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FRY-like transcription coactivator (FRYL) belongs to a Furry protein family that is evolutionarily conserved from yeast to humans. The functions of FRYL in mammals are largely unknown, and variants in FRYL have not previously been associated with a Mendelian disease. Here, we report fourteen individuals with heterozygous variants in FRYL who present with developmental delay, intellectual disability, dysmorphic features, and other congenital anomalies in multiple systems. The variants are confirmed de novo in all individuals except one. Human genetic data suggest that FRYL is intolerant to loss of function (LoF). We find that the fly FRYL ortholog, furry (fry), is expressed in multiple tissues, including the central nervous system where it is present in neurons but not in glia. Homozygous fry LoF mutation is lethal at various developmental stages, and loss of fry in mutant clones causes defects in wings and compound eyes. We next modeled four out of the five missense variants found in affected individuals using fry knockin alleles. One variant behaves as a severe LoF variant, whereas two others behave as partial LoF variants. One variant does not cause any observable defect in flies, and the corresponding human variant is not confirmed to be de novo, suggesting that this is a variant of uncertain significance. In summary, our findings support that fry is required for proper development in flies and that the LoF variants in FRYL cause a dominant disorder with developmental and neurological symptoms due to haploinsufficiency.
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Discapacidad Intelectual , Anomalías Musculoesqueléticas , Animales , Niño , Humanos , Discapacidades del Desarrollo/genética , Discapacidades del Desarrollo/diagnóstico , Discapacidad Intelectual/genética , Mamíferos , Anomalías Musculoesqueléticas/genética , Mutación Missense , Factores de Transcripción/genética , DrosophilaRESUMEN
PURPOSE: Genomic medicine can end diagnostic odysseys for patients with complex phenotypes; however, limitations in insurance coverage and other systemic barriers preclude individuals from accessing comprehensive genetics evaluation and testing. METHODS: The Texome Project is a 4-year study that reduces barriers to genomic testing for individuals from underserved and underrepresented populations. Participants with undiagnosed, rare diseases who have financial barriers to obtaining exome sequencing (ES) clinically are enrolled in the Texome Project. RESULTS: We highlight the Texome Project process and describe the outcomes of the first 60 ES results for study participants. Participants received a genetic evaluation, ES, and return of results at no cost. We summarize the psychosocial or medical implications of these genetic diagnoses. Thus far, ES provided molecular diagnoses for 18 out of 60 (30%) of Texome participants. Plus, in 11 out of 60 (18%) participants, a partial or probable diagnosis was identified. Overall, 5 participants had a change in medical management. CONCLUSION: To date, the Texome Project has recruited a racially, ethnically, and socioeconomically diverse cohort. The diagnostic rate and medical impact in this cohort support the need for expanded access to genetic testing and services. The Texome Project will continue reducing barriers to genomic care throughout the future study years.
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Secuenciación del Exoma , Pruebas Genéticas , Poblaciones Vulnerables , Humanos , Femenino , Masculino , Pruebas Genéticas/métodos , Adulto , Persona de Mediana Edad , Área sin Atención Médica , Exoma/genética , Accesibilidad a los Servicios de Salud , Adolescente , Genómica/métodos , Adulto Joven , AncianoRESUMEN
PURPOSE: TANGO2 deficiency disorder (TDD), an autosomal recessive disease first reported in 2016, is characterized by neurodevelopmental delay, seizures, intermittent ataxia, hypothyroidism, and life-threatening metabolic and cardiac crises. The purpose of this study was to define the natural history of TDD. METHODS: Data were collected from an ongoing natural history study of patients with TDD enrolled between February 2019 and May 2022. Data were obtained through phone or video based parent interviews and medical record review. RESULTS: Data were collected from 73 patients (59% male) from 57 unrelated families living in 16 different countries. The median age of participants at the time of data collection was 9.0 years (interquartile range = 5.3-15.9 years, range = fetal to 31.8 years). A total of 24 different TANGO2 alleles were observed. Patients showed normal development in early infancy, with progressive delay in developmental milestones thereafter. Symptoms included ataxia, dystonia, and speech difficulties, typically starting between the ages of 1 to 3 years. A total of 46/71 (65%) patients suffered metabolic crises, and of those, 30 (65%) developed cardiac crises. Metabolic crises were significantly decreased after the initiation of B-complex or multivitamin supplementation. CONCLUSION: We provide the most comprehensive review of natural history of TDD and important observational data suggesting that B-complex or multivitamins may prevent metabolic crises.
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Ataxia , Convulsiones , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Embarazo , Atención PrenatalRESUMEN
Medications that elicit an alternate pathway for nitrogen excretion such as oral sodium phenylbutyrate (NaPBA) and glycerol phenylbutyrate (GPB) and intravenous sodium phenylacetate (NaPAA) are important for the management of urea cycle disorders (UCDs). Plasma concentrations of their primary metabolite, phenylacetate (PAA), as well as the ratio of PAA to phenylacetylglutamine (PAGN) are useful for guiding dosing and detecting toxicity. However, the frequency of toxic elevations of metabolites and associated clinical covariates is relatively unknown. A retrospective analysis was conducted on 1255 plasma phenylbutyrate metabolite measurements from 387 individuals. An additional analysis was also conducted on a subset of 68 individuals in whom detailed clinical information was available. In the course of these analyses, abnormally elevated plasma PAA and PAA:PAGN were identified in 39 individuals (4.15% of samples) and 42 individuals (4.30% of samples), respectively. Abnormally elevated PAA and PAA:PAGN values were more likely to occur in younger individuals and associate positively with dose of NAPBA and negatively with plasma glutamine and glycine levels. These results demonstrate that during routine clinical management, the majority of patients have PAA levels that are deemed safe. As age is negatively associated with PAA levels however, children undergoing treatment with NaPBA may need close monitoring of their phenylbutyrate metabolite levels.
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Fenilbutiratos , Trastornos Innatos del Ciclo de la Urea , Niño , Humanos , Estudios RetrospectivosRESUMEN
PURPOSE: In 2011, we introduced an innovative parallel curriculum at Baylor College of Medicine, formerly called the Genetics Track Curriculum and now called the Genetics and Genomics Pathway, aimed at providing an opportunity for an enriched educational experience throughout medical school. In this report, we describe our 10-year experience with the program and highlight growth in enrollment as well as academic achievements of graduating students. METHODS: We reviewed the data of students enrolled in this pathway, including retention, satisfaction, student-driven curriculum changes, scholarly outcomes, and career outcomes. RESULTS: From September 2011 to June 2021, 121 students were enrolled in the Genetics and Genomics Pathway program. In total, 64 students (64/121 = 53%) left the program before graduating (the majority, after their first year). Of the 57 remaining students, 29 graduated (29/57, approximately 51%), and 4 of the 29 students (4/29 = 14%) matched into a genetics training program. CONCLUSION: This novel program serves as a mechanism for garnering increased interest and competence in medical genetics. The longitudinal nature of the program fosters enthusiasm for genetics and provides ample opportunity to develop valuable research skills. Given the ongoing shortage of providers in this field, such programs are vital to increase the size of the workforce and broaden the knowledge of providers in diverse fields.
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Educación de Pregrado en Medicina , Estudiantes de Medicina , Curriculum , Genómica , Humanos , Facultades de Medicina , Recursos HumanosRESUMEN
PURPOSE OF REVIEW: To present new therapeutic modalities for inborn errors of metabolism that are in clinical trials or recently approved by the US Food and Drug Administration (FDA) and to improve pediatricians' understanding of therapies their patients with inborn errors of metabolism receive. RECENT FINDINGS: New therapies that move beyond the old standard modalities of recombinant human enzyme therapies, diet and medications have been recently approved by the US FDA to include nonhuman enzyme therapies, gene therapy and chaperone therapies. SUMMARY: These new therapies offer more therapeutic options for individuals with inborn errors of metabolism. These new therapies have the potential to improve patient compliance and outcomes. Many other novel modalities are in the development pipeline, and are likely to transform the management of inborn errors of metabolism over the coming decade.
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Errores Innatos del Metabolismo , Humanos , Errores Innatos del Metabolismo/genética , Dieta , Terapia GenéticaRESUMEN
Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL), defined primarily by developmental delay/intellectual disability, speech delay, postnatal microcephaly, and dysmorphic features, is a syndrome resulting from heterozygous variants in the dosage-sensitive bromodomain PHD finger chromatin remodeler transcription factor BPTF gene. To date, only 11 individuals with NEDDFL due to de novo BPTF variants have been described. To expand the NEDDFL phenotypic spectrum, we describe the clinical features in 25 novel individuals with 20 distinct, clinically relevant variants in BPTF, including four individuals with inherited changes in BPTF. In addition to the previously described features, individuals in this cohort exhibited mild brain abnormalities, seizures, scoliosis, and a variety of ophthalmologic complications. These results further support the broad and multi-faceted complications due to haploinsufficiency of BPTF.
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Ensamble y Desensamble de Cromatina/genética , Epilepsia/genética , Microcefalia/genética , Trastornos del Neurodesarrollo/genética , Anomalías Múltiples/genética , Anomalías Múltiples/fisiopatología , Adolescente , Adulto , Niño , Preescolar , Deleción Cromosómica , Discapacidades del Desarrollo/genética , Discapacidades del Desarrollo/fisiopatología , Epilepsia/fisiopatología , Facies , Femenino , Haploinsuficiencia/genética , Humanos , Lactante , Discapacidad Intelectual/genética , Discapacidad Intelectual/fisiopatología , Trastornos del Desarrollo del Lenguaje/genética , Trastornos del Desarrollo del Lenguaje/fisiopatología , Masculino , Microcefalia/fisiopatología , Persona de Mediana Edad , Trastornos del Neurodesarrollo/fisiopatología , Fenotipo , Factores de Transcripción/genética , Adulto JovenRESUMEN
PURPOSE: A primary barrier to improving exome sequencing diagnostic rates is the interpretation of variants of uncertain clinical significance. We aimed to determine the contribution of integrated untargeted metabolomics in the analysis of exome sequencing data by retrospective analysis of patients evaluated by both exome sequencing and untargeted metabolomics within the same clinical laboratory. METHODS: Exome sequencing and untargeted metabolomic data were collected and analyzed for 170 patients. Pathogenic variants, likely pathogenic variants, and variants of uncertain significance in genes associated with a biochemical phenotype were extracted. Metabolomic data were evaluated to determine if these variants resulted in biochemical abnormalities that could be used to support their interpretation using current American College of Genetics and Genomics (ACMG) guidelines. RESULTS: Metabolomic data contributed to the interpretation of variants in 74 individuals (43.5%) over 73 different genes. The data allowed for the reclassification of 9 variants as likely benign, 15 variants as likely pathogenic, and 3 variants as pathogenic. Metabolomic data confirmed a clinical diagnosis in 21 cases, for a diagnostic rate of 12.3% in this population. CONCLUSION: Untargeted metabolomics can serve as a useful adjunct to exome sequencing by providing valuable functional data that may not otherwise be clinically available, resulting in improved variant classification.
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Exoma , Variación Genética , Exoma/genética , Humanos , Metabolómica , Estudios Retrospectivos , Secuenciación del ExomaRESUMEN
Pulmonary hypertension (pHTN) is a severe, life-threatening disease, which can be idiopathic or associated with an underlying syndrome or genetic diagnosis. Here we discuss a patient who presented with severe pHTN and was later found to be compound heterozygous for pathogenic variants in the NFU1 gene causing multiple mitochondrial dysfunctions syndrome 1 (MMDS1). Review of autopsy slides from an older sibling revealed the same diagnosis along with pulmonary findings consistent with a developmental lung disorder. In particular, these postmortem, autopsy findings have not been described previously in humans with this mitochondrial syndrome and suggest a possible developmental basis for the severe pHTN seen in this disease. Given the rarity of patients reported with MMDS1, we review the current state of knowledge of this disease and our novel management strategies for pHTN and MMDS1-associated complications in this population.
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Proteínas Portadoras/genética , Discapacidades del Desarrollo/etiología , Hipertensión Pulmonar/etiología , Enfermedades Mitocondriales/complicaciones , Mutación , Discapacidades del Desarrollo/patología , Femenino , Humanos , Hipertensión Pulmonar/patología , Recién Nacido , Masculino , Enfermedades Mitocondriales/genética , PronósticoRESUMEN
Sudden Infant Death with Dysgenesis of the Testes syndrome (SIDDT) is a very rare condition associated with biallelic pathogenic variants in the TSPYL1 gene first reported in 2004. It is characterized by sudden cardiac or respiratory arrest, disordered testicular development, neurologic dysfunction, and is uniformly fatal before the age of 12 months. There were previously 21 reported cases of SIDDT in the literature, all from nine Old Order Amish families published in a single paper. In this report, we describe a non-Amish, phenotypically female infant with poor feeding and abnormal motor movements noted at birth. Initial testing showed that she had a 46,XY chromosome complement, and chromosomal microarray showed a significant absence of heterozygosity (AOH) totalling roughly 600 Mb across multiple different chromosomes, indicating consanguinity. Further workup with exome sequencing revealed homozygosity for a frameshift variant in TSPYL1 (c.725_726delTG, p.Val242GlufsTer52) consistent with a diagnosis of SIDDT, explaining many of her clinical features. However, she was also noted to have a mild T-cell lymphopenia and developed intractable epilepsy after hospital discharge. These features have not previously been reported in SIDDT and may represent phenotypic expansion. To our knowledge, this patient is the 22nd case of SIDDT to be reported in the literature, and the first to be of non-Amish heritage.
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Mutación , Proteínas Nucleares/genética , Fenotipo , Muerte Súbita del Lactante/patología , Testículo/anomalías , Amish , Femenino , Humanos , Recién Nacido , Muerte Súbita del Lactante/genética , Testículo/patología , Secuenciación del ExomaRESUMEN
The myelin regulatory factor gene (MYRF) encodes a transcription factor that is widely expressed. There is increasing evidence that heterozygous loss-of-function variants in MYRF can lead to abnormal development of the heart, genitourinary tract, diaphragm, and lungs. Here, we searched a clinical database containing the results of 12,000 exome sequencing studies. We identified three previously unreported males with putatively deleterious variants in MYRF: one with a point mutation predicted to affect splicing and two with frameshift variants. In all cases where parental DNA was available, these variants were found to have arisen de novo. The phenotypes identified in these subjects included a variety of congenital heart defects (CHD) (hypoplastic left heart syndrome, scimitar syndrome, septal defects, and valvular anomalies), genitourinary anomalies (ambiguous genitalia, hypospadias, and cryptorchidism), congenital diaphragmatic hernia, and pulmonary hypoplasia. The phenotypes seen in our subjects overlap those described in individuals diagnosed with PAGOD syndrome [MIM# 202660], a clinically defined syndrome characterized by pulmonary artery and lung hypoplasia, agonadism, omphalocele, and diaphragmatic defects that can also be associated with hypoplastic left heart and scimitar syndrome. These cases provide additional evidence that haploinsufficiency of MYRF causes a genetic syndrome whose cardinal features include CHD, urogenital anomalies, congenital diaphragmatic hernia, and pulmonary hypoplasia. We also conclude that consideration should be given to screening individuals with PAGOD for pathogenic variants in MYRF, and that individuals with MYRF deficiency who survive the neonatal period should be monitored closely for developmental delay and intellectual disability.
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Haploinsuficiencia , Proteínas de la Membrana/genética , Fenotipo , Factores de Transcripción/genética , Secuencia de Aminoácidos , Femenino , Humanos , Recién Nacido , Masculino , Proteínas de la Membrana/química , Homología de Secuencia de Aminoácido , Factores de Transcripción/químicaRESUMEN
Serine biosynthesis defects are autosomal recessive metabolic disorders resulting from the deficiency of any of the three enzymes involved in de novo serine biosynthesis, specifically phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). In this study, we performed metabolomic profiling on 4 children with serine biosynthesis defects; 3 with PGDH deficiency and 1 with PSAT deficiency. The evaluations were performed at baseline and with serine and glycine supplementation. Metabolomic profiling performed at baseline showed low phospholipid species, including glycerophosphocholine, glycerophosphoethanolamine, and sphingomyelin. All children had low serine and glycine as expected. Low glycerophosphocholine compounds were found in 4 children, low glycerophosphoethanolamine compounds in 3 children, and low sphingomyelin species in 2 children. Metabolic profiling with serine and glycine supplementation showed normalization of most of the low phospholipid compounds in the 4 children. Phospholipids are the major component of plasma and intracellular membranes, and phosphatidylcholine is the most abundant phospholipid of all mammalian cell types and subcellular organelles. Phosphatidylcholine is of particular importance for the nervous system, where it is essential for neuronal differentiation. The observed low phosphatidylcholine species in children with serine biosynthesis defects that improved after serine supplementation, supports the role of serine as a significant precursor for phosphatidylcholine. The vital role that phosphatidylcholine has during neuronal differentiation and the pronounced neurological manifestations in serine biosynthesis defects suggest that phosphatidylcholine deficiency occurring secondary to serine deficiency may have a significant contribution to the development of the neurological manifestations in individuals with serine biosynthesis defects.
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Errores Innatos del Metabolismo de los Carbohidratos/metabolismo , Suplementos Dietéticos , Glicina/administración & dosificación , Microcefalia/metabolismo , Fosfatidilcolinas/metabolismo , Fosfoglicerato-Deshidrogenasa/deficiencia , Trastornos Psicomotores/metabolismo , Convulsiones/metabolismo , Serina/biosíntesis , Transaminasas/deficiencia , Errores Innatos del Metabolismo de los Carbohidratos/sangre , Errores Innatos del Metabolismo de los Carbohidratos/dietoterapia , Diferenciación Celular , Niño , Preescolar , Femenino , Glicina/sangre , Humanos , Lactante , Masculino , Metabolómica/métodos , Microcefalia/sangre , Microcefalia/dietoterapia , Neuronas/metabolismo , Fosfoglicerato-Deshidrogenasa/sangre , Fosfoglicerato-Deshidrogenasa/metabolismo , Trastornos Psicomotores/sangre , Trastornos Psicomotores/dietoterapia , Convulsiones/sangre , Convulsiones/dietoterapia , Serina/administración & dosificación , Serina/sangre , Transaminasas/sangre , Transaminasas/metabolismoRESUMEN
A 7-week-old infant presented to the emergency department with fussiness, decreased oral intake, loose stool, and respiratory distress for 2 days. The patient was born full-term with an uncomplicated birth history but had a history of slow weight gain. He was alert, but toxic-appearing at presentation, hypothermic with signs of dehydration, and with respiratory failure. He was found to have severe anion gap metabolic acidosis, hypokalemia, elevated lactate, and hyperammonemia. He responded well to initial resuscitation and was admitted to the ICU for intravenous electrolyte replacement, bowel rest, and respiratory support. A workup was pursued for failure to thrive with severe malnutrition, hyperammonemia, hyperlactatemia, anemia, vitamin D deficiency, and electrolyte abnormalities. After stabilization, he was restarted on enteral feeds and had a recurrence of loose stool and severe electrolyte abnormalities, which were refractory to enteral supplementations and required readmission to the ICU. His hospital course extended several weeks, included several subspecialty consultations, and ended with a surprising diagnosis of exclusion based on his clinical response to therapy.
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Genomic sequencing offers an untargeted, data-driven approach to genetic diagnosis; however, variants of uncertain significance often hinder the diagnostic process. The discovery of rare genomic variants without previously known functional evidence of pathogenicity often results in variants being overlooked as potentially causative, particularly in individuals with undifferentiated phenotypes. Consequently, many neurometabolic conditions, including those in the GABA (gamma-aminobutyric acid) catabolism pathway, are underdiagnosed. Succinic semialdehyde dehydrogenase deficiency (SSADHD, OMIM #271980) is a neurometabolic disorder in the GABA catabolism pathway. The disorder is due to bi-allelic pathogenic variants in ALDH5A1 and is usually characterized by moderate-to-severe developmental delays, hypotonia, intellectual disability, ataxia, seizures, hyperkinetic behavior, aggression, psychiatric disorders, and sleep disturbances. In this study, we utilized an integrated approach to diagnosis of SSADHD by examining molecular, clinical, and metabolomic data from a single large commercial laboratory. Our analysis led to the identification of 16 patients with likely SSADHD along with three novel variants. We also showed that patients with this disorder have a clear metabolomic signature that, along with molecular and clinical findings, may allow for more rapid and efficient diagnosis. We further surveyed all available pathogenic/likely pathogenic variants and used this information to estimate the global prevalence of this disease. Taken together, our comprehensive analysis allows for a global approach to the diagnosis of SSADHD and provides a pathway to improved diagnosis and potential incorporation into newborn screening programs. Furthermore, early diagnosis facilitates referral to genetic counseling, family support, and access to targeted treatments-taken together, these provide the best outcomes for individuals living with either GABA-TD or SSADHD, as well as other rare conditions.
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BACKGROUND: Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL) is associated to BPTF gene haploinsufficiency. Epilepsy was not included in the initial descriptions of NEDDFL, but emerging evidence indicates that epileptic seizures occur in some affected individuals. This study aims to investigate the electroclinical epilepsy features in individuals with NEDDFL. METHODS: We enrolled individuals with BPTF-related seizures or interictal epileptiform discharges (IEDs) on electroencephalography (EEG). Demographic, clinical, genetic, raw EEG, and neuroimaging data as well as response to antiseizure medication were assessed. RESULTS: We studied 11 individuals with a null variant in BPTF, including five previously unpublished ones. Median age at last observation was 9 years (range: 4 to 43 years). Eight individuals had epilepsy, one had a single unprovoked seizure, and two showed IEDs only. Key features included (1) early childhood epilepsy onset (median 4 years, range: 10 months to 7 years), (2) well-organized EEG background (all cases) and brief bursts of spikes and slow waves (50% of individuals), and (3) developmental delay preceding seizure onset. Spectrum of epilepsy severity varied from drug-resistant epilepsy (27%) to isolated IEDs without seizures (18%). Levetiracetam was widely used and reduced seizure frequency in 67% of the cases. CONCLUSIONS: Our study provides the first characterization of BPTF-related epilepsy. Early-childhood-onset epilepsy occurs in 19% of subjects, all presenting with a well-organized EEG background associated with generalized interictal epileptiform abnormalities in half of these cases. Drug resistance is rare.
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Electroencefalografía , Epilepsia , Fenotipo , Humanos , Niño , Masculino , Femenino , Preescolar , Epilepsia/fisiopatología , Epilepsia/tratamiento farmacológico , Epilepsia/genética , Adolescente , Adulto , Adulto JovenRESUMEN
Precision medicine for Mendelian epilepsy is rapidly developing. We describe an early infant with severely pharmacoresistant multifocal epilepsy. Exome sequencing revealed the de novo variant p.(Leu296Phe) in the gene KCNA1, encoding the voltage-gated K+ channel subunit KV 1.1. So far, loss-of-function variants in KCNA1 have been associated with episodic ataxia type 1 or epilepsy. Functional studies of the mutated subunit in oocytes revealed a gain-of-function caused by a hyperpolarizing shift of voltage dependence. Leu296Phe channels are sensitive to block by 4-aminopyridine. Clinical use of 4-aminopyridine was associated with reduced seizure burden, enabled simplification of co-medication and prevented rehospitalization.
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Epilepsia Generalizada , Epilepsia , Humanos , 4-Aminopiridina/farmacología , 4-Aminopiridina/uso terapéutico , Mutación con Ganancia de Función , Mutación , Epilepsia/tratamiento farmacológico , Epilepsia/genética , Canal de Potasio Kv.1.1/genéticaRESUMEN
Though biallelic variants in SLC13A5 are known to cause severe encephalopathy, the mechanism of this disease is poorly understood. SLC13A5 protein deficiency reduces citrate transport into the cell. Downstream abnormalities in fatty acid synthesis and energy generation have been described, though biochemical signs of these perturbations are inconsistent across SLC13A5 deficiency patients. To investigate SLC13A5-related disorders, we performed untargeted metabolic analyses on the liver, brain, and serum from a Slc13a5-deficient mouse model. Metabolomic data were analyzed using the connect-the-dots (CTD) methodology and were compared to plasma and CSF metabolomics from SLC13A5-deficient patients. Mice homozygous for the Slc13a5tm1b/tm1b null allele had perturbations in fatty acids, bile acids, and energy metabolites in all tissues examined. Further analyses demonstrated that for several of these molecules, the ratio of their relative tissue concentrations differed widely in the knockout mouse, suggesting that deficiency of Slc13a5 impacts the biosynthesis and flux of metabolites between tissues. Similar findings were observed in patient biofluids, indicating altered transport and/or flux of molecules involved in energy, fatty acid, nucleotide, and bile acid metabolism. Deficiency of SLC13A5 likely causes a broader state of metabolic dysregulation than previously recognized, particularly regarding lipid synthesis, storage, and metabolism, supporting SLC13A5 deficiency as a lipid disorder.
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BACKGROUND: TANGO2 deficiency disorder (TDD) is an autosomal recessive disease associated with metabolic crisis, lethal cardiac arrhythmias, and cardiomyopathy. Data regarding treatment, management, and outcomes of cardiac manifestations of TDD are lacking. OBJECTIVE: The purpose of this study was to describe TDD-related cardiac crises. METHODS: Retrospective multicenter chart review was made of TDD patients admitted with cardiac crises, defined as development of ventricular tachycardia (VT), cardiomyopathy, or cardiac arrest during metabolic crises. RESULTS: Twenty-seven children were admitted for 43 cardiac crises (median age 6.4 years; interquartile range [IQR] 2.4-9.8 years) at 14 centers. During crisis, QTc prolongation occurred in all (median 547 ms; IQR 504-600 ms) and a type I Brugada pattern in 8 (26%). Arrhythmias included VT in 21 (78%), supraventricular tachycardia in 3 (11%), and heart block in 1 (4%). Nineteen patients (70%) developed cardiomyopathy, and 20 (74%) experienced a cardiac arrest. There were 10 deaths (37%), 6 related to arrhythmias. In 5 patients, recalcitrant VT occurred despite use of antiarrhythmic drugs. In 6 patients, arrhythmias were controlled after extracorporeal membrane oxygenation (ECMO) support; 5 of these patients survived. Among 10 patients who survived VT without ECMO, successful treatment included intravenous magnesium, isoproterenol, and atrial pacing in multiple cases and verapamil in 1 patient. Initiation of feeds seemed to decrease VT events. CONCLUSION: TDD-related cardiac crises are associated with a high risk of arrhythmias, cardiomyopathy, cardiac arrest, and death. Although further studies are needed, early recognition and appropriate treatment are critical. Acutely, intravenous magnesium, isoproterenol, atrial pacing, and ECMO as a last resort seem to be the best current treatment options, and early initiation of feeds may prevent VT events.
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Cardiomiopatías , Paro Cardíaco , Taquicardia Ventricular , Antiarrítmicos/uso terapéutico , Arritmias Cardíacas/etiología , Arritmias Cardíacas/terapia , Cardiomiopatías/complicaciones , Cardiomiopatías/diagnóstico , Niño , Paro Cardíaco/etiología , Paro Cardíaco/terapia , Humanos , Isoproterenol , Magnesio , VerapamiloRESUMEN
Background: As genetic testing increasingly integrates into the practice of nephrology, our understanding of the basis of many kidney disorders has exponentially increased. Given this, we recently initiated a Renal Genetics Clinic (RGC) at our large, urban children's hospital for patients with kidney disorders. Methods: Genetic testing was performed in Clinical Laboratory Improvement Amendments-certified laboratories using single gene testing, multigene panels, chromosomal microarray, or exome sequencing. Results: A total of 192 patients were evaluated in this clinic, with cystic kidney disease (49/192) being the most common reason for referral, followed by congenital anomalies of the kidney and urinary tract (41/192) and hematuria (38/192). Genetic testing was performed for 158 patients, with an overall diagnostic yield of 81 out of 158 (51%). In the 16 out of 81 (20%) of patients who reached a genetic diagnosis, medical or surgical treatment of the patients were affected, and previous clinical diagnoses were changed to more accurate genetic diagnoses in 12 of 81 (15%) patients. Conclusions: Our genetic testing provided an accurate diagnosis for children and, in some cases, led to further diagnoses in seemingly asymptomatic family members and changes to overall medical management. Genetic testing, as facilitated by such a specialized clinical setting, thus appears to have clear utility in the diagnosis and counseling of patients with a wide range of kidney manifestations.
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Enfermedades Renales , Sistema Urinario , Niño , Pruebas Genéticas , Humanos , Riñón/anomalías , Enfermedades Renales/diagnóstico , Sistema Urinario/anomalías , Secuenciación del ExomaRESUMEN
Importance: Recent advances in newborn screening (NBS) have improved the diagnosis of inborn errors of metabolism (IEMs); however, many potentially treatable IEMs are not included on NBS panels, nor are they covered in standard, first-line biochemical testing. Objective: To examine the utility of untargeted metabolomics as a primary screening tool for IEMs by comparing the diagnostic rate of clinical metabolomics with the recommended traditional metabolic screening approach. Design, Setting, and Participants: This cross-sectional study compares data from 4464 clinical samples received from 1483 unrelated families referred for trio testing of plasma amino acids, plasma acylcarnitine profiling, and urine organic acids (June 2014 to October 2018) and 2000 consecutive plasma samples from 1807 unrelated families (July 2014 to February 2019) received for clinical metabolomic screening at a College of American Pathologists and Clinical Laboratory Improvement Amendments-certified biochemical genetics laboratory. Data analysis was performed from September 2019 to August 2020. Exposures: Metabolic and molecular tests performed at a genetic testing reference laboratory in the US and available clinical information for each patient were assessed to determine diagnostic rate. Main Outcomes and Measures: The diagnostic rate of traditional metabolic screening compared with clinical metabolomic profiling was assessed in the context of expanded NBS. Results: Of 1483 cases screened by the traditional approach, 912 patients (61.5%) were male and 1465 (98.8%) were pediatric (mean [SD] age, 4.1 [6.0] years; range, 0-65 years). A total of 19 families were identified with IEMs, resulting in a 1.3% diagnostic rate. A total of 14 IEMs were detected, including 3 conditions not included in the Recommended Uniform Screening Panel for NBS. Of the 1807 unrelated families undergoing plasma metabolomic profiling, 1059 patients (58.6%) were male, and 1665 (92.1%) were pediatric (mean [SD] age, 8.1 [10.4] years; range, 0-80 years). Screening identified 128 unique cases with IEMs, giving an overall diagnostic rate of 7.1%. In total, 70 different metabolic conditions were identified, including 49 conditions not presently included on the Recommended Uniform Screening Panel for NBS. Conclusions and Relevance: These findings suggest that untargeted metabolomics provided a 6-fold higher diagnostic yield compared with the conventional screening approach and identified a broader spectrum of IEMs. Notably, with the expansion of NBS programs, traditional metabolic testing approaches identify few disorders beyond those covered on the NBS. These data support the capability of clinical untargeted metabolomics in screening for IEMs and suggest that broader screening approaches should be considered in the initial evaluation for metabolic disorders.