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1.
Neuro Oncol ; 21(10): 1273-1283, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31222332

RESUMO

BACKGROUND: Medical treatment in Cushing's disease (CD) is limited due to poor understanding of its pathogenesis. Pathogenic variants of ubiquitin specific peptidase 8 (USP8) have been confirmed as causative in around half of corticotroph tumors. We aimed to further characterize the molecular landscape of those CD tumors lacking USP8 mutations in a large cohort of patients. METHODS: Exome sequencing was performed on 18 paired tumor-blood samples with wild-type USP8 status. Candidate gene variants were screened by Sanger sequencing in 175 additional samples. The most frequent variant was characterized by further functional in vitro assays. RESULTS: Recurrent somatic hotspot mutations in another deubiquitinase, USP48, were found in 10.3% of analyzed samples. Several possibly damaging variants were found in TP53 in 6 of 18 samples. USP48 variants were associated with smaller tumors and trended toward higher frequency in female patients. They also changed the structural conformation of USP48 and increased its catalytic activity toward its physiological substrates histone 2A and zinc finger protein Gli1, as well as enhanced the stimulatory effect of corticotropin releasing hormone (CRH) on pro-opiomelanocortin production and adrenocorticotropic hormone secretion. CONCLUSIONS: USP48 pathogenic variants are relatively frequent in USP8 wild-type tumors and enhance CRH-induced hormone production in a manner coherent with sonic hedgehog activation. In addition, TP53 pathogenic variants may be more frequent in larger CD tumors than previously reported.

2.
J Inherit Metab Dis ; 42(5): 909-917, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31059585

RESUMO

Diagnostics for suspected mitochondrial disease (MD) can be challenging and necessitate invasive procedures like muscle biopsy. This is due to the extremely broad genetic and phenotypic spectrum, disease genes on both nuclear and mitochondrial DNA (mtDNA), and the tissue specificity of mtDNA variants. Exome sequencing (ES) has revolutionized the diagnostics for MD. However, the nuclear and mtDNA are investigated with separate tests, increasing costs and duration of diagnostics. The full potential of ES is often not exploited as the additional analysis of "off-target reads" deriving from the mtDNA can be used to analyze both genomes. We performed mtDNA analysis by ES of 2111 cases in a clinical setting. We further assessed the recall rate and precision as well as the estimation of heteroplasmy by ES data by comparison with targeted mtDNA next generation sequencing in 49 cases. ES identified known pathogenic mtDNA point mutations in 38 individuals, increasing the diagnostic yield by nearly 2%. Analysis of mtDNA variants by ES had a high recall rate (96.2 ± 5.6%) and an excellent precision (99.5 ± 2.2%) when compared to the gold standard of targeted mtDNA next generation sequencing. ES estimated heteroplasmy levels with an average difference of 6.6 ± 3.8%, sufficient for clinical decision making. Taken together, the mtDNA analysis from ES is of sufficient quality for clinical diagnostics. We therefore propose ES, investigating both nuclear and mtDNA, as first line test in individuals with suspected MD. One should be aware, that a negative result does not exclude MD and necessitates further test (in additional tissues).

3.
Clin Genet ; 95(5): 582-589, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30868567

RESUMO

Congenital heart defects (CHDs) are the most common birth defect with 30%-40% being explained by genetic aberrations. With next generation sequencing becoming widely available, we sought to evaluate the clinical utility of exome sequencing (ES) in prenatally diagnosed CHD. We retrospectively analyzed the diagnostic yield as well as non-conclusive and incidental findings in 30 cases with prenatally diagnosed CHDs using ES, mostly as parent-child trios. A genetic diagnosis was established in 20% (6/30). Non-conclusive results were found in 13% (4/30) and incidental findings in 10% (3/30). There was a phenotypic discrepancy between reported prenatal and postnatal extracardiac findings in 40% (8/20). However, none of these additional, postnatal findings altered the genetic diagnosis. Herein, ES in prenatally diagnosed CHDs results in a comparably high diagnostic yield. There was a significant proportion of incidental findings and variants of unknown significance as well as potentially pathogenic variants in novel disease genes. Such findings can bedevil genetic counseling and decision making for pregnancy termination. Despite the small cohort size, our data serve as a first basis to evaluate the value of prenatal ES in CHD for further studies emerging in the near future.

4.
Nat Commun ; 10(1): 963, 2019 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-30814501

RESUMO

Aging promotes lung function decline and susceptibility to chronic lung diseases, which are the third leading cause of death worldwide. Here, we use single cell transcriptomics and mass spectrometry-based proteomics to quantify changes in cellular activity states across 30 cell types and chart the lung proteome of young and old mice. We show that aging leads to increased transcriptional noise, indicating deregulated epigenetic control. We observe cell type-specific effects of aging, uncovering increased cholesterol biosynthesis in type-2 pneumocytes and lipofibroblasts and altered relative frequency of airway epithelial cells as hallmarks of lung aging. Proteomic profiling reveals extracellular matrix remodeling in old mice, including increased collagen IV and XVI and decreased Fraser syndrome complex proteins and collagen XIV. Computational integration of the aging proteome with the single cell transcriptomes predicts the cellular source of regulated proteins and creates an unbiased reference map of the aging lung.


Assuntos
Envelhecimento/genética , Envelhecimento/metabolismo , Pulmão/metabolismo , Envelhecimento/patologia , Animais , Colesterol/biossíntese , Colágeno/metabolismo , Células Epiteliais/metabolismo , Matriz Extracelular/metabolismo , Perfilação da Expressão Gênica , Pulmão/citologia , Camundongos , Camundongos Endogâmicos C57BL , Proteoma/metabolismo , Proteômica , Análise de Célula Única
5.
Am J Physiol Endocrinol Metab ; 316(5): E866-E879, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30620635

RESUMO

Intermuscular adipose tissue (IMAT) is negatively related to insulin sensitivity, but a causal role of IMAT in the development of insulin resistance is unknown. IMAT was sampled in humans to test for the ability to induce insulin resistance in vitro and characterize gene expression to uncover how IMAT may promote skeletal muscle insulin resistance. Human primary muscle cells were incubated with conditioned media from IMAT, visceral (VAT), or subcutaneous adipose tissue (SAT) to evaluate changes in insulin sensitivity. RNAseq analysis was performed on IMAT with gene expression compared with skeletal muscle and SAT, and relationships to insulin sensitivity were determined in men and women spanning a wide range of insulin sensitivity measured by hyperinsulinemic-euglycemic clamp. Conditioned media from IMAT and VAT decreased insulin sensitivity similarly compared with SAT. Multidimensional scaling analysis revealed distinct gene expression patterns in IMAT compared with SAT and muscle. Pathway analysis revealed that IMAT expression of genes in insulin signaling, oxidative phosphorylation, and peroxisomal metabolism related positively to donor insulin sensitivity, whereas expression of macrophage markers, inflammatory cytokines, and secreted extracellular matrix proteins were negatively related to insulin sensitivity. Perilipin 5 gene expression suggested greater IMAT lipolysis in insulin-resistant individuals. Combined, these data show that factors secreted from IMAT modulate muscle insulin sensitivity, possibly via secretion of inflammatory cytokines and extracellular matrix proteins, and by increasing local FFA concentration in humans. These data suggest IMAT may be an important regulator of skeletal muscle insulin sensitivity and could be a novel therapeutic target for skeletal muscle insulin resistance.

6.
Am J Hum Genet ; 103(5): 817-825, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30401461

RESUMO

ADP-ribosylation is a reversible posttranslational modification used to regulate protein function. ADP-ribosyltransferases transfer ADP-ribose from NAD+ to the target protein, and ADP-ribosylhydrolases, such as ADPRHL2, reverse the reaction. We used exome sequencing to identify five different bi-allelic pathogenic ADPRHL2 variants in 12 individuals from 8 families affected by a neurodegenerative disorder manifesting in childhood or adolescence with key clinical features including developmental delay or regression, seizures, ataxia, and axonal (sensori-)motor neuropathy. ADPRHL2 was virtually absent in available affected individuals' fibroblasts, and cell viability was reduced upon hydrogen peroxide exposure, although it was rescued by expression of wild-type ADPRHL2 mRNA as well as treatment with a PARP1 inhibitor. Our findings suggest impaired protein ribosylation as another pathway that, if disturbed, causes neurodegenerative diseases.

7.
JIMD Rep ; 2018 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-29923093

RESUMO

SLC25A42 is an inner mitochondrial membrane protein which has been shown to transport coenzyme A through a lipid bilayer in vitro. A homozygous missense variant in this gene has been recently reported in 13 subjects of Arab descent presenting with mitochondriopathy with variable clinical manifestations. By exome sequencing, we identified two additional individuals carrying rare variants in this gene. One subject was found to carry the previously reported missense variant in homozygous state, while the second subject carried a homozygous canonical splice site variant resulting in a splice defect. With the identification of two additional cases, we corroborate the association between rare variants in SLC25A42 and a clinical presentation characterized by myopathy, developmental delay, lactic acidosis, and encephalopathy. Furthermore, we highlight the biochemical consequences of the splice defect by measuring a mild decrease of coenzyme A content in SLC25A42-mutant fibroblasts.

8.
Cell Rep ; 23(10): 3112-3125, 2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29874595

RESUMO

Activation and recruitment of thermogenic cells in human white adipose tissues ("browning") can counteract obesity and associated metabolic disorders. However, quantifying the effects of therapeutic interventions on browning remains enigmatic. Here, we devise a computational tool, named ProFAT (profiling of fat tissue types), for quantifying the thermogenic potential of heterogeneous fat biopsies based on prediction of white and brown adipocyte content from raw gene expression datasets. ProFAT systematically integrates 103 mouse-fat-derived transcriptomes to identify unbiased and robust gene signatures of brown and white adipocytes. We validate ProFAT on 80 mouse and 97 human transcriptional profiles from 14 independent studies and correctly predict browning capacity upon various physiological and pharmacological stimuli. Our study represents the most exhaustive comparative analysis of public data on adipose biology toward quantification of browning after personalized medical intervention. ProFAT is freely available and should become increasingly powerful with the growing wealth of transcriptomics data.

9.
EMBO J ; 37(12)2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29764980

RESUMO

Cell-cell and cell-matrix interactions guide organ development and homeostasis by controlling lineage specification and maintenance, but the underlying molecular principles are largely unknown. Here, we show that in human developing cardiomyocytes cell-cell contacts at the intercalated disk connect to remodeling of the actin cytoskeleton by regulating the RhoA-ROCK signaling to maintain an active MRTF/SRF transcriptional program essential for cardiomyocyte identity. Genetic perturbation of this mechanosensory pathway activates an ectopic fat gene program during cardiomyocyte differentiation, which ultimately primes the cells to switch to the brown/beige adipocyte lineage in response to adipogenesis-inducing signals. We also demonstrate by in vivo fate mapping and clonal analysis of cardiac progenitors that cardiac fat and a subset of cardiac muscle arise from a common precursor expressing Isl1 and Wt1 during heart development, suggesting related mechanisms of determination between the two lineages.

10.
Cell Metab ; 26(4): 620-632.e6, 2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28943448

RESUMO

Chronic inflammation has been proposed to contribute to the pathogenesis of diet-induced obesity. However, scarce therapeutic options are available to treat obesity and the associated immunometabolic complications. Glucocorticoids are routinely employed for the management of inflammatory diseases, but their pleiotropic nature leads to detrimental metabolic side effects. We developed a glucagon-like peptide-1 (GLP-1)-dexamethasone co-agonist in which GLP-1 selectively delivers dexamethasone to GLP-1 receptor-expressing cells. GLP-1-dexamethasone lowers body weight up to 25% in obese mice by targeting the hypothalamic control of feeding and by increasing energy expenditure. This strategy reverses hypothalamic and systemic inflammation while improving glucose tolerance and insulin sensitivity. The selective preference for GLP-1 receptor bypasses deleterious effects of dexamethasone on glucose handling, bone integrity, and hypothalamus-pituitary-adrenal axis activity. Thus, GLP-1-directed glucocorticoid pharmacology represents a safe and efficacious therapy option for diet-induced immunometabolic derangements and the resulting obesity.


Assuntos
Dexametasona/uso terapêutico , Peptídeo 1 Semelhante ao Glucagon/uso terapêutico , Glucocorticoides/uso terapêutico , Incretinas/uso terapêutico , Inflamação/tratamento farmacológico , Obesidade/tratamento farmacológico , Animais , Peso Corporal/efeitos dos fármacos , Dexametasona/análogos & derivados , Metabolismo Energético/efeitos dos fármacos , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Glucocorticoides/química , Glucose/metabolismo , Células HEK293 , Humanos , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Incretinas/química , Inflamação/complicações , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/complicações , Obesidade/metabolismo
11.
Cell Metab ; 26(2): 437-446.e5, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28768181

RESUMO

Brown adipose tissue (BAT)-dependent thermogenesis and its suggested augmenting hormone, FGF21, are potential therapeutic targets in current obesity and diabetes research. Here, we studied the role of UCP1 and FGF21 for metabolic homeostasis in the cold and dissected underlying molecular mechanisms using UCP1-FGF21 double-knockout mice. We report that neither UCP1 nor FGF21, nor even compensatory increases of FGF21 serum levels in UCP1 knockout mice, are required for defense of body temperature or for maintenance of energy metabolism and body weight. Remarkably, cold-induced browning of inguinal white adipose tissue (iWAT) is FGF21 independent. Global RNA sequencing reveals major changes in response to UCP1- but not FGF21-ablation in BAT, iWAT, and muscle. Markers of mitochondrial failure and inflammation are observed in BAT, but in particular the enhanced metabolic reprogramming in iWAT supports the thermogenic role of UCP1 and excludes an important thermogenic role of endogenous FGF21 in normal cold acclimation.


Assuntos
Aclimatação/fisiologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Temperatura Baixa , Fatores de Crescimento de Fibroblastos/metabolismo , Termogênese/fisiologia , Proteína Desacopladora 1/metabolismo , Tecido Adiposo Marrom/citologia , Tecido Adiposo Branco/citologia , Animais , Fatores de Crescimento de Fibroblastos/genética , Camundongos , Camundongos Knockout , Proteína Desacopladora 1/genética
12.
Pediatr Res ; 82(5): 753-758, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28665926

RESUMO

BackgroundOsteogenesis imperfecta (OI) is a heritable bone fragility disorder usually caused by dominant variants in COL1A1 or COL1A2 genes. Over the last few years, 17 genes including 12 autosomal recessive and five autosomal dominant forms of OI, involved in various aspects of bone formation, have been identified.MethodsWhole-exome sequencing followed by conventional Sanger sequencing was performed in a single affected individual (IV-3) in a family.ResultsHere, we report the clinical and genetic characterization of OI type 3 in a consanguineous family with four affected members. Clinical examinations revealed low bone density, short stature, severe vertebral compression fractures, and multiple long bone fractures in the affected members. Exome sequencing revealed a biallelic pathogenic splice acceptor site variant (c.359-3C>G) in a wingless-type mouse mammary tumor virus integration site family 1 (WNT1) gene located on chromosome 12q13.12.ConclusionWe report a biallelic splice site variant underlying OI type 3 and the first case from the Pakistani population.


Assuntos
Análise Mutacional de DNA/métodos , Homozigoto , Mutação , Osteogênese Imperfeita/genética , Sítios de Splice de RNA , Sequenciamento Completo do Exoma , Proteína Wnt1/genética , Adolescente , Criança , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Hereditariedade , Humanos , Masculino , Osteogênese Imperfeita/complicações , Osteogênese Imperfeita/diagnóstico por imagem , Paquistão , Linhagem , Fenótipo
13.
Nat Commun ; 8: 15824, 2017 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-28604674

RESUMO

Across a variety of Mendelian disorders, ∼50-75% of patients do not receive a genetic diagnosis by exome sequencing indicating disease-causing variants in non-coding regions. Although genome sequencing in principle reveals all genetic variants, their sizeable number and poorer annotation make prioritization challenging. Here, we demonstrate the power of transcriptome sequencing to molecularly diagnose 10% (5 of 48) of mitochondriopathy patients and identify candidate genes for the remainder. We find a median of one aberrantly expressed gene, five aberrant splicing events and six mono-allelically expressed rare variants in patient-derived fibroblasts and establish disease-causing roles for each kind. Private exons often arise from cryptic splice sites providing an important clue for variant prioritization. One such event is found in the complex I assembly factor TIMMDC1 establishing a novel disease-associated gene. In conclusion, our study expands the diagnostic tools for detecting non-exonic variants and provides examples of intronic loss-of-function variants with pathological relevance.


Assuntos
Perfilação da Expressão Gênica , Doenças Mitocondriais/genética , Análise de Sequência de RNA , Técnicas e Procedimentos Diagnósticos , Humanos , Processamento de RNA
14.
Eur J Hum Genet ; 25(8): 960-965, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28488682

RESUMO

Polydactyly is characterized by an extra supernumerary digit/toe with or without bony element. To date variants in four genes GLI3, ZNF141, MIPOL1 and PITX1 have been implicated in developing non-syndromic form of polydactyly. The present study involved characterization of large consanguineous family of Pakistani origin segregating post-axial polydactyly type A, restricted to lower limb, in autosomal recessive pattern. DNA of two affected members in the family was subjected to exome sequencing. Sanger sequencing was then followed to validate segregation of the variants in the family members. A homozygous splice acceptor site variant (c.395-1G>A) was identified in the IQCE gene, which completely co-segregated with post-axial polydactyly phenotype within the family. The homozygous variant was absent in different public variant databases, 7000 in-house exomes, 130 exomes from unrelated Pakistani individuals and 215 ethnically matched controls. Mini-gene splicing assay was used to test effect of the variant on function of the gene. The assay revealed loss of first nucleotide of exon 6, producing a -1 frameshift and a premature stop codon 22 bases downstream of the variant (p.Gly132Valfs*22). The study provided the first evidence of involvement of the IQCE gene in limbs development in humans.


Assuntos
Exoma , Mutação da Fase de Leitura , Peptídeos e Proteínas de Sinalização Intracelular/genética , Polidactilia/genética , Dedos do Pé/anormalidades , Alelos , Códon de Terminação , Feminino , Células HeLa , Homozigoto , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Linhagem , Fenótipo , Polidactilia/diagnóstico
15.
Eur J Hum Genet ; 25(2): 183-191, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27901041

RESUMO

Truncating ASXL3 mutations were first identified in 2013 by Bainbridge et al. as a cause of syndromic intellectual disability in four children with similar phenotypes using whole-exome sequencing. The clinical features - postulated by Bainbridge et al. to be overlapping with Bohring-Opitz syndrome - were developmental delay, severe feeding difficulties, failure to thrive and neurological abnormalities. This condition was included in OMIM as 'Bainbridge-Ropers syndrome' (BRPS, #615485). To date, a total of nine individuals with BRPS have been published in the literature in four reports (Bainbridge et al., Dinwiddie et al, Srivastava et al. and Hori et al.). In this report, we describe six unrelated patients with newly diagnosed heterozygous de novo loss-of-function variants in ASXL3 and concordant clinical features: severe muscular hypotonia with feeding difficulties in infancy, significant motor delay, profound speech impairment, intellectual disability and a characteristic craniofacial phenotype (long face, arched eyebrows with mild synophrys, downslanting palpebral fissures, prominent columella, small alae nasi, high, narrow palate and relatively little facial expression). The majority of key features characteristic for Bohring-Opitz syndrome were absent in our patients (eg, the typical posture of arms, intrauterine growth retardation, microcephaly, trigonocephaly, typical facial gestalt with nevus flammeus of the forehead and exophthalmos). Therefore we emphasize that BRPS syndrome, caused by ASXL3 loss-of-function variants, is a clinically distinct intellectual disability syndrome with a recognizable phenotype distinguishable from that of Bohring-Opitz syndrome.


Assuntos
Deficiências do Desenvolvimento/genética , Insuficiência de Crescimento/genética , Fatores de Transcrição/genética , Adolescente , Pré-Escolar , Deficiências do Desenvolvimento/diagnóstico , Insuficiência de Crescimento/diagnóstico , Feminino , Humanos , Lactente , Masculino , Mutação , Fenótipo , Síndrome
16.
Am J Hum Genet ; 99(3): 735-743, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27545679

RESUMO

SQSTM1 (sequestosome 1; also known as p62) encodes a multidomain scaffolding protein involved in various key cellular processes, including the removal of damaged mitochondria by its function as a selective autophagy receptor. Heterozygous variants in SQSTM1 have been associated with Paget disease of the bone and might contribute to neurodegeneration in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Using exome sequencing, we identified three different biallelic loss-of-function variants in SQSTM1 in nine affected individuals from four families with a childhood- or adolescence-onset neurodegenerative disorder characterized by gait abnormalities, ataxia, dysarthria, dystonia, vertical gaze palsy, and cognitive decline. We confirmed absence of the SQSTM1/p62 protein in affected individuals' fibroblasts and found evidence of a defect in the early response to mitochondrial depolarization and autophagosome formation. Our findings expand the SQSTM1-associated phenotypic spectrum and lend further support to the concept of disturbed selective autophagy pathways in neurodegenerative diseases.


Assuntos
Ataxia/genética , Autofagia/genética , Distonia/genética , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/fisiopatologia , Proteína Sequestossoma-1/deficiência , Paralisia Supranuclear Progressiva/genética , Adolescente , Adulto , Idade de Início , Ataxia/complicações , Autofagossomos/metabolismo , Autofagossomos/patologia , Criança , Transtornos Cognitivos/genética , Disartria/complicações , Disartria/genética , Distonia/complicações , Feminino , Fibroblastos/metabolismo , Marcha/genética , Humanos , Masculino , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Transtornos dos Movimentos/complicações , Transtornos dos Movimentos/genética , Doenças Neurodegenerativas/complicações , Linhagem , Fenótipo , RNA Mensageiro/análise , Proteína Sequestossoma-1/genética , Paralisia Supranuclear Progressiva/complicações , Adulto Jovem
17.
Am J Hum Genet ; 98(6): 1130-1145, 2016 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-27259049

RESUMO

Multiple acyl-CoA dehydrogenase deficiencies (MADDs) are a heterogeneous group of metabolic disorders with combined respiratory-chain deficiency and a neuromuscular phenotype. Despite recent advances in understanding the genetic basis of MADD, a number of cases remain unexplained. Here, we report clinically relevant variants in FLAD1, which encodes FAD synthase (FADS), as the cause of MADD and respiratory-chain dysfunction in nine individuals recruited from metabolic centers in six countries. In most individuals, we identified biallelic frameshift variants in the molybdopterin binding (MPTb) domain, located upstream of the FADS domain. Inasmuch as FADS is essential for cellular supply of FAD cofactors, the finding of biallelic frameshift variants was unexpected. Using RNA sequencing analysis combined with protein mass spectrometry, we discovered FLAD1 isoforms, which only encode the FADS domain. The existence of these isoforms might explain why affected individuals with biallelic FLAD1 frameshift variants still harbor substantial FADS activity. Another group of individuals with a milder phenotype responsive to riboflavin were shown to have single amino acid changes in the FADS domain. When produced in E. coli, these mutant FADS proteins resulted in impaired but detectable FADS activity; for one of the variant proteins, the addition of FAD significantly improved protein stability, arguing for a chaperone-like action similar to what has been reported in other riboflavin-responsive inborn errors of metabolism. In conclusion, our studies identify FLAD1 variants as a cause of potentially treatable inborn errors of metabolism manifesting with MADD and shed light on the mechanisms by which FADS ensures cellular FAD homeostasis.


Assuntos
Mutação da Fase de Leitura/genética , Doenças Mitocondriais/genética , Deficiência Múltipla de Acil Coenzima A Desidrogenase/genética , Nucleotidiltransferases/genética , Riboflavina/farmacologia , Complexo Vitamínico B/farmacologia , Adulto , Western Blotting , Estudos de Casos e Controles , Células Cultivadas , Transporte de Elétrons , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/patologia , Flavina-Adenina Dinucleotídeo/metabolismo , Perfilação da Expressão Gênica , Humanos , Lactente , Recém-Nascido , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Doenças Mitocondriais/tratamento farmacológico , Doenças Mitocondriais/patologia , Deficiência Múltipla de Acil Coenzima A Desidrogenase/tratamento farmacológico , Deficiência Múltipla de Acil Coenzima A Desidrogenase/patologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Mutagênese Sítio-Dirigida , Ligação Proteica , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto Jovem
18.
Am J Hum Genet ; 98(2): 358-62, 2016 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-26805782

RESUMO

Molecular diagnosis of mitochondrial disorders is challenging because of extreme clinical and genetic heterogeneity. By exome sequencing, we identified three different bi-allelic truncating mutations in TANGO2 in three unrelated individuals with infancy-onset episodic metabolic crises characterized by encephalopathy, hypoglycemia, rhabdomyolysis, arrhythmias, and laboratory findings suggestive of a defect in mitochondrial fatty acid oxidation. Over the course of the disease, all individuals developed global brain atrophy with cognitive impairment and pyramidal signs. TANGO2 (transport and Golgi organization 2) encodes a protein with a putative function in redistribution of Golgi membranes into the endoplasmic reticulum in Drosophila and a mitochondrial localization has been confirmed in mice. Investigation of palmitate-dependent respiration in mutant fibroblasts showed evidence of a functional defect in mitochondrial ß-oxidation. Our results establish TANGO2 deficiency as a clinically recognizable cause of pediatric disease with multi-organ involvement.


Assuntos
Alelos , Arritmias Cardíacas/genética , Cardiomiopatias/genética , Mutação , Arritmias Cardíacas/diagnóstico , Cardiomiopatias/diagnóstico , Pré-Escolar , Exoma , Feminino , Humanos , Lactente , Masculino , Mitocôndrias/genética , Mitocôndrias/metabolismo , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/genética , Linhagem
19.
Mamm Genome ; 27(3-4): 111-21, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26803617

RESUMO

We performed exome sequencing for mutation discovery of an ENU (N-ethyl-N-nitrosourea)-derived mouse model characterized by significant elevated plasma alkaline phosphatase (ALP) activities in female and male mutant mice, originally named BAP014 (bone screen alkaline phosphatase #14). We identified a novel loss-of-function mutation within the Fam46a (family with sequence similarity 46, member A) gene (NM_001160378.1:c.469G>T, NP_001153850.1:p.Glu157*). Heterozygous mice of this mouse line (renamed Fam46a (E157*Mhda)) had significantly high ALP activities and apparently no other differences in morphology compared to wild-type mice. In contrast, homozygous Fam46a (E157*Mhda) mice showed severe morphological and skeletal abnormalities including short stature along with limb, rib, pelvis, and skull deformities with minimal trabecular bone and reduced cortical bone thickness in long bones. ALP activities of homozygous mutants were almost two-fold higher than in heterozygous mice. Fam46a is weakly expressed in most adult and embryonic tissues with a strong expression in mineralized tissues as calvaria and femur. The FAM46A protein is computationally predicted as a new member of the superfamily of nucleotidyltransferase fold proteins, but little is known about its function. Fam46a (E157*Mhda) mice are the first mouse model for a mutation within the Fam46a gene.


Assuntos
Doenças do Desenvolvimento Ósseo/genética , Doenças do Desenvolvimento Ósseo/patologia , Códon sem Sentido , Exoma , Fosfatase Alcalina/metabolismo , Animais , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Análise Mutacional de DNA , Modelos Animais de Doenças , Ativação Enzimática , Feminino , Expressão Gênica , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Masculino , Camundongos , Camundongos Knockout , Fenótipo
20.
Gerontologist ; 56(6): 1124-1137, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-26035877

RESUMO

PURPOSE OF THE STUDY: This substudy of the Swiss Nursing Homes Human Resources Project (SHURP) explored the relationships between affective organizational commitment (AOC) levels and organizational, situational, and care personnel characteristics, and between AOC and care personnel outcomes. DESIGNS AND METHODS: SHURP was a representative national cross-sectional study in 163 Swiss nursing homes. Its data sources were: (a) a care personnel questionnaire, (b) a facility questionnaire, (c) a unit questionnaire, and (d) administrative resident data. Generalized estimating equations (GEEs) were applied to examine AOC's relationships with selected antecedents and care personnel outcomes. RESULTS: Data were collected from 5,323 care personnel in 163 nursing homes (return rate: 76%). On a scale from 1 to 5, the mean level of AOC was 3.86 (standard deviation = 0.81). Variations in AOC regarding care personnel characteristics (age, education, and experience in nursing home) and organizational characteristics (size, profit status) were statistically significant with minimal effect sizes. The main factors positively related to AOC were leadership, job satisfaction, quality of care, and collaboration with the nursing home director. Care personnel outcomes significantly related to higher AOC were reduced intention to leave, health complaints, presenteeism, and absenteeism. IMPLICATIONS: As leadership is a crucial factor of AOC, its development might improve care personnel outcomes such as intention to leave or absenteeism.


Assuntos
Atitude do Pessoal de Saúde , Pessoal de Saúde , Casas de Saúde , Apego ao Objeto , Lealdade ao Trabalho , Absenteísmo , Adulto , Comportamento Cooperativo , Estudos Transversais , Feminino , Humanos , Satisfação no Emprego , Liderança , Masculino , Pessoa de Meia-Idade , Recursos Humanos de Enfermagem , Presenteísmo , Autonomia Profissional , Qualidade da Assistência à Saúde , Inquéritos e Questionários , Suíça
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