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1.
Nat Genet ; 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31578528

RESUMO

Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.

2.
Nat Commun ; 10(1): 4130, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511532

RESUMO

Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria.

3.
Nat Genet ; 51(6): 957-972, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31152163

RESUMO

Chronic kidney disease (CKD) is responsible for a public health burden with multi-systemic complications. Through trans-ancestry meta-analysis of genome-wide association studies of estimated glomerular filtration rate (eGFR) and independent replication (n = 1,046,070), we identified 264 associated loci (166 new). Of these, 147 were likely to be relevant for kidney function on the basis of associations with the alternative kidney function marker blood urea nitrogen (n = 416,178). Pathway and enrichment analyses, including mouse models with renal phenotypes, support the kidney as the main target organ. A genetic risk score for lower eGFR was associated with clinically diagnosed CKD in 452,264 independent individuals. Colocalization analyses of associations with eGFR among 783,978 European-ancestry individuals and gene expression across 46 human tissues, including tubulo-interstitial and glomerular kidney compartments, identified 17 genes differentially expressed in kidney. Fine-mapping highlighted missense driver variants in 11 genes and kidney-specific regulatory variants. These results provide a comprehensive priority list of molecular targets for translational research.


Assuntos
Estudos de Associação Genética/métodos , Predisposição Genética para Doença , Locos de Características Quantitativas , Característica Quantitativa Herdável , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/fisiopatologia , Mapeamento Cromossômico , Grupo com Ancestrais do Continente Europeu , Estudo de Associação Genômica Ampla , Taxa de Filtração Glomerular , Humanos , Padrões de Herança , Testes de Função Renal , Fenótipo , Polimorfismo de Nucleotídeo Único , Insuficiência Renal Crônica/urina , Uromodulina/urina
5.
Eur J Hum Genet ; 26(8): 1167-1179, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29725052

RESUMO

Age-related hearing loss (ARHL) is the most common sensory disorder in the elderly. Although not directly life threatening, it contributes to loss of autonomy and is associated with anxiety, depression and cognitive decline. To search for genetic risk factors underlying ARHL, a large whole-genome sequencing (WGS) approach has been carried out in a cohort of 212 cases and controls, both older than 50 years to select genes characterized by a burden of variants specific to cases or controls. Accordingly, the total variation load per gene was compared and two groups were detected: 375 genes more variable in cases and 371 more variable in controls. In both cases, Gene Ontology analysis showed that the largest enrichment for biological processes (fold > 5, p-value = 0.042) was the "sensory perception of sound", suggesting cumulative genetic effects were involved. Replication confirmed 141 genes, while additional analysis based on natural selection led to a prioritization of 21 genes. The majority of them (20 out of 21) showed positive expression in mouse cochlea cDNA and were associated with two functional pathways. Among them, two genes were previously associated with hearing (CSMD1 and PTRPD) and re-sequenced in a large Italian cohort of ARHL patients (N = 389). Results led to the identification of six coding variants not detected in cases so far, suggesting a possible protective role, which requires investigation. In conclusion, we show that this multistep strategy (WGS, selection, expression, pathway analysis and targeted re-sequencing) can provide major insights into the molecular characterization of complex diseases such as ARHL.

6.
Nat Genet ; 50(5): 652-656, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29662168

RESUMO

Hair color is one of the most recognizable visual traits in European populations and is under strong genetic control. Here we report the results of a genome-wide association study meta-analysis of almost 300,000 participants of European descent. We identified 123 autosomal and one X-chromosome loci significantly associated with hair color; all but 13 are novel. Collectively, single-nucleotide polymorphisms associated with hair color within these loci explain 34.6% of red hair, 24.8% of blond hair, and 26.1% of black hair heritability in the study populations. These results confirm the polygenic nature of complex phenotypes and improve our understanding of melanin pigment metabolism in humans.

8.
Am J Hum Genet ; 100(6): 865-884, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28552196

RESUMO

Deep sequence-based imputation can enhance the discovery power of genome-wide association studies by assessing previously unexplored variation across the common- and low-frequency spectra. We applied a hybrid whole-genome sequencing (WGS) and deep imputation approach to examine the broader allelic architecture of 12 anthropometric traits associated with height, body mass, and fat distribution in up to 267,616 individuals. We report 106 genome-wide significant signals that have not been previously identified, including 9 low-frequency variants pointing to functional candidates. Of the 106 signals, 6 are in genomic regions that have not been implicated with related traits before, 28 are independent signals at previously reported regions, and 72 represent previously reported signals for a different anthropometric trait. 71% of signals reside within genes and fine mapping resolves 23 signals to one or two likely causal variants. We confirm genetic overlap between human monogenic and polygenic anthropometric traits and find signal enrichment in cis expression QTLs in relevant tissues. Our results highlight the potential of WGS strategies to enhance biologically relevant discoveries across the frequency spectrum.


Assuntos
Antropometria , Genoma Humano , Estudo de Associação Genômica Ampla , Locos de Características Quantitativas/genética , Análise de Sequência de DNA/métodos , Estatura/genética , Estudos de Coortes , Metilação de DNA/genética , Bases de Dados Genéticas , Feminino , Variação Genética , Humanos , Lipodistrofia/genética , Masculino , Metanálise como Assunto , Obesidade/genética , Mapeamento Físico do Cromossomo , Caracteres Sexuais , Síndrome , Reino Unido
9.
Sci Rep ; 7: 45040, 2017 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-28452372

RESUMO

HapMap imputed genome-wide association studies (GWAS) have revealed >50 loci at which common variants with minor allele frequency >5% are associated with kidney function. GWAS using more complete reference sets for imputation, such as those from The 1000 Genomes project, promise to identify novel loci that have been missed by previous efforts. To investigate the value of such a more complete variant catalog, we conducted a GWAS meta-analysis of kidney function based on the estimated glomerular filtration rate (eGFR) in 110,517 European ancestry participants using 1000 Genomes imputed data. We identified 10 novel loci with p-value < 5 × 10-8 previously missed by HapMap-based GWAS. Six of these loci (HOXD8, ARL15, PIK3R1, EYA4, ASTN2, and EPB41L3) are tagged by common SNPs unique to the 1000 Genomes reference panel. Using pathway analysis, we identified 39 significant (FDR < 0.05) genes and 127 significantly (FDR < 0.05) enriched gene sets, which were missed by our previous analyses. Among those, the 10 identified novel genes are part of pathways of kidney development, carbohydrate metabolism, cardiac septum development and glucose metabolism. These results highlight the utility of re-imputing from denser reference panels, until whole-genome sequencing becomes feasible in large samples.


Assuntos
Biologia Computacional/métodos , Loci Gênicos , Rim/fisiologia , Frequência do Gene , Genoma Humano , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Humanos , Polimorfismo de Nucleotídeo Único
10.
Brain ; 140(3): 555-567, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28073787

RESUMO

Itch is thought to represent the peculiar response to stimuli conveyed by somatosensory pathways shared with pain through the activation of specific neurons and receptors. It can occur in association with dermatological, systemic and neurological diseases, or be the side effect of certain drugs. However, some patients suffer from chronic idiopathic itch that is frequently ascribed to psychological distress and for which no biomarker is available to date. We investigated three multigenerational families, one of which diagnosed with joint hypermobility syndrome/Ehlers-Danlos syndrome hypermobility type (JHS/EDS-HT), characterized by idiopathic chronic itch with predominantly proximal distribution. Skin biopsy was performed in all eight affected members and revealed in six of them reduced intraepidermal nerve fibre density consistent with small fibre neuropathy. Whole exome sequencing identified two COL6A5 rare variants co-segregating with chronic itch in eight affected members and absent in non-affected members, and in one unrelated sporadic patient with type 1 painless diabetic neuropathy and chronic itch. Two families and the diabetic patient carried the nonsense c.6814G>T (p.Glu2272*) variant and another family carried the missense c.6486G>C (p.Arg2162Ser) variant. Both variants were predicted as likely pathogenic by in silico analyses. The two variants were rare (minor allele frequency < 0.1%) in 6271 healthy controls and absent in 77 small fibre neuropathy and 167 JHS/EDS-HT patients without itch. Null-allele test on cDNA from patients' fibroblasts of both families carrying the nonsense variant demonstrated functional haploinsufficiency due to activation of nonsense mediated RNA decay. Immunofluorescence microscopy and western blotting revealed marked disorganization and reduced COL6A5 synthesis, respectively. Indirect immunofluorescence showed reduced COL6A5 expression in the skin of patients carrying the nonsense variant. Treatment with gabapentinoids provided satisfactory itch relief in the patients carrying the mutations. Our findings first revealed an association between COL6A5 gene and familiar chronic itch, suggesting a new contributor to the pathogenesis of neuropathic itch and identifying a new candidate therapeutic target.


Assuntos
Colágeno Tipo VI/genética , Saúde da Família , Variação Genética/genética , Doenças do Sistema Nervoso Periférico/genética , Prurido/genética , Adulto , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso Periférico/complicações , Prurido/complicações , Prurido/patologia , Pele/inervação , Pele/metabolismo , Pele/patologia
11.
J Clin Endocrinol Metab ; 102(2): 576-582, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-27802094

RESUMO

Objective: To assess the frequency of variants, including biallelic pathogenic variants, in minichromosome maintenance 8 (MCM8) and minichromosome maintenance 9 (MCM9), other genes related to MCM8-MCM9, and DNA damage repair (DDR) pathway in participants with primary ovarian insufficiency (POI). Design: MCM8, MCM9, and genes encoding DDR proteins that have been implicated in reproductive aging were sequenced among POI participants. Setting: Academic research institution. Participants: All were diagnosed with POI prior to age 40 years and presented with elevated follicle-stimulating hormone levels. Interventions: None. Main Outcome Measures: We identified nucleotide variants in MCM8, MCM9, and genes thought to be involved in the DNA damage response pathway and/or implicated in reproductive aging. Results: MCM8 was sequenced in 155 POI participants, whereas MCM9 was sequenced in 151 participants. Three of 155 (2%) participants carried possibly damaging heterozygous variants in MCM8, whereas 7 of 151 (5%) individuals carried possibly damaging heterozygous variants in MCM9. One participant carried a novel homozygous variant, c.1651C>T, p.Gln551*, in MCM9, which is predicted to introduce a premature stop codon in exon 9. Biallelic damaging heterozygous variants in both MCM8 and MCM9 were identified in 1 participant. Of a total of 10 participants carrying damaging heterozygous variants in either MCM8 or MCM9, 2 individuals carried heterozygous damaging variants in genes associated with either MCM8 or MCM9 or the DDR pathway. Conclusions: We identified a significant number of potentially damaging and novel variants in MCM8 and MCM9 among participants with POI and examined multiallelic association with variants in DDR and MCM8-MCM9 interactome genes.


Assuntos
Envelhecimento/genética , Dano ao DNA/genética , Reparo do DNA/genética , Proteínas de Manutenção de Minicromossomo/genética , Insuficiência Ovariana Primária/genética , Adulto , Feminino , Humanos , Análise de Sequência de DNA
12.
Nat Genet ; 48(10): 1279-83, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27548312

RESUMO

We describe a reference panel of 64,976 human haplotypes at 39,235,157 SNPs constructed using whole-genome sequence data from 20 studies of predominantly European ancestry. Using this resource leads to accurate genotype imputation at minor allele frequencies as low as 0.1% and a large increase in the number of SNPs tested in association studies, and it can help to discover and refine causal loci. We describe remote server resources that allow researchers to carry out imputation and phasing consistently and efficiently.


Assuntos
Genótipo , Haplótipos , Polimorfismo de Nucleotídeo Único , Alelos , Técnicas Genéticas , Estudo de Associação Genômica Ampla , Humanos , Internet , Valores de Referência
13.
J Transl Med ; 14: 22, 2016 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-26801900

RESUMO

BACKGROUND: Breast cancer is the most common cancer in women characterized by a high variable clinical outcome among individuals treated with equivalent regimens and novel targeted therapies. In this study, we performed a population based approach intersecting high-throughput genotype data from Friuli Venezia Giulia (FVG) isolated populations with publically available pharmacogenomics information to estimate the frequency of genotypes correlated with responsiveness to breast cancer treatment thus improving the clinical management of this disease in an efficient and cost effective way. METHODS: A list of 80 variants reported to be related to the efficacy or toxicity of breast cancer drugs was obtained from PharmGKB database. Fourty-one were present in FVG, 1000G European (EUR) and ExAC (Non Finnish European) databases. Their frequency was extracted using PLINK software and the differences tested by Fisher's exact test. RESULTS: Statistical analyses revealed that 13 out of the 41 (32 %) variants were significantly different in frequency in our sample as compared to the EUR/ExAC cohorts. For nine variants the available level of evidence (LOE) included polymorphisms related to cyclophosphamide, tamoxifen, doxorubicin, fluorpyrimidine and paclitaxel. In particular, for trastuzumab two variants were detected: (1) rs1801274-G within FCGR2A and associated with decreased efficacy (LOE 2B); (2) rs1136201-G located within ERBB2 and associated with increased toxicity (LOE 3). Both these two variants were underrepresented in the FVG population compared to EUR/ExAC population thus suggesting a high therapeutic index of this drug in our population. Moreover, as regards fluoropyrimidines, the frequency of two polymorphisms within the DPYD gene associated with drug toxicity (e.g., rs2297595-C allele and rs3918290-T allele, LOE 2A and 1, respectively) was extremely low in FVG population thus suggesting that a larger number of FVG patients could benefit from full dosage of fluoropyrimidine therapy. CONCLUSIONS: All these findings increase the overall knowledge on the prevalence of specific variants related with breast cancer treatment responsiveness in FVG population and highlight the importance of assessing gene polymorphisms related with cancer medications in isolated communities.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Predisposição Genética para Doença , Polimorfismo Genético , Medicina de Precisão , Feminino , Frequência do Gene/genética , Genótipo , Geografia , Humanos , Itália , Farmacogenética , Fatores de Risco
15.
Nat Commun ; 5: 4871, 2014 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-25225788

RESUMO

The analysis of rich catalogues of genetic variation from population-based sequencing provides an opportunity to screen for functional effects. Here we report a rare variant in APOC3 (rs138326449-A, minor allele frequency ~0.25% (UK)) associated with plasma triglyceride (TG) levels (-1.43 s.d. (s.e.=0.27 per minor allele (P-value=8.0 × 10(-8))) discovered in 3,202 individuals with low read-depth, whole-genome sequence. We replicate this in 12,831 participants from five additional samples of Northern and Southern European origin (-1.0 s.d. (s.e.=0.173), P-value=7.32 × 10(-9)). This is consistent with an effect between 0.5 and 1.5 mmol l(-1) dependent on population. We show that a single predicted splice donor variant is responsible for association signals and is independent of known common variants. Analyses suggest an independent relationship between rs138326449 and high-density lipoprotein (HDL) levels. This represents one of the first examples of a rare, large effect variant identified from whole-genome sequencing at a population scale.


Assuntos
Alelos , Apolipoproteína C-III/genética , Lipoproteínas VLDL/sangue , Triglicerídeos/sangue , Processamento Alternativo , Criança , Grupo com Ancestrais do Continente Europeu , Feminino , Frequência do Gene , Humanos , Lipoproteínas HDL/sangue , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Gêmeos/genética
16.
PLoS Genet ; 10(4): e1004234, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24743097

RESUMO

Many existing cohorts contain a range of relatedness between genotyped individuals, either by design or by chance. Haplotype estimation in such cohorts is a central step in many downstream analyses. Using genotypes from six cohorts from isolated populations and two cohorts from non-isolated populations, we have investigated the performance of different phasing methods designed for nominally 'unrelated' individuals. We find that SHAPEIT2 produces much lower switch error rates in all cohorts compared to other methods, including those designed specifically for isolated populations. In particular, when large amounts of IBD sharing is present, SHAPEIT2 infers close to perfect haplotypes. Based on these results we have developed a general strategy for phasing cohorts with any level of implicit or explicit relatedness between individuals. First SHAPEIT2 is run ignoring all explicit family information. We then apply a novel HMM method (duoHMM) to combine the SHAPEIT2 haplotypes with any family information to infer the inheritance pattern of each meiosis at all sites across each chromosome. This allows the correction of switch errors, detection of recombination events and genotyping errors. We show that the method detects numbers of recombination events that align very well with expectations based on genetic maps, and that it infers far fewer spurious recombination events than Merlin. The method can also detect genotyping errors and infer recombination events in otherwise uninformative families, such as trios and duos. The detected recombination events can be used in association scans for recombination phenotypes. The method provides a simple and unified approach to haplotype estimation, that will be of interest to researchers in the fields of human, animal and plant genetics.


Assuntos
Haplótipos/genética , Mapeamento Cromossômico/métodos , Efeito de Coortes , Família , Genótipo , Humanos , Modelos Genéticos , Linhagem , Fenótipo , Recombinação Genética/genética
17.
PLoS Genet ; 10(2): e1004123, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24586183

RESUMO

Autoimmune thyroid diseases (AITD) are common, affecting 2-5% of the general population. Individuals with positive thyroid peroxidase antibodies (TPOAbs) have an increased risk of autoimmune hypothyroidism (Hashimoto's thyroiditis), as well as autoimmune hyperthyroidism (Graves' disease). As the possible causative genes of TPOAbs and AITD remain largely unknown, we performed GWAS meta-analyses in 18,297 individuals for TPOAb-positivity (1769 TPOAb-positives and 16,528 TPOAb-negatives) and in 12,353 individuals for TPOAb serum levels, with replication in 8,990 individuals. Significant associations (P<5×10(-8)) were detected at TPO-rs11675434, ATXN2-rs653178, and BACH2-rs10944479 for TPOAb-positivity, and at TPO-rs11675434, MAGI3-rs1230666, and KALRN-rs2010099 for TPOAb levels. Individual and combined effects (genetic risk scores) of these variants on (subclinical) hypo- and hyperthyroidism, goiter and thyroid cancer were studied. Individuals with a high genetic risk score had, besides an increased risk of TPOAb-positivity (OR: 2.18, 95% CI 1.68-2.81, P = 8.1×10(-8)), a higher risk of increased thyroid-stimulating hormone levels (OR: 1.51, 95% CI 1.26-1.82, P = 2.9×10(-6)), as well as a decreased risk of goiter (OR: 0.77, 95% CI 0.66-0.89, P = 6.5×10(-4)). The MAGI3 and BACH2 variants were associated with an increased risk of hyperthyroidism, which was replicated in an independent cohort of patients with Graves' disease (OR: 1.37, 95% CI 1.22-1.54, P = 1.2×10(-7) and OR: 1.25, 95% CI 1.12-1.39, P = 6.2×10(-5)). The MAGI3 variant was also associated with an increased risk of hypothyroidism (OR: 1.57, 95% CI 1.18-2.10, P = 1.9×10(-3)). This first GWAS meta-analysis for TPOAbs identified five newly associated loci, three of which were also associated with clinical thyroid disease. With these markers we identified a large subgroup in the general population with a substantially increased risk of TPOAbs. The results provide insight into why individuals with thyroid autoimmunity do or do not eventually develop thyroid disease, and these markers may therefore predict which TPOAb-positives are particularly at risk of developing clinical thyroid dysfunction.


Assuntos
Autoanticorpos/genética , Doença de Graves/genética , Doença de Hashimoto/genética , Iodeto Peroxidase/genética , Autoanticorpos/isolamento & purificação , Loci Gênicos , Estudo de Associação Genômica Ampla , Doença de Graves/patologia , Doença de Hashimoto/patologia , Humanos , Iodeto Peroxidase/imunologia , Fatores de Risco , Tireoidite Autoimune , Tireotropina/metabolismo
18.
J Am Soc Nephrol ; 25(8): 1869-82, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24578125

RESUMO

Uromodulin is expressed exclusively in the thick ascending limb and is the most abundant protein excreted in normal urine. Variants in UMOD, which encodes uromodulin, are associated with renal function, and urinary uromodulin levels may be a biomarker for kidney disease. However, the genetic factors regulating uromodulin excretion are unknown. We conducted a meta-analysis of urinary uromodulin levels to identify associated common genetic variants in the general population. We included 10,884 individuals of European descent from three genetic isolates and three urban cohorts. Each study measured uromodulin indexed to creatinine and conducted linear regression analysis of approximately 2.5 million single nucleotide polymorphisms using an additive model. We also tested whether variants in genes expressed in the thick ascending limb associate with uromodulin levels. rs12917707, located near UMOD and previously associated with renal function and CKD, had the strongest association with urinary uromodulin levels (P<0.001). In all cohorts, carriers of a G allele of this variant had higher uromodulin levels than noncarriers did (geometric means 10.24, 14.05, and 17.67 µg/g creatinine for zero, one, or two copies of the G allele). rs12446492 in the adjacent gene PDILT (protein disulfide isomerase-like, testis expressed) also reached genome-wide significance (P<0.001). Regarding genes expressed in the thick ascending limb, variants in KCNJ1, SORL1, and CAB39 associated with urinary uromodulin levels. These data indicate that common variants in the UMOD promoter region may influence urinary uromodulin levels. They also provide insights into uromodulin biology and the association of UMOD variants with renal function.


Assuntos
Grupo com Ancestrais do Continente Europeu/genética , Variação Genética/genética , Uromodulina/urina , Creatinina/metabolismo , Humanos , Polimorfismo de Nucleotídeo Único/genética , Uromodulina/genética
19.
J Proteomics ; 76 Spec No.: 28-35, 2012 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-22951294

RESUMO

Hepcidin, a 25 amino-acid liver hormone, has recently emerged as the key regulator of iron homeostasis. Proteomic studies in limited number of subjects have shown that biological fluids can also contain truncated isoforms, whose role remains to be elucidated. We report, for the first time, data about serum levels of the hepcidin-20 isoform (hep-20) in a general population, taking advantage of the Val Borbera (VB) study where hepcidin-25 (hep-25) was measured by SELDI-TOF-MS. Detectable amount of hep-20 were found in sera from 854 out of 1577 subjects (54.2%), and its levels were about 14% of hep-25 levels. A small fraction of subjects (n=30, 1.9%) had detectable hep-20 but undetectable hep-25. In multivariate regression models, significant predictors of hep-20 were hep-25 and age in males, and hep-25, age, serum ferritin and body mass index in females. Of note, the hep-25:hep-20 ratio was not constant in the VB population, but increased progressively with increasing ferritin levels. This is not consistent with the simplistic view of hep-20 as a mere catabolic byproduct of hep-25. Although a possible active regulation of hep-20 production needs further confirmation, our results may also have implications for immunoassays for serum hepcidin based on antibodies lacking specificity for hep-25. This article is part of a Special Issue entitled: Integrated omics.


Assuntos
Peptídeos Catiônicos Antimicrobianos/sangue , Fragmentos de Peptídeos/sangue , Caracteres Sexuais , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hepcidinas , Humanos , Masculino , Pessoa de Meia-Idade , Isoformas de Proteínas/sangue , Proteômica/métodos , Análise de Regressão
20.
J Med Genet ; 48(9): 629-34, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21785125

RESUMO

BACKGROUND: Hepcidin is the main regulator of iron homeostasis: inappropriate production of hepcidin results in iron overload or iron deficiency and anaemia. AIMS: To study variation of serum hepcidin concentration in a normal population. RESULTS: Hepcidin showed age and sex dependent variations that correlated with ferritin but not with serum iron and transferrin saturation. The size of the study population was underpowered to find genome wide significant associations with hepcidin concentrations but it allowed to show that association with serum iron, transferrin saturation and erythrocyte traits of common DNA variants in HFE (rs1800562) and TMPRSS6 (rs855791) genes is not exclusively dependent on hepcidin values. When multiple interactions between environmental factors, the iron parameters and hepcidin were taken into account, the HFE variant, and to lesser extent the TMPRSS6 variant, were associated with ferritin and with hepcidin normalised to ferritin (the hepcidin/ferritin ratio). CONCLUSIONS: The results suggest a mutual control of serum hepcidin and ferritin concentrations, a mechanism relevant to the pathophysiology of HFE haemochromatosis, and demonstrate that the HFE rs1800562 C282Y variant exerts a direct pleiotropic effect on the iron parameters, in part independent of hepcidin.


Assuntos
Peptídeos Catiônicos Antimicrobianos/sangue , Eritrócitos/metabolismo , Variação Genética , Antígenos de Histocompatibilidade Classe I/genética , Ferro/sangue , Proteínas de Membrana/genética , Serina Endopeptidases/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Ferritinas/sangue , Proteína da Hemocromatose , Hepcidinas , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
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