders represent a model for genomic medicine and science.
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Enfermedades no Diagnosticadas , Animales , Genómica , Humanos , Enfermedades Raras/diagnóstico , Enfermedades Raras/genética , Estudios Retrospectivos , Secuenciación del ExomaRESUMEN
PURPOSE: CACNA1C encodes the alpha-1-subunit of a voltage-dependent L-type calcium channel expressed in human heart and brain. Heterozygous variants in CACNA1C have previously been reported in association with Timothy syndrome and long QT syndrome. Several case reports have suggested that CACNA1C variation may also be associated with a primarily neurological phenotype. METHODS: We describe 25 individuals from 22 families with heterozygous variants in CACNA1C, who present with predominantly neurological manifestations. RESULTS: Fourteen individuals have de novo, nontruncating variants and present variably with developmental delays, intellectual disability, autism, hypotonia, ataxia, and epilepsy. Functional studies of a subgroup of missense variants via patch clamp experiments demonstrated differential effects on channel function in vitro, including loss of function (p.Leu1408Val), neutral effect (p.Leu614Arg), and gain of function (p.Leu657Phe, p.Leu614Pro). The remaining 11 individuals from eight families have truncating variants in CACNA1C. The majority of these individuals have expressive language deficits, and half have autism. CONCLUSION: We expand the phenotype associated with CACNA1C variants to include neurodevelopmental abnormalities and epilepsy, in the absence of classic features of Timothy syndrome or long QT syndrome.
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Trastorno Autístico , Canales de Calcio Tipo L , Síndrome de QT Prolongado , Sindactilia , Trastorno Autístico/genética , Canales de Calcio Tipo L/genética , Humanos , FenotipoRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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PURPOSE: Determination of genotypic/phenotypic features of GATAD2B-associated neurodevelopmental disorder (GAND). METHODS: Fifty GAND subjects were evaluated to determine consistent genotypic/phenotypic features. Immunoprecipitation assays utilizing in vitro transcription-translation products were used to evaluate GATAD2B missense variants' ability to interact with binding partners within the nucleosome remodeling and deacetylase (NuRD) complex. RESULTS: Subjects had clinical findings that included macrocephaly, hypotonia, intellectual disability, neonatal feeding issues, polyhydramnios, apraxia of speech, epilepsy, and bicuspid aortic valves. Forty-one novelGATAD2B variants were identified with multiple variant types (nonsense, truncating frameshift, splice-site variants, deletions, and missense). Seven subjects were identified with missense variants that localized within two conserved region domains (CR1 or CR2) of the GATAD2B protein. Immunoprecipitation assays revealed several of these missense variants disrupted GATAD2B interactions with its NuRD complex binding partners. CONCLUSIONS: A consistent GAND phenotype was caused by a range of genetic variants in GATAD2B that include loss-of-function and missense subtypes. Missense variants were present in conserved region domains that disrupted assembly of NuRD complex proteins. GAND's clinical phenotype had substantial clinical overlap with other disorders associated with the NuRD complex that involve CHD3 and CHD4, with clinical features of hypotonia, intellectual disability, cardiac defects, childhood apraxia of speech, and macrocephaly.
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Discapacidad Intelectual , Megalencefalia , Trastornos del Neurodesarrollo , Niño , Femenino , Factores de Transcripción GATA/genética , Humanos , Discapacidad Intelectual/genética , Trastornos del Neurodesarrollo/genética , Nucleosomas , Fenotipo , Embarazo , Proteínas RepresorasRESUMEN
Pathogenic variants in KMT2D, which encodes lysine specific methyltransferase 2D, cause autosomal dominant Kabuki syndrome, associated with distinctive dysmorphic features including arched eyebrows, long palpebral fissures with eversion of the lower lid, large protuberant ears, and fetal finger pads. Most disease-causing variants identified to date are putative loss-of-function alleles, although 15-20% of cases are attributed to missense variants. We describe here four patients (including one previously published patient) with de novo KMT2D missense variants and with shared but unusual clinical findings not typically seen in Kabuki syndrome, including athelia (absent nipples), choanal atresia, hypoparathyroidism, delayed or absent pubertal development, and extreme short stature. These individuals also lack the typical dysmorphic facial features found in Kabuki syndrome. Two of the four patients had severe interstitial lung disease. All of these variants cluster within a 40-amino-acid region of the protein that is located just N-terminal of an annotated coiled coil domain. These findings significantly expand the phenotypic spectrum of features associated with variants in KMT2D beyond those seen in Kabuki syndrome and suggest a possible new underlying disease mechanism for these patients.
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Anomalías Múltiples/genética , Mama/anomalías , Anomalías Congénitas/genética , Proteínas de Unión al ADN/genética , Cara/anomalías , Predisposición Genética a la Enfermedad , Enfermedades Hematológicas/genética , Proteínas de Neoplasias/genética , Enfermedades Vestibulares/genética , Anomalías Múltiples/diagnóstico por imagen , Anomalías Múltiples/patología , Adolescente , Adulto , Mama/diagnóstico por imagen , Mama/fisiopatología , Enfermedades de la Mama , Niño , Anomalías Congénitas/diagnóstico por imagen , Anomalías Congénitas/fisiopatología , Cara/diagnóstico por imagen , Cara/patología , Femenino , Enfermedades Hematológicas/diagnóstico por imagen , Enfermedades Hematológicas/patología , Humanos , Mutación con Pérdida de Función/genética , Masculino , Mutación/genética , Fenotipo , Enfermedades Vestibulares/diagnóstico por imagen , Enfermedades Vestibulares/patología , Secuenciación del Exoma , Adulto JovenRESUMEN
We investigated seven children from six families to expand the phenotypic spectrum associated with an early infantile epileptic encephalopathy caused by biallelic pathogenic variants in the phosphatidylinositol glycan anchor biosynthesis class Q (PIGQ) gene. The affected children were all identified by clinical or research exome sequencing. Clinical data, including EEGs and MRIs, was comprehensively reviewed and flow cytometry and transfection experiments were performed to investigate PIGQ function. Pathogenic biallelic PIGQ variants were associated with increased mortality. Epileptic seizures, axial hypotonia, developmental delay and multiple congenital anomalies were consistently observed. Seizure onset occurred between 2.5 months and 7 months of age and varied from treatable seizures to recurrent episodes of status epilepticus. Gastrointestinal issues were common and severe, two affected individuals had midgut volvulus requiring surgical correction. Cardiac anomalies including arrythmias were observed. Flow cytometry using granulocytes and fibroblasts from affected individuals showed reduced expression of glycosylphosphatidylinositol (GPI)-anchored proteins. Transfection of wildtype PIGQ cDNA into patient fibroblasts rescued this phenotype. We expand the phenotypic spectrum of PIGQ-related disease and provide the first functional evidence in human cells of defective GPI-anchoring due to pathogenic variants in PIGQ.
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Anomalías Múltiples/genética , Proteínas de la Membrana/genética , Hipotonía Muscular/genética , Convulsiones/genética , Espasmos Infantiles/genética , Anomalías Múltiples/diagnóstico , Anomalías Múltiples/metabolismo , Niño , Preescolar , Resultado Fatal , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Hipotonía Muscular/patología , Mutación Missense , Fenotipo , Convulsiones/diagnóstico , Convulsiones/metabolismo , Espasmos Infantiles/metabolismo , Espasmos Infantiles/patología , Secuenciación del ExomaRESUMEN
PURPOSE: Sixty to seventy-five percent of individuals with rare and undiagnosed phenotypes remain undiagnosed after exome sequencing (ES). With standard ES reanalysis resolving 10-15% of the ES negatives, further approaches are necessary to maximize diagnoses in these individuals. METHODS: In 38 ES negative patients an individualized genomic-phenotypic approach was employed utilizing (1) phenotyping; (2) reanalyses of FASTQ files, with innovative bioinformatics; (3) targeted molecular testing; (4) genome sequencing (GS); and (5) conferring of clinical diagnoses when pathognomonic clinical findings occurred. RESULTS: Certain and highly likely diagnoses were made in 18/38 (47%) individuals, including identifying two new developmental disorders. The majority of diagnoses (>70%) were due to our bioinformatics, phenotyping, and targeted testing identifying variants that were undetected or not prioritized on prior ES. GS diagnosed 3/18 individuals with structural variants not amenable to ES. Additionally, tentative diagnoses were made in 3 (8%), and in 5 individuals (13%) candidate genes were identified. Overall, diagnoses/potential leads were identified in 26/38 (68%). CONCLUSIONS: Our comprehensive approach to ES negatives maximizes the ES and clinical data for both diagnoses and candidate gene identification, without GS in the majority. This iterative approach is cost-effective and is pertinent to the current conundrum of ES negatives.
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Discapacidades del Desarrollo/diagnóstico , Discapacidades del Desarrollo/genética , Exoma/genética , Predisposición Genética a la Enfermedad , Niño , Discapacidades del Desarrollo/epidemiología , Femenino , Genómica , Humanos , Masculino , Fenotipo , Análisis de Secuencia de ADN , Secuenciación del Exoma/métodos , Secuenciación Completa del GenomaRESUMEN
PURPOSE: Haploinsufficiency of USP7, located at chromosome 16p13.2, has recently been reported in seven individuals with neurodevelopmental phenotypes, including developmental delay/intellectual disability (DD/ID), autism spectrum disorder (ASD), seizures, and hypogonadism. Further, USP7 was identified to critically incorporate into the MAGEL2-USP7-TRIM27 (MUST), such that pathogenic variants in USP7 lead to altered endosomal F-actin polymerization and dysregulated protein recycling. METHODS: We report 16 newly identified individuals with heterozygous USP7 variants, identified by genome or exome sequencing or by chromosome microarray analysis. Clinical features were evaluated by review of medical records. Additional clinical information was obtained on the seven previously reported individuals to fully elucidate the phenotypic expression associated with USP7 haploinsufficiency. RESULTS: The clinical manifestations of these 23 individuals suggest a syndrome characterized by DD/ID, hypotonia, eye anomalies,feeding difficulties, GERD, behavioral anomalies, and ASD, and more specific phenotypes of speech delays including a nonverbal phenotype and abnormal brain magnetic resonance image findings including white matter changes based on neuroradiologic examination. CONCLUSION: The consistency of clinical features among all individuals presented regardless of de novo USP7 variant type supports haploinsufficiency as a mechanism for pathogenesis and refines the clinical impact faced by affected individuals and caregivers.
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Discapacidad Intelectual/genética , Trastornos del Desarrollo del Lenguaje/genética , Trastornos del Neurodesarrollo/genética , Problema de Conducta , Adolescente , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/fisiopatología , Niño , Preescolar , Deleción Cromosómica , Proteínas de Unión al ADN/genética , Genoma Humano/genética , Haploinsuficiencia/genética , Humanos , Lactante , Recién Nacido , Discapacidad Intelectual/fisiopatología , Trastornos del Desarrollo del Lenguaje/fisiopatología , Trastornos del Neurodesarrollo/fisiopatología , Proteínas Nucleares/genética , Fenotipo , Proteínas/genética , Secuenciación del ExomaRESUMEN
While genomic sequencing (ES/GS) has the potential to diagnose children with difficult to diagnose phenotypes, the goal should be not only a diagnosis, but also to empower parents to seek next steps for their children and to emotionally manage the outcome, whether or not a diagnosis is secured. To help achieve this goal, objective measures are needed to assess the process of parental empowerment related to genome sequencing. We present the validity and reliability of the Genome Empowerment Scale (GEmS), developed using a healthcare empowerment theoretical model. To evaluate its psychometric properties, 158 parents of 117 children with an undiagnosed condition undergoing genomic sequencing completed the GEmS, measures for criterion validity and for depression and anxiety. Factor analysis resulted in a four factor solution: (a) meaning of a diagnosis; (b) emotional management of the process; (c) seeking information and support and (d) implications and planning. Reliability and validity analyses show that the GEmS has good psychometric properties. The inter-relationships among the factors revealed a profile that may identify parents at risk for a poorer outcome who may benefit from targeted genetic counseling. The GEmS, an objective measure of parental genomic empowerment, can be utilized for future research and translational applications.