RESUMEN
INTRODUCTION: Patients with ADTKD-MUC1 have one allele producing normal mucin-1 (MUC1) and one allele producing mutant MUC1, which remains intracellular. We hypothesized that ADTKD-MUC1 patients, who have only 1 secretory-competent wild-type MUC1 allele, should exhibit decreased plasma mucin-1 (MUC1) levels. To test this hypothesis, we repurposed the serum CA15-3 assay used to measure MUC1 in breast cancer to measure plasma MUC1 levels in ADTKD-MUC1. METHODS: This cross-sectional study analyzed CA15-3 levels in a reference population of 6,850 individuals, in 85 individuals with ADTKD-MUC1, and in a control population including 135 individuals with ADTKD-UMOD and 114 healthy individuals. RESULTS: Plasma CA15-3 levels (mean ± standard deviation) were 8.6 ± 4.3 U/mL in individuals with ADTKD-MUC1 and 14.6 ± 5.6 U/mL in controls (p < 0.001). While there was a significant difference in mean CA15-3 levels, there was substantial overlap between the 2 groups. Plasma CA15-3 levels were <5 U/mL in 22% of ADTKD-MUC1 patients, in 0/249 controls, and in 1% of the reference population. Plasma CA15-3 levels were >20 U/mL in 1/85 ADTKD-MUC1 patients, in 18% of control individuals, and in 25% of the reference population. Segregation of plasma CA15-3 levels by the rs4072037 genotype did not significantly improve differentiation between affected and unaffected individuals. CA15-3 levels were minimally affected by gender and estimated glomerular filtration rate. DISCUSSION/CONCLUSIONS: Plasma CA15-3 levels in ADTKD-MUC1 patients are approximately 40% lower than levels in healthy individuals, though there is significant overlap between groups. Further investigations need to be performed to see if plasma CA15-3 levels would be useful in diagnosis, prognosis, or assessing response to new therapies in this disorder.
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Mucina-1/sangre , Nefritis Intersticial/sangre , Uromodulina/genética , Adulto , Anciano , Alelos , Biomarcadores/sangre , Estudios de Casos y Controles , Estudios Transversales , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Mucina-1/genética , Mutación , Nefritis Intersticial/genética , PronósticoRESUMEN
Autosomal-dominant tubulo-interstitial kidney disease (ADTKD) encompasses a group of disorders characterized by renal tubular and interstitial abnormalities, leading to slow progressive loss of kidney function requiring dialysis and kidney transplantation. Mutations in UMOD, MUC1, and REN are responsible for many, but not all, cases of ADTKD. We report on two families with ADTKD and congenital anemia accompanied by either intrauterine growth retardation or neutropenia. Ultrasound and kidney biopsy revealed small dysplastic kidneys with cysts and tubular atrophy with secondary glomerular sclerosis, respectively. Exclusion of known ADTKD genes coupled with linkage analysis, whole-exome sequencing, and targeted re-sequencing identified heterozygous missense variants in SEC61A1-c.553A>G (p.Thr185Ala) and c.200T>G (p.Val67Gly)-both affecting functionally important and conserved residues in SEC61. Both transiently expressed SEC6A1A variants are delocalized to the Golgi, a finding confirmed in a renal biopsy from an affected individual. Suppression or CRISPR-mediated deletions of sec61al2 in zebrafish embryos induced convolution defects of the pronephric tubules but not the pronephric ducts, consistent with the tubular atrophy observed in the affected individuals. Human mRNA encoding either of the two pathogenic alleles failed to rescue this phenotype as opposed to a complete rescue by human wild-type mRNA. Taken together, these findings provide a mechanism by which mutations in SEC61A1 lead to an autosomal-dominant syndromic form of progressive chronic kidney disease. We highlight protein translocation defects across the endoplasmic reticulum membrane, the principal role of the SEC61 complex, as a contributory pathogenic mechanism for ADTKD.
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Anemia/genética , Heterocigoto , Enfermedades Renales/genética , Mutación , Canales de Translocación SEC/genética , Adulto , Anciano , Alelos , Secuencia de Aminoácidos , Animales , Biopsia , Niño , Enfermedad Crónica , Progresión de la Enfermedad , Retículo Endoplásmico/metabolismo , Exoma/genética , Femenino , Retardo del Crecimiento Fetal/genética , Genes Dominantes , Aparato de Golgi/metabolismo , Humanos , Recién Nacido , Enfermedades Renales/patología , Masculino , Persona de Mediana Edad , Modelos Moleculares , Mutación Missense/genética , Neutropenia/genética , Linaje , Fenotipo , ARN Mensajero/análisis , ARN Mensajero/genética , Canales de Translocación SEC/química , Síndrome , Adulto Joven , Pez Cebra/embriología , Pez Cebra/genéticaRESUMEN
BACKGROUND: Autosomal dominant tubulointerstitial kidney disease caused by mucin-1 gene (MUC1) mutations (ADTKD-MUC1) is characterized by progressive kidney failure. Genetic evaluation for ADTKD-MUC1 specifically tests for a cytosine duplication that creates a unique frameshift protein (MUC1fs). Our goal was to develop immunohistochemical methods to detect the MUC1fs created by the cytosine duplication and, possibly, by other similar frameshift mutations and to identify novel MUC1 mutations in individuals with positive immunohistochemical staining for the MUC1fs protein. METHODS: We performed MUC1fs immunostaining on urinary cell smears and various tissues from ADTKD-MUC1-positive and -negative controls as well as in individuals from 37 ADTKD families that were negative for mutations in known ADTKD genes. We used novel analytic methods to identify MUC1 frameshift mutations. RESULTS: After technique refinement, the sensitivity and specificity for MUC1fs immunostaining of urinary cell smears were 94.2% and 88.6%, respectively. Further genetic testing on 17 families with positive MUC1fs immunostaining revealed six families with five novel MUC1 frameshift mutations that all predict production of the identical MUC1fs protein. CONCLUSIONS: We developed a noninvasive immunohistochemical method to detect MUC1fs that, after further validation, may be useful in the future for diagnostic testing. Production of the MUC1fs protein may be central to the pathogenesis of ADTKD-MUC1.
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Predisposición Genética a la Enfermedad/epidemiología , Mucina-1/genética , Riñón Poliquístico Autosómico Dominante/genética , Riñón Poliquístico Autosómico Dominante/patología , Biopsia con Aguja , Estudios de Casos y Controles , Femenino , Humanos , Inmunohistoquímica , Incidencia , Masculino , Mutación/genética , Linaje , Riñón Poliquístico Autosómico Dominante/mortalidad , Pronóstico , Sistema de Registros , Estudios Retrospectivos , Medición de RiesgoRESUMEN
The Acadian variant of Fanconi Syndrome refers to a specific condition characterized by generalized proximal tubular dysfunction from birth, slowly progressive chronic kidney disease and pulmonary interstitial fibrosis. This condition occurs only in Acadians, a founder population in Nova Scotia, Canada. The genetic and molecular basis of this disease is unknown. We carried out whole exome and genome sequencing and found that nine affected individuals were homozygous for the ultra-rare non-coding variant chr8:96046914 T > C; rs575462405, whereas 13 healthy siblings were either heterozygotes or lacked the mutant allele. This variant is located in intron 2 of NDUFAF6 (NM_152416.3; c.298-768 T > C), 37 base pairs upstream from an alternative splicing variant in NDUFAF6 chr8:96046951 A > G; rs74395342 (c.298-731 A > G). NDUFAF6 encodes NADH:ubiquinone oxidoreductase complex assembly factor 6, also known as C8ORF38. We found that rs575462405-either alone or in combination with rs74395342-affects splicing and synthesis of NDUFAF6 isoforms. Affected kidney and lung showed specific loss of the mitochondria-located NDUFAF6 isoform and ultrastructural characteristics of mitochondrial dysfunction. Accordingly, affected tissues had defects in mitochondrial respiration and complex I biogenesis that were corrected with NDUFAF6 cDNA transfection. Our results demonstrate that the Acadian variant of Fanconi Syndrome results from mitochondrial respiratory chain complex I deficiency. This information may be used in the diagnosis and prevention of this disease in individuals and families of Acadian descent and broadens the spectrum of the clinical presentation of mitochondrial diseases, respiratory chain defects and defects of complex I specifically.
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Complejo I de Transporte de Electrón/genética , Síndrome de Fanconi/genética , Mitocondrias/metabolismo , Enfermedades Mitocondriales/genética , Proteínas Mitocondriales/genética , Adulto , Alelos , Canadá , Mapeo Cromosómico , Exoma/genética , Síndrome de Fanconi/patología , Femenino , Predisposición Genética a la Enfermedad , Heterocigoto , Homocigoto , Humanos , Riñón/metabolismo , Riñón/patología , Pulmón/metabolismo , Pulmón/patología , Masculino , Persona de Mediana Edad , Mitocondrias/patología , Enfermedades Mitocondriales/metabolismo , Enfermedades Mitocondriales/patología , MutaciónRESUMEN
Cardiomyopathy is a common manifestation in neonates and infants with mitochondrial disorders. In this study, we report two cases manifesting with fatal mitochondrial hypertrophic cardiomyopathy, which include the third known patient with thymidine kinase 2 deficiency and the ninth patient with alanyl-tRNA synthetase 2 deficiency. The girl with thymidine kinase 2 deficiency had hypertrophic cardiomyopathy together with regression of gross motor development at the age of 13 months. Neurological symptoms and cardiac involvement progressed into severe myopathy, psychomotor arrest, and cardiorespiratory failure at the age of 22 months. The imaging methods and autoptic studies proved that she suffered from unique findings of leucoencephalopathy, severe, mainly cerebellar neuronal degeneration, and hepatic steatosis. The girl with alanyl-tRNA synthetase 2 deficiency presented with cardiac failure and underlying hypertrophic cardiomyopathy within 12 hours of life and subsequently died at 9 weeks of age. Muscle biopsy analyses demonstrated respiratory chain complex I and IV deficiencies, and histological evaluation revealed massive mitochondrial accumulation and cytochrome c oxidase-negative fibres in both cases. Exome sequencing in the first case revealed compound heterozygozity for one novel c.209T>C and one previously published c.416C>T mutation in the TK2 gene, whereas in the second case homozygozity for the previously described mutation c.1774C>T in the AARS2 gene was determined. The thymidine kinase 2 mutations resulted in severe mitochondrial DNA depletion (to 12% of controls) in the muscle. We present, for the first time, severe leucoencephalopathy and hepatic steatosis in a patient with thymidine kinase 2 deficiency and the finding of a ragged red fibre-like image in the muscle biopsy in a patient with alanyl-tRNA synthetase 2 deficiency.
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Alanina-ARNt Ligasa/deficiencia , Cardiomiopatía Hipertrófica/diagnóstico por imagen , ADN Mitocondrial/genética , Timidina Quinasa/deficiencia , Sustancia Blanca/diagnóstico por imagen , Alanina-ARNt Ligasa/genética , Autopsia , Cardiomiopatía Hipertrófica/genética , Ecocardiografía , Resultado Fatal , Femenino , Humanos , Lactante , Recién Nacido , Imagen por Resonancia Magnética , Enfermedades Mitocondriales/genética , Mutación , Timidina Quinasa/genéticaRESUMEN
The genetic cause of GAPO syndrome, a condition characterized by growth retardation, alopecia, pseudoanodontia, and progressive visual impairment, has not previously been identified. We studied four ethnically unrelated affected individuals and identified homozygous nonsense mutations (c.262C>T [p.Arg88*] and c.505C>T [p.Arg169*]) or splicing mutations (c.1435-12A>G [p.Gly479Phefs*119]) in ANTXR1, which encodes anthrax toxin receptor 1. The nonsense mutations predictably trigger nonsense-mediated mRNA decay, resulting in the loss of ANTXR1. The transcript with the splicing mutation theoretically encodes a truncated ANTXR1 containing a neopeptide composed of 118 unique amino acids in its C terminus. GAPO syndrome's major phenotypic features, which include dental abnormalities and the accumulation of extracellular matrix, recapitulate those found in Antxr1-mutant mice and point toward an underlying defect in extracellular-matrix regulation. Thus, we propose that mutations affecting ANTXR1 function are responsible for this disease's characteristic generalized defect in extracellular-matrix homeostasis.
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Alopecia/genética , Anodoncia/genética , Cromosomas Humanos Par 2/genética , Matriz Extracelular/genética , Predisposición Genética a la Enfermedad/genética , Trastornos del Crecimiento/genética , Homeostasis/genética , Proteínas de Neoplasias/genética , Atrofias Ópticas Hereditarias/genética , Receptores de Superficie Celular/genética , Alopecia/patología , Empalme Alternativo/genética , Anodoncia/patología , Secuencia de Bases , Codón sin Sentido/genética , Cartilla de ADN/genética , Matriz Extracelular/metabolismo , Fibroblastos , Técnica del Anticuerpo Fluorescente , Frecuencia de los Genes , Trastornos del Crecimiento/patología , Humanos , Masculino , Proteínas de Microfilamentos , Datos de Secuencia Molecular , Atrofias Ópticas Hereditarias/patología , Linaje , Sitios de Empalme de ARN/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADNRESUMEN
PURPOSE: Colorectal cancer is an important cause of mortality in the developed world. Hereditary forms are due to germ-line mutations in APC, MUTYH, and the mismatch repair genes, but many cases present familial aggregation but an unknown inherited cause. The hypothesis of rare high-penetrance mutations in new genes is a likely explanation for the underlying predisposition in some of these familial cases. METHODS: Exome sequencing was performed in 43 patients with colorectal cancer from 29 families with strong disease aggregation without mutations in known hereditary colorectal cancer genes. Data analysis selected only very rare variants (0-0.1%), producing a putative loss of function and located in genes with a role compatible with cancer. Variants in genes previously involved in hereditary colorectal cancer or nearby previous colorectal cancer genome-wide association study hits were also chosen. RESULTS: Twenty-eight final candidate variants were selected and validated by Sanger sequencing. Correct family segregation and somatic studies were used to categorize the most interesting variants in CDKN1B, XRCC4, EPHX1, NFKBIZ, SMARCA4, and BARD1. CONCLUSION: We identified new potential colorectal cancer predisposition variants in genes that have a role in cancer predisposition and are involved in DNA repair and the cell cycle, which supports their putative involvement in germ-line predisposition to this neoplasm.
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Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Neoplasias Colorrectales/genética , Exoma , Predisposición Genética a la Enfermedad , Variación Genética , Secuenciación de Nucleótidos de Alto Rendimiento , Asesoramiento Genético , Mutación de Línea Germinal , Humanos , Pérdida de Heterocigocidad , Masculino , Linaje , Reproducibilidad de los ResultadosRESUMEN
Inactivating mutations in the BCKDK gene, which codes for the kinase responsible for the negative regulation of the branched-chain α-keto acid dehydrogenase complex (BCKD), have recently been associated with a form of autism in three families. In this work, two novel exonic BCKDK mutations, c.520C>G/p.R174G and c.1166T>C/p.L389P, were identified at the homozygous state in two unrelated children with persistently reduced body fluid levels of branched-chain amino acids (BCAAs), developmental delay, microcephaly, and neurobehavioral abnormalities. Functional analysis of the mutations confirmed the missense character of the c.1166T>C change and showed a splicing defect r.[520c>g;521_543del]/p.R174Gfs1*, for c.520C>G due to the presence of a new donor splice site. Mutation p.L389P showed total loss of kinase activity. Moreover, patient-derived fibroblasts showed undetectable (p.R174Gfs1*) or barely detectable (p.L389P) levels of BCKDK protein and its phosphorylated substrate (phospho-E1α), resulting in increased BCKD activity and the very rapid BCAA catabolism manifested by the patients' clinical phenotype. Based on these results, a protein-rich diet plus oral BCAA supplementation was implemented in the patient homozygous for p.R174Gfs1*. This treatment normalized plasma BCAA levels and improved growth, developmental and behavioral variables. Our results demonstrate that BCKDK mutations can result in neurobehavioral deficits in humans and support the rationale for dietary intervention.
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Discapacidades del Desarrollo/genética , Enfermedades del Sistema Nervioso/genética , Proteínas Quinasas/genética , Aminoácidos de Cadena Ramificada/administración & dosificación , Aminoácidos de Cadena Ramificada/sangre , Discapacidades del Desarrollo/dietoterapia , Fibroblastos/enzimología , Humanos , Masculino , Mutación Missense , Enfermedades del Sistema Nervioso/dietoterapia , Pediatría , Proteínas Quinasas/deficienciaRESUMEN
Autosomal-dominant adult-onset neuronal ceroid lipofuscinosis (ANCL) is characterized by accumulation of autofluorescent storage material in neural tissues and neurodegeneration and has an age of onset in the third decade of life or later. The genetic and molecular basis of the disease has remained unknown for many years. We carried out linkage mapping, gene-expression analysis, exome sequencing, and candidate-gene sequencing in affected individuals from 20 families and/or individuals with simplex cases; we identified in five individuals one of two disease-causing mutations, c.346_348delCTC and c.344T>G, in DNAJC5 encoding cysteine-string protein alpha (CSPα). These mutations-causing a deletion, p.Leu116del, and an amino acid exchange, p.Leu115Arg, respectively-are located within the cysteine-string domain of the protein and affect both palmitoylation-dependent sorting and the amount of CSPα in neuronal cells. The resulting depletion of functional CSPα might cause in parallel the presynaptic dysfunction and the progressive neurodegeneration observed in affected individuals and lysosomal accumulation of misfolded and proteolysis-resistant proteins in the form of characteristic ceroid deposits in neurons. Our work represents an important step in the genetic dissection of a genetically heterogeneous group of ANCLs. It also confirms a neuroprotective role for CSPα in humans and demonstrates the need for detailed investigation of CSPα in the neuronal ceroid lipofuscinoses and other neurodegenerative diseases presenting with neuronal protein aggregation.
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Genes Dominantes/genética , Proteínas del Choque Térmico HSP40/genética , Proteínas de la Membrana/genética , Mutación/genética , Lipofuscinosis Ceroideas Neuronales/epidemiología , Lipofuscinosis Ceroideas Neuronales/genética , Adulto , Edad de Inicio , Secuencia de Bases , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/ultraestructura , Segregación Cromosómica/genética , Exones/genética , Familia , Femenino , Dosificación de Gen/genética , Regulación de la Expresión Génica , Ligamiento Genético , Humanos , Lipoilación , Lisosomas/metabolismo , Lisosomas/ultraestructura , Masculino , Datos de Secuencia Molecular , Lipofuscinosis Ceroideas Neuronales/patología , Neuronas/metabolismo , Neuronas/patología , Neuronas/ultraestructura , Linaje , Transporte de Proteínas , Análisis de Secuencia de ADNRESUMEN
In 2001, we reported linkage of an autosomal dominant form of limb-girdle muscular dystrophy, limb-girdle muscular dystrophy 1F, to chromosome 7q32.1-32.2, but the identity of the mutant gene was elusive. Here, using a whole genome sequencing strategy, we identified the causative mutation of limb-girdle muscular dystrophy 1F, a heterozygous single nucleotide deletion (c.2771del) in the termination codon of transportin 3 (TNPO3). This gene is situated within the chromosomal region linked to the disease and encodes a nuclear membrane protein belonging to the importin beta family. TNPO3 transports serine/arginine-rich proteins into the nucleus, and has been identified as a key factor in the HIV-import process into the nucleus. The mutation is predicted to generate a 15-amino acid extension of the C-terminus of the protein, segregates with the clinical phenotype, and is absent in genomic sequence databases and a set of >200 control alleles. In skeletal muscle of affected individuals, expression of the mutant messenger RNA and histological abnormalities of nuclei and TNPO3 indicate altered TNPO3 function. Our results demonstrate that the TNPO3 mutation is the cause of limb-girdle muscular dystrophy 1F, expand our knowledge of the molecular basis of muscular dystrophies and bolster the importance of defects of nuclear envelope proteins as causes of inherited myopathies.
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Eliminación de Gen , Distrofia Muscular de Cinturas/diagnóstico , Distrofia Muscular de Cinturas/genética , beta Carioferinas/genética , Adolescente , Adulto , Anciano , Secuencia de Bases , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Distrofia Muscular de Cinturas/metabolismo , Linaje , beta Carioferinas/biosíntesisRESUMEN
The genetic correlates of extreme impulsive violence are poorly understood, and there have been few studies that have characterized a large group of affected individuals both clinically and genetically. We performed whole exome sequencing (WES) in 290 males with the life-course-persistent, extremely impulsively violent form of antisocial personality disorder (APD) and analyzed the spectrum of rare protein-truncating variants (rPTVs). Comparisons were made with 314 male controls and publicly available genotype data. Functional annotation tools were used for biological interpretation. Participants were significantly more likely to harbor rPTVs in genes that are intolerant to loss-of-function variants (odds ratio [OR] 2.06; p < 0.001), specifically expressed in brain (OR 2.80; p = 0.036) and enriched for those involved in neurotransmitter transport and synaptic processes. In 60 individuals (20%), we identified rPTVs that we classified as clinically relevant based on their clinical associations, biological function and gene expression patterns. Of these, 37 individuals harbored rPTVs in 23 genes that are associated with a monogenic neurological disorder, and 23 individuals harbored rPTVs in 20 genes reportedly intolerant to loss-of-function variants. The analysis presents evidence in support of a model where presence of either one or several private, functionally relevant mutations contribute significantly to individual risk of life-course-persistent APD and reveals multiple individuals who could be affected by clinically unrecognized neuropsychiatric Mendelian disease. Thus, Mendelian diseases and increased rPTV burden may represent important factors for the development of extremely impulsive violent life-course-persistent forms of APD irrespective of their clinical presentation.
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Agresión , Trastorno de Personalidad Antisocial , Humanos , Masculino , Trastorno de Personalidad Antisocial/genética , Encéfalo , Violencia/psicología , GenotipoRESUMEN
Introduction: Monoallelic variants in the ALG5 gene encoding asparagine-linked glycosylation protein 5 homolog (ALG5) have been recently shown to disrupt polycystin-1 (PC1) maturation and trafficking via underglycosylation, causing an autosomal dominant polycystic kidney disease-like (ADPKD-like) phenotype and interstitial fibrosis. In this report, we present clinical, genetic, histopathologic, and protein structure and functional correlates of a new ALG5 variant, p.R79W, that we identified in 2 distant genetically related Irish families displaying an atypical late-onset ADPKD phenotype combined with tubulointerstitial damage. Methods: Whole exome and targeted sequencing were used for segregation analysis of available relatives. This was followed by immunohistochemistry examinations of kidney biopsies, and targeted (UMOD, MUC1) and untargeted plasma proteome and N-glycomic studies. Results: We identified a monoallelic ALG5 variant [GRCh37 (NM_013338.5): g.37569565G>A, c.235C>T; p.R79W] that cosegregates in 23 individuals, of whom 18 were clinically affected. We detected abnormal localization of ALG5 in the Golgi apparatus of renal tubular cells in patients' kidney specimens. Further, we detected the pathological accumulation of uromodulin, an N-glycosylated glycosylphosphatidylinositol (GPI)-anchored protein, in the endoplasmic reticulum (ER), but not mucin-1, an O- and N-glycosylated protein. Biochemical investigation revealed decreased plasma and urinary uromodulin levels in clinically affected individuals. Proteomic and glycoproteomic profiling revealed the dysregulation of chronic kidney disease (CKD)-associated proteins. Conclusion: ALG5 dysfunction adversely affects maturation and trafficking of N-glycosylated and GPI anchored protein uromodulin, leading to structural and functional changes in the kidney. Our findings confirm ALG5 as a cause of late-onset ADPKD and provide additional insight into the molecular mechanisms of ADPKD-ALG5.
RESUMEN
Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative disorder categorized into 3 phenotypic variants: infantile, juvenile, and adult. Four recent reports have linked NIID to CGG expansions in the NOTCH2NLC gene in adult NIID (aNIID) and several juvenile patients. Infantile NIID (iNIID) is an extremely rare neuropediatric condition. We present a 7-year-old male patient with severe progressive neurodegenerative disease that included cerebellar symptoms with cerebellar atrophy on brain MRI, psychomotor developmental regression, pseudobulbar syndrome, and polyneuropathy. The diagnosis of iNIID was established through a postmortem neuropathology work-up. We performed long-read sequencing of the critical NOTCH2NLC repeat motif and found no expansion in the patient. We also re-evaluated an antemortem skin biopsy that was collected when the patient was 2 years and 8 months old and did not identify the intranuclear inclusions. In our report, we highlight that the 2 methods (skin biopsy and CGG expansion testing in NOTCH2NLC) used to identify aNIID patients may provide negative results in iNIID patients.
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Enfermedades Neurodegenerativas/diagnóstico , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/patología , Receptor Notch2/genética , Biopsia , Encéfalo/patología , Niño , Preescolar , Humanos , Lactante , Recién Nacido , Cuerpos de Inclusión Intranucleares/genética , Cuerpos de Inclusión Intranucleares/patología , Masculino , Piel/patología , Médula Espinal/patología , Repeticiones de Trinucleótidos/genéticaRESUMEN
BACKGROUND: Spinal muscular atrophy (SMA) is an inherited neuromuscular disease affecting 1 in 8,000 newborns. The majority of patients carry bi-allelic variants in the survival of motor neuron 1 gene (SMN1). SMN1 is located in a duplicated region on chromosome 5q13 that contains Alu elements and is predisposed to genomic rearrangements. Due to the genomic complexity of the SMN region and genetic heterogeneity, approximately 50% of SMA patients remain without genetic diagnosis that is a prerequisite for genetic treatments. In this work we describe the diagnostic odyssey of one SMA patient in whom routine diagnostics identified only a maternal heterozygous SMN1Δ(7-8) deletion. METHODS: We characterized SMN transcripts, assessed SMN protein content in peripheral blood mononuclear cells (PBMC), estimated SMN genes dosage, and mapped genomic rearrangement in the SMN region. RESULTS: We identified an Alu-mediated deletion encompassing exons 2a-5 of SMN1 on the paternal allele and a complete deletion of SMN1 on the maternal allele as the cause of SMA in this patient. CONCLUSION: Alu-mediated rearrangements in SMN1 can escape routine diagnostic testing. Parallel analysis of SMN gene dosage, SMN transcripts, and total SMN protein levels in PBMC can identify genomic rearrangements and should be considered in genetically undefined SMA cases.
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Eliminación de Gen , Pruebas Genéticas/métodos , Atrofia Muscular Espinal/genética , Proteína 1 para la Supervivencia de la Neurona Motora/genética , Elementos Alu , Western Blotting/métodos , Preescolar , Femenino , Humanos , Leucocitos Mononucleares/metabolismo , Atrofia Muscular Espinal/diagnóstico , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN/métodos , Proteína 1 para la Supervivencia de la Neurona Motora/metabolismoRESUMEN
Adult-onset neuronal ceroid lipofuscinoses (ANCL, Kufs disease) are rare hereditary neuropsychiatric disorders characterized by intralysosomal accumulation of ceroid in tissues. The ceroid accumulation primarily affects the brain, leading to neuronal loss and progressive neurodegeneration. Although several causative genes have been identified (DNAJC5, CLN6, CTSF, GRN, CLN1, CLN5, ATP13A2), the genetic underpinnings of ANCL in some families remain unknown. Here we report one family with autosomal dominant (AD) Kufs disease caused by a 30 bp in-frame duplication in DNAJC5, encoding the cysteine-string protein alpha (CSPα). This variant leads to a duplication of the central core motif of the cysteine-string domain of CSPα and affects palmitoylation-dependent CSPα sorting in cultured neuronal cells similarly to two previously described CSPα variants, p.(Leu115Arg) and p.(Leu116del). Interestingly, the duplication was not detected initially by standard Sanger sequencing due to a preferential PCR amplification of the shorter wild-type allele and allelic dropout of the mutated DNAJC5 allele. It was also missed by subsequent whole-exome sequencing (WES). Its identification was facilitated by reanalysis of original WES data and modification of the PCR and Sanger sequencing protocols. Independently occurring variants in the genomic sequence of DNAJC5 encoding the cysteine-string domain of CSPα suggest that this region may be more prone to DNA replication errors and that insertions or duplications within this domain should be considered in unsolved ANCL cases.
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Duplicación de Gen , Proteínas del Choque Térmico HSP40/genética , Proteínas de la Membrana/genética , Lipofuscinosis Ceroideas Neuronales/genética , Adulto , Animales , Línea Celular , Reacciones Falso Negativas , Femenino , Pruebas Genéticas/normas , Proteínas del Choque Térmico HSP40/metabolismo , Humanos , Masculino , Proteínas de la Membrana/metabolismo , Ratones , Persona de Mediana Edad , Lipofuscinosis Ceroideas Neuronales/patología , Neuronas/metabolismo , Procesamiento Proteico-Postraduccional , Transporte de Proteínas , Secuenciación Completa del Genoma/normasRESUMEN
The genetic correlates of extreme impulsive violence are poorly understood, and there have been no studies that have systematically characterized a large group of affected individuals both clinically and genetically. We performed a genome-wide rare copy number variant (CNV) analysis in 281 males from four Czech prisons who met strict clinical criteria for extreme impulsive violence. Inclusion criteria included age ≥ 18 years, an ICD-10 diagnosis of Dissocial Personality Disorder, and the absence of an organic brain disorder. Participants underwent a structured psychiatric assessment to diagnose extreme impulsive violence and then provided a blood sample for genetic analysis. DNA was genotyped and CNVs were identified using Illumina HumanOmni2.5 single-nucleotide polymorphism array platform. Comparing with 10851 external population controls, we identified 828 rare CNVs (frequency ≤ 0.1% among control samples) in 264 participants. The CNVs impacted 754 genes, with 124 genes impacted more than once (2-25 times). Many of these genes are associated with autosomal dominant or X-linked disorders affecting adult behavior, cognition, learning, intelligence, specifically expressed in the brain and relevant to synapses, neurodevelopment, neurodegeneration, obesity and neuropsychiatric phenotypes. Specifically, we identified 31 CNVs of clinical relevance in 31 individuals, 59 likely clinically relevant CNVs in 49 individuals, and 17 recurrent CNVs in 65 individuals. Thus, 123 of 281 (44%) individuals had one to several rare CNVs that were indirectly or directly relevant to impulsive violence. Extreme impulsive violence is genetically heterogeneous and genomic analysis is likely required to identify, further research and specifically treat the causes in affected individuals.
Asunto(s)
Trastorno de Personalidad Antisocial/genética , Variaciones en el Número de Copia de ADN , Conducta Impulsiva , Violencia , Adolescente , Adulto , Anciano , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: The progressive myoclonic epilepsies (PME) are a heterogeneous group of disorders in which a specific diagnosis cannot be made in a subset of patients, despite exhaustive investigation. C9orf72 repeat expansions are emerging as an important causal factor in several adult-onset neurodegenerative disorders, in particular frontotemporal lobar degeneration and amyotrophic lateral sclerosis. An association with PME has not been reported previously. OBJECTIVE: To identify the causative mutation in a Belgian family where the proband had genetically unexplained PME. RESULTS: We report a 33-year old woman who had epilepsy since the age of 15 and then developed progressive cognitive deterioration and multifocal myoclonus at the age of 18. The family history suggested autosomal dominant inheritance of psychiatric disorders, epilepsy, and dementia. Thorough workup for PME including whole exome sequencing did not reveal an underlying cause, but a C9orf72 repeat expansion was found in our patient and affected relatives. Brain biopsy confirmed the presence of characteristic p62-positive neuronal cytoplasmic inclusions. CONCLUSION: C9orf72 mutation analysis should be considered in patients with PME and psychiatric disorders or dementia, even when the onset is in late childhood or adolescence.
Asunto(s)
Proteína C9orf72/genética , Expansión de las Repeticiones de ADN , Epilepsias Mioclónicas Progresivas/genética , Adulto , Edad de Inicio , Encéfalo/patología , Familia , Femenino , Predisposición Genética a la Enfermedad , Humanos , Persona de Mediana Edad , Epilepsias Mioclónicas Progresivas/patología , Epilepsias Mioclónicas Progresivas/fisiopatología , Epilepsias Mioclónicas Progresivas/psicología , Linaje , FenotipoRESUMEN
The formation of the vertebrate brain requires the generation, migration, differentiation and survival of neurons. Genetic mutations that perturb these critical cellular events can result in malformations of the telencephalon, providing a molecular window into brain development. Here we report the identification of an N-ethyl-N-nitrosourea-induced mouse mutant characterized by a fractured hippocampal pyramidal cell layer, attributable to defects in neuronal migration. We show that this is caused by a hypomorphic mutation in Vps15 that perturbs endosomal-lysosomal trafficking and autophagy, resulting in an upregulation of Nischarin, which inhibits Pak1 signaling. The complete ablation of Vps15 results in the accumulation of autophagic substrates, the induction of apoptosis and severe cortical atrophy. Finally, we report that mutations in VPS15 are associated with cortical atrophy and epilepsy in humans. These data highlight the importance of the Vps15-Vps34 complex and the Nischarin-Pak1 signaling hub in the development of the telencephalon.
Asunto(s)
Movimiento Celular/genética , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Mutación/efectos de los fármacos , Trastornos del Neurodesarrollo , Neuronas/patología , ATPasas de Translocación de Protón Vacuolares/genética , Alquilantes/toxicidad , Animales , Animales Recién Nacidos , Atrofia/inducido químicamente , Atrofia/genética , Atrofia/patología , Autofagia/efectos de los fármacos , Autofagia/genética , Encéfalo/efectos de los fármacos , Encéfalo/patología , Movimiento Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Embrión de Mamíferos , Etilnitrosourea/toxicidad , Femenino , Regulación del Desarrollo de la Expresión Génica/genética , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Trastornos del Neurodesarrollo/inducido químicamente , Trastornos del Neurodesarrollo/diagnóstico por imagen , Trastornos del Neurodesarrollo/genética , Trastornos del Neurodesarrollo/patología , Neuronas/efectos de los fármacos , Neuronas/ultraestructura , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , ATPasas de Translocación de Protón Vacuolares/efectos de los fármacosRESUMEN
In the supplementary information PDF originally posted, there were discrepancies from the integrated supplementary information that appeared in the HTML; the former has been corrected as follows. In the legend to Supplementary Fig. 2c, "major organs of the mouse" has been changed to "major organs of the adult mouse." In the legend to Supplementary Fig. 6d,h, "At E14.5 Mbe/Mbe mutants have a smaller percentage of Brdu positive cells in bin 3" has been changed to "At E14.5 Mbe/Mbe mutants have a higher percentage of Brdu positive cells in bin 3."