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1.
Anticancer Res ; 41(9): 4295-4304, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34475049

RESUMO

BACKGROUND/AIM: Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults. The aim of this study was to elucidate the molecular pathogenesis of sporadic RCC in Taiwan. MATERIALS AND METHODS: Fifteen patients with RCC were screened for mutations in the von Hippel-Lindau (VHL) gene by PCR and Sanger sequencing. The methylation status of promoters of 24 tumor suppressor genes by methylation sensitive multiplex ligation-dependent probe amplification analysis was also determined. RESULTS: Inactivation of the VHL gene was observed in 5 cases: three missense somatic mutations, one promoter methylation, and one small deletion. In RCCs, methylation was most frequently observed in APC (100%), CDKN2B (92.9%), CASP8, MLH1_167, and KLLN (85.7.4%), but not in FHIT, MLH1_463, DAPK1, or HIC1 (0%). CONCLUSION: In addition to VHL inactivation, promoter methylation of APC may be a universal pathognomonic event in the tumorigenesis of RCC and a candidate diagnostic and therapeutic biomarker.


Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Carcinoma de Células Renais/diagnóstico , Metilação de DNA , Neoplasias Renais/diagnóstico , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Biomarcadores Tumorais/genética , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Detecção Precoce de Câncer , Epigênese Genética , Feminino , Humanos , Neoplasias Renais/genética , Neoplasias Renais/patologia , Masculino , Mutação de Sentido Incorreto , Estadiamento de Neoplasias , Regiões Promotoras Genéticas , Análise de Sequência de DNA , Deleção de Sequência
2.
Int J Mol Sci ; 22(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34360843

RESUMO

Wolfram syndrome is a rare autosomal recessive disorder characterized by optic atrophy and diabetes mellitus. Wolfram syndrome type 1 (WFS1) is caused by bi-allelic pathogenic variations in the wolframin gene. We described the first case of WFS1 due to a maternal inherited mutation with uniparental mero-isodisomy of chromosome 4. Diabetes mellitus was diagnosed at 11 years of age, with negative anti-beta cells antibodies. Blood glucose control was optimal with low insulin requirement. No pathogenic variations in the most frequent gene causative of maturity-onset diabetes of the young subtypes were detected. At 17.8 years old, a rapid reduction in visual acuity occurred. Genetic testing revealed the novel homozygous variant c.1369A>G; p.Arg457Gly in the exon 8 of wolframin gene. It was detected in a heterozygous state only in the mother while the father showed a wild type sequence. In silico disease causing predictions performed by Polyphen2 classified it as "likely damaging", while Mutation Tester and Sift suggested it was "polymorphism" and "tolerated", respectively. High resolution SNP-array analysis was suggestive of segmental uniparental disomy on chromosome 4. In conclusion, to the best of our knowledge, we describe the first patient with partial uniparental mero-isodisomy of chromosome 4 carrying a novel mutation in the wolframin gene. The clinical phenotype observed in the patient and the analysis performed suggest that the genetic variant detected is pathogenetic.


Assuntos
Cromossomos Humanos Par 4 , Proteínas de Membrana/genética , Mutação de Sentido Incorreto , Dissomia Uniparental , Síndrome de Wolfram/genética , Feminino , Humanos , Adulto Jovem
3.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360957

RESUMO

In recent years, the "non-autonomous motor neuron death" hypothesis has become more consolidated behind amyotrophic lateral sclerosis (ALS). It postulates that cells other than motor neurons participate in the pathology. In fact, the involvement of the autonomic nervous system is fundamental since patients die of sudden death when they become unable to compensate for cardiorespiratory arrest. Mitochondria are thought to play a fundamental role in the physiopathology of ALS, as they are compromised in multiple ALS models in different cell types, and it also occurs in other neurodegenerative diseases. Our study aimed to uncover mitochondrial alterations in the sympathoadrenal system of a mouse model of ALS, from a structural, bioenergetic and functional perspective during disease instauration. We studied the adrenal chromaffin cell from mutant SOD1G93A mouse at pre-symptomatic and symptomatic stages. The mitochondrial accumulation of the mutated SOD1G93A protein and the down-regulation of optic atrophy protein-1 (OPA1) provoke mitochondrial ultrastructure alterations prior to the onset of clinical symptoms. These changes affect mitochondrial fusion dynamics, triggering mitochondrial maturation impairment and cristae swelling, with increased size of cristae junctions. The functional consequences are a loss of mitochondrial membrane potential and changes in the bioenergetics profile, with reduced maximal respiration and spare respiratory capacity of mitochondria, as well as enhanced production of reactive oxygen species. This study identifies mitochondrial dynamics regulator OPA1 as an interesting therapeutic target in ALS. Additionally, our findings in the adrenal medulla gland from presymptomatic stages highlight the relevance of sympathetic impairment in this disease. Specifically, we show new SOD1G93A toxicity pathways affecting cellular energy metabolism in non-motor neurons, which offer a possible link between cell specific metabolic phenotype and the progression of ALS.


Assuntos
Esclerose Amiotrófica Lateral/genética , GTP Fosfo-Hidrolases/metabolismo , Mitocôndrias/metabolismo , Superóxido Dismutase-1/genética , Glândulas Suprarrenais/citologia , Esclerose Amiotrófica Lateral/metabolismo , Animais , Células Cultivadas , Células Cromafins/metabolismo , Regulação para Baixo , GTP Fosfo-Hidrolases/genética , Potencial da Membrana Mitocondrial , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/ultraestrutura , Mutação de Sentido Incorreto , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase-1/metabolismo
4.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(8): 787-790, 2021 Aug 10.
Artigo em Chinês | MEDLINE | ID: mdl-34365626

RESUMO

OBJECTIVE: To explore the genetic basis for a sib pair featuring 17beta-hydroxysteroid dehydrogenase type 3 deficiency. METHODS: Genomic DNA was extracted from the proband, her sister, and their parents, and was subjected to sequencing analysis with a gene panel for sexual development. Suspected variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: Both the proband and her sister were found to harbor novel compound heterozygous missense variants of the HSD17B3 gene, namely c.839T>C (p.Leu280Pro) and c.239G>T (p.Arg80Leu), which were derived respectively from their mother and father. The variants were unreported previously and predicted to be deleterious by PolyPhen2, MutationTaster and other online software. Based on the American College of Medical Genetics and Genomics standards and guidelines, both c.839T>C(p.Leu280Pro) and c.239G>T (p.Arg80Leu) were predicted to be likely pathogenic (PM2+PP1+PP2+PP3+PP4, PM2+PM5+PP1+PP2+PP3+PP4). CONCLUSION: The compound heterogeneous variants of the HSD17B3 gene probably underlay the disease in this sib pair. 17beta-hydroxysteroid dehydrogenase type 3 deficiency may lack specific clinical features and laboratory index, genetic testing can facilitate a definitive diagnosis.


Assuntos
Testes Genéticos , Genômica , 17-Hidroxiesteroide Desidrogenases/genética , Feminino , Humanos , Mutação , Mutação de Sentido Incorreto
5.
Science ; 373(6557): 918-922, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34413236

RESUMO

Zoonotic avian influenza A virus (IAV) infections are rare. Sustained transmission of these IAVs between humans has not been observed, suggesting a role for host genes. We used whole-genome sequencing to compare avian IAV H7N9 patients with healthy controls and observed a strong association between H7N9 infection and rare, heterozygous single-nucleotide variants in the MX1 gene. MX1 codes for myxovirus resistance protein A (MxA), an interferon-induced antiviral guanosine triphosphatase known to control IAV infections in transgenic mice. Most of the MxA variants identified lost the ability to inhibit avian IAVs, including H7N9, in transfected human cell lines. Nearly all of the inactive MxA variants exerted a dominant-negative effect on the antiviral function of wild-type MxA, suggesting an MxA null phenotype in heterozygous carriers. Our study provides genetic evidence for a crucial role of the MX1-based antiviral defense in controlling zoonotic IAV infections in humans.


Assuntos
Subtipo H7N9 do Vírus da Influenza A , Influenza Humana/genética , Influenza Humana/virologia , Proteínas de Resistência a Myxovirus/genética , Doenças dos Trabalhadores Agrícolas/genética , Doenças dos Trabalhadores Agrícolas/virologia , Animais , Linhagem Celular , Predisposição Genética para Doença , Variação Genética , Heterozigoto , Humanos , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Vírus da Influenza A/fisiologia , Mutação de Sentido Incorreto , Proteínas de Resistência a Myxovirus/química , Proteínas de Resistência a Myxovirus/metabolismo , Aves Domésticas , Zoonoses Virais , Sequenciamento Completo do Genoma
6.
Int J Mol Sci ; 22(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34360815

RESUMO

An enzyme of the mammalian amino-sugar metabolism pathway, N-acetylglucosamine kinase (NAGK), that synthesizes N-acetylglucosamine (GlcNAc)-6-phosphate, is reported to promote dynein functions during mitosis, axonal and dendritic growth, cell migration, and selective autophagy, which all are unrelated to its enzyme activity. As non-enzymatic structural functions can be altered by genetic variation, we made an effort in this study aimed at deciphering the pathological effect of nonsynonymous single-nucleotide polymorphisms (nsSNPs) in NAGK gene. An integrated computational approach, including molecular dynamics (MD) simulation and protein-protein docking simulation, was used to identify the damaging nsSNPs and their detailed structural and functional consequences. The analysis revealed the four most damaging variants (G11R, G32R, G120E, and A156D), which are highly conserved and functional, positioned in both small (G11R and G32R) and large (G120E and A156D) domains of NAGK. G11R is located in the ATP binding region, while variants present in the large domain (G120E and A156D) were found to induce substantial alterations in the structural organizations of both domains, including the ATP and substrate binding sites. Furthermore, all variants were found to reduce binding energy between NAGK and dynein subunit DYNLRB1, as revealed by protein-protein docking and MM-GBSA binding energy calculation supporting their deleteriousness on non-canonical function. We hope these findings will direct future studies to gain more insight into the role of these variants in the loss of NAGK function and their role in neurodevelopmental disorders.


Assuntos
Fosfotransferases (Aceptor do Grupo Álcool) , Sítios de Ligação , Dineínas do Citoplasma/metabolismo , Humanos , Mutação de Sentido Incorreto , Fosfotransferases (Aceptor do Grupo Álcool)/química , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/fisiologia , Polimorfismo de Nucleotídeo Único , Ligação Proteica , Domínios Proteicos , Elementos Estruturais de Proteínas , Relação Estrutura-Atividade
7.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360942

RESUMO

The exact mechanism underlying selective dopaminergic neurodegeneration is not completely understood. The complex interplay among toxic alpha-synuclein aggregates, oxidative stress, altered intracellular Ca2+-homeostasis, mitochondrial dysfunction and disruption of mitochondrial integrity is considered among the pathogenic mechanisms leading to dopaminergic neuronal loss. We herein investigated the molecular mechanisms leading to mitochondrial dysfunction and its relationship with activation of the neuroinflammatory process occurring in Parkinson's disease. To address these issues, experiments were performed in vitro and in vivo in mice carrying the human mutation of α-synuclein A53T under the prion murine promoter. In these models, the expression and activity of NCX isoforms, a family of important transporters regulating ionic homeostasis in mammalian cells working in a bidirectional way, were evaluated in neurons and glial cells. Mitochondrial function was monitored with confocal microscopy and fluorescent dyes to measure mitochondrial calcium content and mitochondrial membrane potential. Parallel experiments were performed in 4 and 16-month-old A53T-α-synuclein Tg mice to correlate the functional data obtained in vitro with mitochondrial dysfunction and neuroinflammation through biochemical analysis. The results obtained demonstrated: 1. in A53T mice mitochondrial dysfunction occurs early in midbrain and later in striatum; 2. mitochondrial dysfunction occurring in the midbrain is mediated by the impairment of NCX3 protein expression in neurons and astrocytes; 3. mitochondrial dysfunction occurring early in midbrain triggers neuroinflammation later into the striatum, thus contributing to PD progression during mice aging.


Assuntos
Mesencéfalo/metabolismo , Mitocôndrias/metabolismo , Doença de Parkinson/metabolismo , Trocador de Sódio e Cálcio/metabolismo , alfa-Sinucleína/genética , Animais , Astrócitos/metabolismo , Cálcio/metabolismo , Células Cultivadas , Neurônios Dopaminérgicos/metabolismo , Mesencéfalo/citologia , Camundongos , Camundongos Endogâmicos C57BL , Mutação de Sentido Incorreto , Doença de Parkinson/genética , Trocador de Sódio e Cálcio/genética , alfa-Sinucleína/metabolismo
8.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34360596

RESUMO

Twenty-one human genes encode connexins, a family of homologous proteins making gap junction (GJ) channels, which mediate direct intercellular communication to synchronize tissue/organ activities. Genetic variants in more than half of the connexin genes are associated with dozens of different Mendelian inherited diseases. With rapid advances in DNA sequencing technology, more variants are being identified not only in families and individuals with diseases but also in people in the general population without any apparent linkage to Mendelian inherited diseases. Nevertheless, it remains challenging to classify the pathogenicity of a newly identified connexin variant. Here, we analyzed the disease- and Genome Aggregation Database (gnomAD, as a proxy of the general population)-linked variants in the coding region of the four disease-linked α connexin genes. We found that the most abundant and position-sensitive missense variants showed distinct domain distribution preference between disease- and gnomAD-linked variants. Plotting missense variants on topological and structural models revealed that disease-linked missense variants are highly enriched on the structurally stable/resolved domains, especially the pore-lining domains, while the gnomAD-linked missense variants are highly enriched in the structurally unstable/unresolved domains, especially the carboxyl terminus. In addition, disease-linked variants tend to be on highly conserved residues and those positions show evolutionary co-variation, while the gnomAD-linked missense variants are likely on less conserved residue positions and on positions without co-variation. Collectively, the revealed distribution patterns of disease- and gnomAD-linked missense variants further our understanding of the GJ structure-biological function relationship, which is valuable for classifying the pathogenicity of newly identified connexin variants.


Assuntos
Conexinas/genética , Bases de Dados Genéticas , Junções Comunicantes/genética , Doenças Genéticas Inatas/patologia , Genética Populacional , Mutação de Sentido Incorreto , Sequência de Aminoácidos , Doenças Genéticas Inatas/genética , Humanos , Domínios Proteicos , Homologia de Sequência
9.
Front Immunol ; 12: 719115, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34367187

RESUMO

Introduction: Loss-of-function TLR7 variants have been recently reported in a small number of males to underlie strong predisposition to severe COVID-19. We aimed to determine the presence of these rare variants in young men with severe COVID-19. Methods: We prospectively studied males between 18 and 50 years-old without predisposing comorbidities that required at least high-flow nasal oxygen to treat COVID-19. The coding region of TLR7 was sequenced to assess the presence of potentially deleterious variants. Results: TLR7 missense variants were identified in two out of 14 patients (14.3%). Overall, the median age was 38 (IQR 30-45) years. Both variants were not previously reported in population control databases and were predicted to be damaging by in silico predictors. In a 30-year-old patient a maternally inherited variant [c.644A>G; p.(Asn215Ser)] was identified, co-segregating in his 27-year-old brother who also contracted severe COVID-19. A second variant [c.2797T>C; p.(Trp933Arg)] was found in a 28-year-old patient, co-segregating in his 24-year-old brother who developed mild COVID-19. Functional testing of this variant revealed decreased type I and II interferon responses in peripheral mononuclear blood cells upon stimulation with the TLR7 agonist imiquimod, confirming a loss-of-function effect. Conclusions: This study supports a rationale for the genetic screening for TLR7 variants in young men with severe COVID-19 in the absence of other relevant risk factors. A diagnosis of TLR7 deficiency could not only inform on treatment options for the patient, but also enables pre-symptomatic testing of at-risk male relatives with the possibility of instituting early preventive and therapeutic interventions.


Assuntos
COVID-19/genética , Mutação de Sentido Incorreto , SARS-CoV-2 , Receptor 7 Toll-Like/genética , Adulto , Substituição de Aminoácidos , COVID-19/imunologia , COVID-19/patologia , Testes Genéticos , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Índice de Gravidade de Doença , Receptor 7 Toll-Like/imunologia
10.
Cell Mol Life Sci ; 78(16): 6017-6031, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34245311

RESUMO

A precondition for efficient proinsulin export from the endoplasmic reticulum (ER) is that proinsulin meets ER quality control folding requirements, including formation of the Cys(B19)-Cys(A20) "interchain" disulfide bond, facilitating formation of the Cys(B7)-Cys(A7) bridge. The third proinsulin disulfide, Cys(A6)-Cys(A11), is not required for anterograde trafficking, i.e., a "lose-A6/A11" mutant [Cys(A6), Cys(A11) both converted to Ser] is well secreted. Nevertheless, an unpaired Cys(A11) can participate in disulfide mispairings, causing ER retention of proinsulin. Among the many missense mutations causing the syndrome of Mutant INS gene-induced Diabetes of Youth (MIDY), all seem to exhibit perturbed proinsulin disulfide bond formation. Here, we have examined a series of seven MIDY mutants [including G(B8)V, Y(B26)C, L(A16)P, H(B5)D, V(B18)A, R(Cpep + 2)C, E(A4)K], six of which are essentially completely blocked in export from the ER in pancreatic ß-cells. Three of these mutants, however, must disrupt the Cys(A6)-Cys(A11) pairing to expose a critical unpaired cysteine thiol perturbation of proinsulin folding and ER export, because when introduced into the proinsulin lose-A6/A11 background, these mutants exhibit native-like disulfide bonding and improved trafficking. This maneuver also ameliorates dominant-negative blockade of export of co-expressed wild-type proinsulin. A growing molecular understanding of proinsulin misfolding may permit allele-specific pharmacological targeting for some MIDY mutants.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Proinsulina/metabolismo , Adolescente , Células Cultivadas , Cisteína/genética , Cisteína/metabolismo , Diabetes Mellitus Tipo 2/genética , Dissulfetos/metabolismo , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Humanos , Insulina/genética , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Mutação de Sentido Incorreto/genética , Proinsulina/genética , Dobramento de Proteína
11.
Am J Hum Genet ; 108(7): 1283-1300, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34214447

RESUMO

Most rare clinical missense variants cannot currently be classified as pathogenic or benign. Deficiency in human 5,10-methylenetetrahydrofolate reductase (MTHFR), the most common inherited disorder of folate metabolism, is caused primarily by rare missense variants. Further complicating variant interpretation, variant impacts often depend on environment. An important example of this phenomenon is the MTHFR variant p.Ala222Val (c.665C>T), which is carried by half of all humans and has a phenotypic impact that depends on dietary folate. Here we describe the results of 98,336 variant functional-impact assays, covering nearly all possible MTHFR amino acid substitutions in four folinate environments, each in the presence and absence of p.Ala222Val. The resulting atlas of MTHFR variant effects reveals many complex dependencies on both folinate and p.Ala222Val. MTHFR atlas scores can distinguish pathogenic from benign variants and, among individuals with severe MTHFR deficiency, correlate with age of disease onset. Providing a powerful tool for understanding structure-function relationships, the atlas suggests a role for a disordered loop in retaining cofactor at the active site and identifies variants that enable escape of inhibition by S-adenosylmethionine. Thus, a model based on eight MTHFR variant effect maps illustrates how shifting landscapes of environment- and genetic-background-dependent missense variation can inform our clinical, structural, and functional understanding of MTHFR deficiency.


Assuntos
Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Mutação de Sentido Incorreto , Substituição de Aminoácidos , Análise Mutacional de DNA , Diploide , Biblioteca Gênica , Genótipo , Humanos , Metilenotetra-Hidrofolato Redutase (NADPH2)/deficiência , Metilenotetra-Hidrofolato Redutase (NADPH2)/fisiologia , Saccharomyces cerevisiae/genética
12.
Int J Mol Sci ; 22(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34210092

RESUMO

Brain-derived neurotrophic factor (BDNF) is a pleiotropic neuronal growth and survival factor that is indispensable in the brain, as well as in multiple other tissues and organs, including the cardiovascular system. In approximately 30% of the general population, BDNF harbors a nonsynonymous single nucleotide polymorphism that may be associated with cardiometabolic disorders, coronary artery disease, and Duchenne muscular dystrophy cardiomyopathy. We recently showed that transgenic mice with the human BDNF rs6265 polymorphism (Val66Met) exhibit altered cardiac function, and that cardiomyocytes isolated from these mice are also less contractile. To identify the underlying mechanisms involved, we compared cardiac function by echocardiography and performed deep sequencing of RNA extracted from whole hearts of all three genotypes (Val/Val, Val/Met, and Met/Met) of both male and female Val66Met mice. We found female-specific cardiac alterations in both heterozygous and homozygous carriers, including increased systolic (26.8%, p = 0.047) and diastolic diameters (14.9%, p = 0.022), increased systolic (57.9%, p = 0.039) and diastolic volumes (32.7%, p = 0.026), and increased stroke volume (25.9%, p = 0.033), with preserved ejection fraction and fractional shortening. Both males and females exhibited lower heart rates, but this change was more pronounced in female mice than in males. Consistent with phenotypic observations, the gene encoding SERCA2 (Atp2a2) was reduced in homozygous Met/Met mice but more profoundly in females compared to males. Enriched functions in females with the Met allele included cardiac hypertrophy in response to stress, with down-regulation of the gene encoding titin (Tcap) and upregulation of BNP (Nppb), in line with altered cardiac functional parameters. Homozygous male mice on the other hand exhibited an inflammatory profile characterized by interferon-γ (IFN-γ)-mediated Th1 immune responses. These results provide evidence for sex-based differences in how the BDNF polymorphism modifies cardiac physiology, including female-specific alterations of cardiac-specific transcripts and male-specific activation of inflammatory targets.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Substituição de Aminoácidos , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Feminino , Expressão Gênica , Masculino , Metionina/genética , Camundongos , Camundongos Transgênicos , Mutação de Sentido Incorreto , Polimorfismo de Nucleotídeo Único , Caracteres Sexuais , Valina/genética , Função Ventricular/genética , Função Ventricular/fisiologia
13.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207526

RESUMO

Mutations in the PSEN1 gene are the most common cause of autosomal dominant Alzheimer's disease, and are characterized by a high phenotype variability. This study describes a five-generation family, with a prevalent late-onset of the disease and a high frequency of depression, in which a new missense mutation (c.789T > G, p.Cys263Trp) in exon 8 of the PSEN1 gene was found. Only the proband presented an early onset at the age of 45 with attention deficit, followed by spatial disorientation, psychiatric symptoms and parkinsonian signs. The other two cases had a late onset of the disease and a typical presentation with memory loss. Both were characterized by a high level of anxiety and depression. The disease course was different with signs of Lewy body dementia for the proband's mother, and pyramidal involvement and a shorter disease duration for the proband's maternal aunt. The other eight cases with late-onset dementia and three cases with a long history of depression have been reported in the family pedigree, underlying the high phenotype variability of PSEN1 mutations.


Assuntos
Doença de Alzheimer/genética , Família , Mutação de Sentido Incorreto , Linhagem , Presenilina-1/genética , Idade de Início , Substituição de Aminoácidos , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade
14.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207612

RESUMO

The present limitations in the pathogenicity prediction of BRCA1 and BRCA2 (BRCA1/2) missense variants constitute an important problem with negative consequences for the diagnosis of hereditary breast and ovarian cancer. However, it has been proposed that the use of endophenotype predictions, i.e., computational estimates of the outcomes of functional assays, can be a good option to address this bottleneck. The application of this idea to the BRCA1/2 variants in the CAGI 5-ENIGMA international challenge has shown promising results. Here, we developed this approach, exploring the predictive performances of the regression models applied to the BRCA1/2 variants for which the values of the homology-directed DNA repair and saturation genome editing assays are available. Our results first showed that we can generate endophenotype estimates using a few molecular-level properties. Second, we show that the accuracy of these estimates is enough to obtain pathogenicity predictions comparable to those of many standard tools. Third, endophenotype-based predictions are complementary to, but do not outperform, those of a Random Forest model trained using variant pathogenicity annotations instead of endophenotype values. In summary, our results confirmed the usefulness of the endophenotype approach for the pathogenicity prediction of the BRCA1/2 missense variants, suggesting different options for future improvements.


Assuntos
Proteína BRCA1 , Proteína BRCA2 , Simulação por Computador , Modelos Biológicos , Mutação de Sentido Incorreto , Neoplasias Ovarianas , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Feminino , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo
15.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(7): 620-625, 2021 Jul 10.
Artigo em Chinês | MEDLINE | ID: mdl-34247363

RESUMO

OBJECTIVE: To analyze the pathogenic variants of the KIF1A gene and its corresponding protein structure in an autism spectrum disorder (ASD) family trio carrying harmful missense variants in the KIF1A gene. METHODS: The peripheral blood DNA of the patient and his parents was extracted and sequenced using whole exome sequencing (WES) technology and verified by Sanger sequencing. Bioinformatics software SIFT, PolyPhen-2, Mutation Taster, and CADD software were used to analyze the harmfulness and conservation of variants. The Human Brain Transcriptome (HBT) database was used to analyze the expression of the KIF1A gene in the brain. PredictProtein and SWISS-MODEL were further used to predict the secondary structure and tertiary structure of KIF1A wild-type protein and variant protein. PyMOL V2.4 was utilized to investigate the change of hydrogen bond connection after protein variant. RESULTS: The WES sequencing revealed a missense variant c.664A>C (p.Asn222His) in the child's KIF1A gene, and this variant was a de novo variant. The harmfulness prediction results suggest that this variant is harmful. By analyzing expression level of KIF1A gene in the brain. It is found that KIF1A gene widely expressed in various brain regions during embryonic development. By analyzing the variant protein structure, the missense variant of KIF1A will cause many changes in the secondary structure of protein, such as alpha-helix, beta-strand, and protein binding domain. The connection of hydrogen bond and spatial structure will also change, thereby changing the original biological function. CONCLUSION: The KIF1A gene may be a risk gene for ASD.


Assuntos
Transtorno do Espectro Autista , Transtorno do Espectro Autista/genética , Criança , Feminino , Humanos , Cinesina/genética , Mutação , Mutação de Sentido Incorreto , Gravidez , Domínios Proteicos , Sequenciamento Completo do Exoma
16.
Eur J Med Genet ; 64(9): 104285, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34229114

RESUMO

Recently, an autosomal recessive disorder including the triad of microcephaly, infantile epileptic encephalopathy, and permanent neonatal diabetes syndrome (MEDS, OMIM#614231) has emerged as a new distinguishing syndrome. Eight cases of whom seven from Arab countries, have been reported in association with biallelic variants in the IER3IP1 gene (Immediate early response-3 interacting protein-1). Here, we describe a Tunisian boy who presented with permanent neonatal diabetes, microcephaly, generalized seizures and hypovirilized external genitalia consisting of a small genitalia and unilateral cryptorchidism. Chromosomal analysis indicated a 46, XY karyotype in all metaphases. Exome sequencing identified a homozygous missense variant (c.62 T > G; p. Val21Gly) in the IER3IP1 gene, that is predicted to alter the protein structure within the hydrophobic/transmembrane. This variant was previously reported in two cases associated with MEDS. This is the first reported case of MEDS in Tunisia. Our report focuses on the IER3IP1 related phenotypic spectrum and assumes abnormal genitalia as part of the syndrome. Consequently, we recommend to perform hormonal testing on this topic to understand the effect of the IER3IP1 variant on the male genital pathway.


Assuntos
Proteínas de Transporte/genética , Criptorquidismo/patologia , Diabetes Mellitus/patologia , Epilepsia/patologia , Doenças do Recém-Nascido/patologia , Proteínas de Membrana/genética , Transtornos Psicomotores/patologia , Proteínas de Transporte/química , Criptorquidismo/genética , Diabetes Mellitus/genética , Epilepsia/genética , Humanos , Recém-Nascido , Doenças do Recém-Nascido/genética , Cariótipo , Masculino , Proteínas de Membrana/química , Mutação de Sentido Incorreto , Domínios Proteicos , Transtornos Psicomotores/genética , Síndrome
17.
PLoS Pathog ; 17(7): e1009715, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34270613

RESUMO

SARS-CoV and SARS-CoV-2 encode spike proteins that bind human ACE2 on the cell surface to enter target cells during infection. A small fraction of humans encode variants of ACE2, thus altering the biochemical properties at the protein interaction interface. These and other ACE2 coding mutants can reveal how the spike proteins of each virus may differentially engage the ACE2 protein surface during infection. We created an engineered HEK 293T cell line for facile stable transgenic modification, and expressed the major human ACE2 allele or 28 of its missense mutants, 24 of which are possible through single nucleotide changes from the human reference sequence. Infection with SARS-CoV or SARS-CoV-2 spike pseudotyped lentiviruses revealed that high ACE2 cell-surface expression could mask the effects of impaired binding during infection. Drastically reducing ACE2 cell surface expression revealed a range of infection efficiencies across the panel of mutants. Our infection results revealed a non-linear relationship between soluble SARS-CoV-2 RBD binding to ACE2 and pseudovirus infection, supporting a major role for binding avidity during entry. While ACE2 mutants D355N, R357A, and R357T abrogated entry by both SARS-CoV and SARS-CoV-2 spike proteins, the Y41A mutant inhibited SARS-CoV entry much more than SARS-CoV-2, suggesting differential utilization of the ACE2 side-chains within the largely overlapping interaction surfaces utilized by the two CoV spike proteins. These effects correlated well with cytopathic effects observed during SARS-CoV-2 replication in ACE2-mutant cells. The panel of ACE2 mutants also revealed altered ACE2 surface dependencies by the N501Y spike variant, including a near-complete utilization of the K353D ACE2 variant, despite decreased infection mediated by the parental SARS-CoV-2 spike. Our results clarify the relationship between ACE2 abundance, binding, and infection, for various SARS-like coronavirus spike proteins and their mutants, and inform our understanding for how changes to ACE2 sequence may correspond with different susceptibilities to infection.


Assuntos
Enzima de Conversão de Angiotensina 2/genética , COVID-19/etiologia , Vírus da SARS/fisiologia , SARS-CoV-2/fisiologia , Síndrome Respiratória Aguda Grave/etiologia , Glicoproteína da Espícula de Coronavírus/fisiologia , Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/genética , COVID-19/virologia , Células HEK293 , Humanos , Mutação de Sentido Incorreto , Síndrome Respiratória Aguda Grave/genética , Síndrome Respiratória Aguda Grave/virologia
18.
Int J Mol Sci ; 22(14)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34299011

RESUMO

Osteoporosis is the most common metabolic bone disorder and nitrogen-containing bisphosphonates (BP) are a first line treatment for it. Yet, atypical femoral fractures (AFF), a rare adverse effect, may appear after prolonged BP administration. Given the low incidence of AFF, an underlying genetic cause that increases the susceptibility to these fractures is suspected. Previous studies uncovered rare CYP1A1 mutations in osteoporosis patients who suffered AFF after long-term BP treatment. CYP1A1 is involved in drug metabolism and steroid catabolism, making it an interesting candidate. However, a functional validation for the AFF-associated CYP1A1 mutations was lacking. Here we tested the enzymatic activity of four such CYP1A1 variants, by transfecting them into Saos-2 cells. We also tested the effect of commonly used BPs on the enzymatic activity of the CYP1A1 forms. We demonstrated that the p.Arg98Trp and p.Arg136His CYP1A1 variants have a significant negative effect on enzymatic activity. Moreover, all the BP treatments decreased CYP1A1 activity, although no specific interaction with CYP1A1 variants was found. Our results provide functional support to the hypothesis that an additive effect between CYP1A1 heterozygous mutations p.Arg98Trp and p.Arg136His, other rare mutations and long-term BP exposure might generate susceptibility to AFF.


Assuntos
Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Fraturas do Fêmur/genética , Fraturas do Fêmur/metabolismo , Sequência de Aminoácidos , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Citocromo P-450 CYP1A1/química , Difosfonatos/uso terapêutico , Fraturas do Fêmur/enzimologia , Humanos , Incidência , Mutagênese Sítio-Dirigida , Mutação de Sentido Incorreto , Filogenia , Alinhamento de Sequência
19.
Biochemistry (Mosc) ; 86(6): 627-640, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34225587

RESUMO

DJ-1, also known as Parkinson's disease protein 7, is a multifunctional protein ubiquitously expressed in cells and tissues. Interacting with proteins of various intracellular compartments, DJ-1 plays an important role in maintaining different cellular functions. Mutant DJ-1 forms containing amino acid substitutions (especially L166P), typical of Parkinson's disease, are characterized by impaired dimerization, stability, and folding. DJ-1 exhibits several types of catalytic activity; however, in the enzyme classification it exists as protein deglycase (EC 3.5.1.124). Apparently, in different cell compartments DJ-1 exhibits catalytic and non-catalytic functions, and their ratio still remains unknown. Oxidative stress promotes dissociation of cytoplasmic DJ-1 dimers into monomers, which are translocated to the nucleus, where this protein acts as a coactivator of various signaling pathways, preventing cell death. In mitochondria, DJ-1 is found in the synthasome, where it interacts with the ß ATP synthase subunit. Downregulation of the DJ-1 gene under conditions of experimental PD increases sensitivity of the cells to neurotoxins, and introduction of the recombinant DJ-1 protein attenuates manifestation of this pathology. The thirteen-membered fragment of the DJ-1 amino acid sequence attached to the heptapeptide of the TAT protein penetrating into the cells exhibited neuroprotective properties in various PD models both in cell cultures and after administration to animals. Low molecular weight DJ-1 ligands also demonstrate therapeutic potential, providing neuroprotective effects seen during their incubation with cells and administration to animals.


Assuntos
Modelos Animais de Doenças , Mutação de Sentido Incorreto , Doença de Parkinson/metabolismo , Proteína Desglicase DJ-1/metabolismo , Animais , Humanos , Modelos Biológicos , Doença de Parkinson/etiologia , Doença de Parkinson/fisiopatologia , Conformação Proteica , Proteína Desglicase DJ-1/genética , Transdução de Sinais
20.
Int J Mol Sci ; 22(12)2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34198491

RESUMO

Rare germline pathogenic TP53 missense variants often predispose to a wide spectrum of tumors characterized by Li-Fraumeni syndrome (LFS) but a subset of variants is also seen in families with exclusively hereditary breast cancer (HBC) outcomes. We have developed a logistic regression model with the aim of predicting LFS and HBC outcomes, based on the predicted effects of individual TP53 variants on aspects of protein conformation. A total of 48 missense variants either unique for LFS (n = 24) or exclusively reported in HBC (n = 24) were included. LFS-variants were over-represented in residues tending to be buried in the core of the tertiary structure of TP53 (p = 0.0014). The favored logistic regression model describes disease outcome in terms of explanatory variables related to the surface or buried status of residues as well as their propensity to contribute to protein compactness or protein-protein interactions. Reduced, internally validated models discriminated well between LFS and HBC (C-statistic = 0.78-0.84; equivalent to the area under the ROC (receiver operating characteristic) curve), had a low risk for over-fitting and were well calibrated in relation to the known outcome risk. In conclusion, this study presents a phenotypic prediction model of LFS and HBC risk for germline TP53 missense variants, in an attempt to provide a complementary tool for future decision making and clinical handling.


Assuntos
Neoplasias da Mama/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Síndrome de Li-Fraumeni/genética , Mutação de Sentido Incorreto/genética , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/genética , Sequência de Aminoácidos , Feminino , Mutação em Linhagem Germinativa/genética , Humanos , Modelos Logísticos , Análise Multivariada , Fenótipo , Conformação Proteica
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