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1.
Nat Commun ; 12(1): 6147, 2021 10 22.
Artículo en Inglés | MEDLINE | ID: mdl-34686674

RESUMEN

Joint fine-mapping that leverages information between quantitative traits could improve accuracy and resolution over single-trait fine-mapping. Using summary statistics, flashfm (flexible and shared information fine-mapping) fine-maps signals for multiple traits, allowing for missing trait measurements and use of related individuals. In a Bayesian framework, prior model probabilities are formulated to favour model combinations that share causal variants to capitalise on information between traits. Simulation studies demonstrate that both approaches produce broadly equivalent results when traits have no shared causal variants. When traits share at least one causal variant, flashfm reduces the number of potential causal variants by 30% compared with single-trait fine-mapping. In a Ugandan cohort with 33 cardiometabolic traits, flashfm gave a 20% reduction in the total number of potential causal variants from single-trait fine-mapping. Here we show flashfm is computationally efficient and can easily be deployed across publicly available summary statistics for signals in up to six traits.


Asunto(s)
Mapeo Cromosómico/métodos , Estudio de Asociación del Genoma Completo/métodos , Teorema de Bayes , Simulación por Computador , Genoma Humano , Humanos , Desequilibrio de Ligamiento , Modelos Genéticos , Fenotipo , Polimorfismo de Nucleótido Simple , Sitios de Carácter Cuantitativo
2.
BMC Cardiovasc Disord ; 20(1): 468, 2020 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-33129260

RESUMEN

BACKGROUND: This study aimed to evaluate atrium extracellular matrix remodeling in atrial fibrillation (AF) patients with severe aortic stenosis, through histological fibrosis quantification and extracellular matrix gene expression analysis, as well as serum quantification of selected protein targets. METHODS: A posthoc analysis of a prospective study was performed in a cohort of aortic stenosis patients. Between 2014 and 2019, 56 patients with severe aortic stenosis submitted to aortic valve replacement surgery in a tertiary hospital were selected. RESULTS: Fibrosis was significantly increased in the AF group when compared to sinus rhythm (SR) patients (p = 0.024). Moreover, cardiomyocyte area was significantly higher in AF patients versus SR patients (p = 0.008). Conversely, collagen III gene expression was increased in AF patients (p = 0.038). TIMP1 was less expressed in the atria of AF patients. MMP16/TIMP4 ratio was significantly decreased in AF patients (p = 0.006). TIMP1 (p = 0.004) and TIMP2 (p = 0.012) were significantly increased in the serum of AF patients. Aortic valve maximum (p = 0.0159) and mean (p = 0.031) gradients demonstrated a negative association with serum TIMP1. CONCLUSIONS: Atrial fibrillation patients with severe aortic stenosis present increased atrial fibrosis and collagen type III synthesis, with extracellular matrix remodelling demonstrated by a decrease in the MMP16/TIMP4 ratio, along with an increased serum TIMP1 and TIMP2 proteins.


Asunto(s)
Estenosis de la Válvula Aórtica/patología , Remodelación Atrial , Matriz Extracelular/patología , Atrios Cardíacos/patología , Anciano , Anciano de 80 o más Años , Estenosis de la Válvula Aórtica/sangre , Estenosis de la Válvula Aórtica/fisiopatología , Biomarcadores/análisis , Biomarcadores/sangre , Matriz Extracelular/química , Femenino , Fibrosis , Atrios Cardíacos/química , Atrios Cardíacos/fisiopatología , Humanos , Masculino , Metaloproteinasa 16 de la Matriz/análisis , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Inhibidor Tisular de Metaloproteinasa-1/análisis , Inhibidor Tisular de Metaloproteinasa-1/sangre , Inhibidor Tisular de Metaloproteinasa-2/sangre , Inhibidores Tisulares de Metaloproteinasas/análisis , Inhibidor Tisular de Metaloproteinasa-4
3.
Obes Surg ; 30(2): 673-680, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31749108

RESUMEN

INTRODUCTION: Several reports highlight bariatric surgery as an efficient and long-lasting strategy for weight loss. Herein, we aimed to evaluate the impact of bariatric surgery on 10-year cardiovascular disease (CVD) risk and to compare the effectiveness of different surgical procedures, employing the Framingham Risk Score (FRS). METHODS: Retrospective longitudinal observational study of patients undergoing bariatric surgery. Data was assessed preoperatively and during a 4-year follow-up period. RESULTS: We evaluated 1449 individuals, 85.2% female, age of 42.4 ± 10.6 years, and preoperative BMI of 44.3 ± 5.8 kg/m2; 58.0% underwent Roux-en-Y gastric bypass (RYGB), 23.4% sleeve gastrectomy (SG), and 18.6% adjustable gastric band (AGB). The 10-year CVD risk decreased 43.6% in the first postoperative year. The decrease in FRS was more pronounced in the RYGB group (50.5% in the first postoperative year) (p < 0.001). Although there was a subsequent slight increase in FRS during the follow-up period, the cardiovascular benefits were maintained when compared with baseline. For all surgical procedures, CVD risk showed a quadratic trend with a J-shaped curve. A negative interaction between the RYGB group CVD risk and time was observed (ß = - 0.072 (95% CI, - 0.109; - 0.035)). In the RYGB group, FRS decreased more when compared with the SG and AGB groups and, from the second postoperative year onwards, increased more slowly, regardless of gender. The SG group showed similar trend as that of the AGB (ß = - 0.002 (95% CI, - 0.049; 0.053)). CONCLUSION: Our study showed a significant reduction of 10-year CVD risk after bariatric surgery. This decrease was more pronounced in the first postoperative year, and RYGB was the procedure with the greatest decrease of the 10-year CVD risk.


Asunto(s)
Cirugía Bariátrica , Factores de Riesgo de Enfermedad Cardiaca , Obesidad Mórbida/cirugía , Adulto , Cirugía Bariátrica/efectos adversos , Cirugía Bariátrica/métodos , Cirugía Bariátrica/estadística & datos numéricos , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/prevención & control , Femenino , Estudios de Seguimiento , Gastrectomía/efectos adversos , Gastrectomía/métodos , Gastrectomía/estadística & datos numéricos , Derivación Gástrica/efectos adversos , Derivación Gástrica/métodos , Derivación Gástrica/estadística & datos numéricos , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Obesidad Mórbida/complicaciones , Obesidad Mórbida/epidemiología , Portugal/epidemiología , Periodo Posoperatorio , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento , Pérdida de Peso/fisiología
4.
Food Res Int ; 123: 373-382, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31284989

RESUMEN

The main goal of this work was to approach food industry conditions in the comparison of the susceptibility of biofilms of Listeria monocytogenes to the biocides benzalkonium chloride (BAC) and peracetic acid (PAA). Twelve isolates of L. monocytogenes, including nine well characterized BAC resistant strains were used. Biofilms were produced on stainless steel coupons (SSC), at 11 °C (refrigeration temperature) or at 25 °C (room temperature), in culture media simulating clean (nutrient limiting) or soiled (nutrient rich) growth conditions. Neither different nutrient availability nor growth temperature showed significant effect (p > .05) on biofilm formation. PAA confirmed to be more effective than BAC in biofilm elimination. Biofilms formed under nutritional stress tended to differentiate more the response to BAC of the resistant or sensitive strains, but the resistant or sensitive phenotype of the planktonic cells did not dictate biofilm susceptibility.


Asunto(s)
Compuestos de Benzalconio/farmacología , Biopelículas/efectos de los fármacos , Listeria monocytogenes/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Recuento de Colonia Microbiana , Desinfectantes/farmacología , Farmacorresistencia Bacteriana Múltiple , Contaminación de Alimentos , Manipulación de Alimentos , Microbiología de Alimentos , Listeria monocytogenes/metabolismo , Pruebas de Sensibilidad Microbiana , Ácido Peracético/farmacología , Análisis de Componente Principal , Acero Inoxidable
5.
Arq. bras. med. vet. zootec. (Online) ; 70(2): 633-636, mar.-abr. 2018.
Artículo en Portugués | LILACS, VETINDEX | ID: biblio-910976

RESUMEN

A 6-month-old female, 1.0kg, uncastrated female Persian cat was brought to the Veterinary Hospital at State University of Ceara, with a history of dyspnea, prostration, hyporexia and progressive weight loss for a month. On physical examination, systolic cardiac murmur, cyanosis and dyspnea were detected. Unfortunately, the cat died during oxygen therapy. Necropsy examination revealed an increase in cardiac silhouette and ventricular septal defect of 2cm in diameter. Macroscopically the lungs were collapsed, with absent and diffusely reddish blackish crepitus, and the liver with blackish red coalescent multifocal areas, interspersed with lighter areas and lobular pattern with irregular brownish multifocal areas intercepted by brownish areas. Thus, the necropsy results together with the history and physical examination of the animal confirmed the diagnosis of Eisenmenger Syndrome, becoming the report of the first case, in a cat, in Brazil.(AU)


Asunto(s)
Animales , Femenino , Gatos , Gatos/anomalías , Complejo de Eisenmenger/clasificación , Complejo de Eisenmenger/diagnóstico , Defectos del Tabique Interventricular/veterinaria
6.
Artículo en Inglés | MEDLINE | ID: mdl-29868224

RESUMEN

Epstein Barr virus (EBV) infects 95% of the global population and is associated with up to 2% of cancers globally. Immunoglobulin G (IgG) antibody levels to EBV have been shown to be heritable and associated with developing malignancies. We, therefore, performed a pilot genome-wide association analysis of anti-EBV IgG traits in an African population, using a combined approach including array genotyping, whole-genome sequencing and imputation to a panel with African sequence data. In 1562 Ugandans, we identify a variant in human leukocyte antigen (HLA)-DQA1, rs9272371 (p = 2.6 × 10-17) associated with anti-EBV nuclear antigen-1 responses. Trans-ancestry meta-analysis and fine-mapping with European-ancestry individuals suggest the presence of distinct HLA class II variants driving associations in Uganda. In addition, we identify four putative, novel, very rare African-specific loci with preliminary evidence for association with anti-viral capsid antigen IgG responses which will require replication for validation. These findings reinforce the need for the expansion of such studies in African populations with relevant datasets to capture genetic diversity.

7.
Int J Obes (Lond) ; 40(9): 1346-52, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27121252

RESUMEN

BACKGROUND: Recent cross-sectional genome-wide scans have reported associations of 97 independent loci with body mass index (BMI). In 3541 middle-aged adult participants from the GLACIER Study, we tested whether these loci are associated with 10-year changes in BMI and other cardiometabolic traits (fasting and 2-h glucose, triglycerides, total cholesterol, and systolic and diastolic blood pressures). METHODS: A BMI-specific genetic risk score (GRS) was calculated by summing the BMI-associated effect alleles at each locus. Trait-specific cardiometabolic GRSs comprised only the loci that show nominal association (P⩽0.10) with the respective trait in the original cross-sectional study. In longitudinal genetic association analyses, the second visit trait measure (assessed ~10 years after baseline) was used as the dependent variable and the models were adjusted for the baseline measure of the outcome trait, age, age(2), fasting time (for glucose and lipid traits), sex, follow-up time and population substructure. RESULTS: The BMI-specific GRS was associated with increased BMI at follow-up (ß=0.014 kg m(-2) per allele per 10-year follow-up, s.e.=0.006, P=0.019) as were three loci (PARK2 rs13191362, P=0.005; C6orf106 rs205262, P=0.043; and C9orf93 rs4740619, P=0.01). Although not withstanding Bonferroni correction, a handful of single-nucleotide polymorphisms was nominally associated with changes in blood pressure, glucose and lipid levels. CONCLUSIONS: Collectively, established BMI-associated loci convey modest but statistically significant time-dependent associations with long-term changes in BMI, suggesting a role for effect modification by factors that change with time in this population.


Asunto(s)
Índice de Masa Corporal , Predisposición Genética a la Enfermedad/genética , Estudio de Asociación del Genoma Completo , Obesidad/complicaciones , Obesidad/genética , Polimorfismo de Nucleótido Simple/genética , Presión Sanguínea , Colesterol/sangre , Estudios Transversales , Ayuno , Femenino , Predisposición Genética a la Enfermedad/epidemiología , Variación Genética , Genotipo , Glucosa/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Obesidad/sangre , Obesidad/epidemiología , Fenotipo , Estudios Prospectivos , Triglicéridos/sangre
8.
Diabetes ; 64(1): 299-310, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25114292

RESUMEN

Perilipin 1 is a lipid droplet coat protein predominantly expressed in adipocytes, where it inhibits basal and facilitates stimulated lipolysis. Loss-of-function mutations in the PLIN1 gene were recently reported in patients with a novel subtype of familial partial lipodystrophy, designated as FPLD4. We now report the identification and characterization of a novel heterozygous frameshift mutation affecting the carboxy-terminus (439fs) of perilipin 1 in two unrelated families. The mutation cosegregated with a similar phenotype including partial lipodystrophy, severe insulin resistance and type 2 diabetes, extreme hypertriglyceridemia, and nonalcoholic fatty liver disease in both families. Poor metabolic control despite maximal medical therapy prompted two patients to undergo bariatric surgery, with remarkably beneficial consequences. Functional studies indicated that expression levels of the mutant protein were lower than wild-type protein, and in stably transfected preadipocytes the mutant protein was associated with smaller lipid droplets. Interestingly, unlike the previously reported 398 and 404 frameshift mutants, this variant binds and stabilizes ABHD5 expression but still fails to inhibit basal lipolysis as effectively as wild-type perilipin 1. Collectively, these findings highlight the physiological need for exquisite regulation of neutral lipid storage within adipocyte lipid droplets, as well as the possible metabolic benefits of bariatric surgery in this serious disease.


Asunto(s)
Proteínas Portadoras/genética , Diabetes Mellitus Tipo 2/genética , Mutación del Sistema de Lectura , Hiperlipoproteinemia Tipo IV/genética , Lipodistrofia Parcial Familiar/genética , Fosfoproteínas/genética , 1-Acilglicerol-3-Fosfato O-Aciltransferasa/metabolismo , Células 3T3-L1 , Adipocitos Blancos/fisiología , Adolescente , Adulto , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Proteínas Portadoras/metabolismo , Salud de la Familia , Femenino , Humanos , Resistencia a la Insulina/genética , Masculino , Ratones , Persona de Mediana Edad , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Linaje , Perilipina-1 , Fosfoproteínas/metabolismo
9.
Diabetologia ; 56(1): 60-9, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23052052

RESUMEN

AIMS/HYPOTHESIS: Although a family history of type 2 diabetes is a strong risk factor for the disease, the factors mediating this excess risk are poorly understood. In the InterAct case-cohort study, we investigated the association between a family history of diabetes among different family members and the incidence of type 2 diabetes, as well as the extent to which genetic, anthropometric and lifestyle risk factors mediated this association. METHODS: A total of 13,869 individuals (including 6,168 incident cases of type 2 diabetes) had family history data available, and 6,887 individuals had complete data on all mediators. Country-specific Prentice-weighted Cox models were fitted within country, and HRs were combined using random effects meta-analysis. Lifestyle and anthropometric measurements were performed at baseline, and a genetic risk score comprising 35 polymorphisms associated with type 2 diabetes was created. RESULTS: A family history of type 2 diabetes was associated with a higher incidence of the condition (HR 2.72, 95% CI 2.48, 2.99). Adjustment for established risk factors including BMI and waist circumference only modestly attenuated this association (HR 2.44, 95% CI 2.03, 2.95); the genetic score alone explained only 2% of the family history-associated risk of type 2 diabetes. The greatest risk of type 2 diabetes was observed in those with a biparental history of type 2 diabetes (HR 5.14, 95% CI 3.74, 7.07) and those whose parents had been diagnosed with diabetes at a younger age (<50 years; HR 4.69, 95% CI 3.35, 6.58), an effect largely confined to a maternal family history. CONCLUSIONS/INTERPRETATION: Prominent lifestyle, anthropometric and genetic risk factors explained only a marginal proportion of the excess risk associated with family history, highlighting the fact that family history remains a strong, independent and easily assessed risk factor for type 2 diabetes. Discovering factors that will explain the association of family history with type 2 diabetes risk will provide important insight into the aetiology of type 2 diabetes.


Asunto(s)
Diabetes Mellitus Tipo 2/epidemiología , Salud de la Familia , Estilo de Vida , Actividad Motora , Adulto , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Estudios de Casos y Controles , Estudios de Cohortes , Estudios Transversales , Diabetes Mellitus Tipo 2/etnología , Diabetes Mellitus Tipo 2/etiología , Diabetes Mellitus Tipo 2/genética , Europa (Continente)/epidemiología , Salud de la Familia/etnología , Femenino , Estudios de Seguimiento , Predisposición Genética a la Enfermedad , Humanos , Incidencia , Estilo de Vida/etnología , Masculino , Persona de Mediana Edad , Madres , Factores de Riesgo , Circunferencia de la Cintura , Adulto Joven
10.
Science ; 334(6055): 474, 2011 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-21979934

RESUMEN

Pathological fasting hypoglycemia in humans is usually explained by excessive circulating insulin or insulin-like molecules or by inborn errors of metabolism impairing liver glucose production. We studied three unrelated children with unexplained, recurrent, and severe fasting hypoglycemia and asymmetrical growth. All were found to carry the same de novo mutation, p.Glu17Lys, in the serine/threonine kinase AKT2, in two cases as heterozygotes and in one case in mosaic form. In heterologous cells, the mutant AKT2 was constitutively recruited to the plasma membrane, leading to insulin-independent activation of downstream signaling. Thus, systemic metabolic disease can result from constitutive, cell-autonomous activation of signaling pathways normally controlled by insulin.


Asunto(s)
Hipoglucemia/genética , Hipoglucemia/metabolismo , Mutación , Proteínas Proto-Oncogénicas c-akt/genética , Sustitución de Aminoácidos , Membrana Celular/metabolismo , Núcleo Celular/metabolismo , Niño , Femenino , Crecimiento , Células HeLa , Heterocigoto , Humanos , Insulina/sangre , Insulina/metabolismo , Masculino , Mosaicismo , Linaje , Dominios y Motivos de Interacción de Proteínas , Proteínas Proto-Oncogénicas c-akt/química , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal
11.
Diabetologia ; 54(9): 2272-82, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21717116

RESUMEN

AIMS/HYPOTHESIS: Studying gene-lifestyle interaction may help to identify lifestyle factors that modify genetic susceptibility and uncover genetic loci exerting important subgroup effects. Adequately powered studies with prospective, unbiased, standardised assessment of key behavioural factors for gene-lifestyle studies are lacking. This case-cohort study aims to investigate how genetic and potentially modifiable lifestyle and behavioural factors, particularly diet and physical activity, interact in their influence on the risk of developing type 2 diabetes. METHODS: Incident cases of type 2 diabetes occurring in European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts between 1991 and 2007 from eight of the ten EPIC countries were ascertained and verified. Prentice-weighted Cox regression and random-effects meta-analyses were used to investigate differences in diabetes incidence by age and sex. RESULTS: A total of 12,403 verified incident cases of type 2 diabetes occurred during 3.99 million person-years of follow-up of 340,234 EPIC participants eligible for InterAct. We defined a centre-stratified subcohort of 16,154 individuals for comparative analyses. Individuals with incident diabetes who were randomly selected into the subcohort (n = 778) were included as cases in the analyses. All prevalent diabetes cases were excluded from the study. InterAct cases were followed-up for an average of 6.9 years; 49.7% were men. Mean baseline age and age at diagnosis were 55.6 and 62.5 years, mean BMI and waist circumference values were 29.4 kg/m(2) and 102.7 cm in men, and 30.1 kg/m(2) and 92.8 cm in women, respectively. Risk of type 2 diabetes increased linearly with age, with an overall HR of 1.56 (95% CI 1.48-1.64) for a 10 year age difference, adjusted for sex. A male excess in the risk of incident diabetes was consistently observed across all countries, with a pooled HR of 1.51 (95% CI 1.39-1.64), adjusted for age. CONCLUSIONS/INTERPRETATION: InterAct is a large, well-powered, prospective study that will inform our understanding of the interplay between genes and lifestyle factors on the risk of type 2 diabetes development.


Asunto(s)
Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/genética , Predisposición Genética a la Enfermedad/genética , Estilo de Vida , Estudios de Cohortes , Diabetes Mellitus Tipo 2/fisiopatología , Dieta , Europa (Continente)/epidemiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Cooperación Internacional , Masculino , Persona de Mediana Edad , Actividad Motora/fisiología , Estudios Prospectivos , Estudios Retrospectivos , Factores de Riesgo
12.
Diabetologia ; 54(5): 1057-65, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21318406

RESUMEN

AIMS/HYPOTHESIS: Genetic insulin receptoropathies are a rare cause of severe insulin resistance. We identified the Ile119Met missense mutation in the insulin receptor INSR gene, previously reported in a Yemeni kindred, in four unrelated patients with Somali ancestry. We aimed to investigate a possible genetic founder effect, and to study the mechanism of loss of function of the mutant receptor. METHODS: Biochemical profiling and DNA haplotype analysis of affected patients were performed. Insulin receptor expression in lymphoblastoid cells from a homozygous p.Ile119Met INSR patient, and in cells heterologously expressing the mutant receptor, was examined. Insulin binding, insulin-stimulated receptor autophosphorylation, and cooperativity and pH dependency of insulin dissociation were also assessed. RESULTS: All patients had biochemical profiles pathognomonic of insulin receptoropathy, while haplotype analysis revealed the putative shared region around the INSR mutant to be no larger than 28 kb. An increased insulin proreceptor to ß subunit ratio was seen in patient-derived cells. Steady state insulin binding and insulin-stimulated autophosphorylation of the mutant receptor was normal; however it exhibited decreased insulin dissociation rates with preserved cooperativity, a difference accentuated at low pH. CONCLUSIONS/INTERPRETATION: The p.Ile119Met INSR appears to have arisen around the Horn of Africa, and should be sought first in severely insulin resistant patients with ancestry from this region. Despite collectively compelling genetic, clinical and biochemical evidence for its pathogenicity, loss of function in conventional in vitro assays is subtle, suggesting mildly impaired receptor recycling only.


Asunto(s)
Resistencia a la Insulina/fisiología , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Adulto , África , Células Cultivadas , Niño , Femenino , Haplotipos , Humanos , Lactante , Resistencia a la Insulina/genética , Masculino , Mutagénesis Sitio-Dirigida , Mutación , Reacción en Cadena de la Polimerasa , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Adulto Joven
13.
J Inherit Metab Dis ; 33 Suppl 3: S227-32, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20521171

RESUMEN

In Npc1 null mice, a model for Niemann Pick Disease Type C1, it has been reported that hepatocyte insulin receptor function is significantly impaired, consistent with growing evidence that membrane fluidity and microdomain structure have an important role in insulin signal transduction. However, whether insulin receptor function is also compromised in human Niemann Pick disease Type C1 is unclear. We now report a girl who developed progressive dementia, ataxia and opthalmoplegia from 9 years old, followed by severe acanthosis nigricans, hirsutism and acne at 11 years old. She was diagnosed with Niemann Pick Disease type C1 (OMIM#257220) based on positive filipin staining and reduced cholesterol-esterifying activity in dermal fibroblasts, and homozygosity for the p.Ile1061Thr NPC1 mutation. Further analysis revealed her also to be heterozygous for a novel trinucleotide deletion (c.3659 + 1_3659 + 3delGTG) at the end of exon 20 of INSR, encoding the insulin receptor, leading to deletion of Trp1193 in the intracellular tyrosine kinase domain. INSR mRNA and protein levels were normal in dermal fibroblasts, consistent with a primary signal transduction defect in the mutant receptor. Although the proband was significantly more insulin resistant than her father, who carried the INSR mutation but was only heterozygous for the NPC1 variant, their respective degrees of IR were very similar to those previously reported in a father-daughter pair with the closely related p.Trp1193Leu INSR mutation. This suggests that loss of NPC1 function, with attendant changes in membrane cholesterol composition, does not significantly modify the IR phenotype, even in the context of severely impaired INSR function.


Asunto(s)
Antígenos CD/genética , Proteínas Portadoras/genética , Resistencia a la Insulina/genética , Glicoproteínas de Membrana/genética , Mutación , Enfermedad de Niemann-Pick Tipo C/genética , Receptor de Insulina/genética , Adulto , Anciano , Secuencia de Aminoácidos , Antígenos CD/metabolismo , Biomarcadores/sangre , Células Cultivadas , Niño , Análisis Mutacional de ADN , Femenino , Fibroblastos/metabolismo , Predisposición Genética a la Enfermedad , Herencia , Heterocigoto , Homocigoto , Humanos , Péptidos y Proteínas de Señalización Intracelular , Masculino , Datos de Secuencia Molecular , Proteína Niemann-Pick C1 , Enfermedad de Niemann-Pick Tipo C/sangre , Enfermedad de Niemann-Pick Tipo C/diagnóstico , Linaje , Fenotipo , ARN Mensajero/metabolismo , Receptor de Insulina/metabolismo , Índice de Severidad de la Enfermedad
14.
Diabetologia ; 53(10): 2155-62, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20571754

RESUMEN

AIMS/HYPOTHESIS: We determined whether single nucleotide polymorphisms (SNPs) previously associated with diabetogenic traits improve the discriminative power of a type 2 diabetes genetic risk score. METHODS: Participants (n = 2,751) were genotyped for 73 SNPs previously associated with type 2 diabetes, fasting glucose/insulin concentrations, obesity or lipid levels, from which five genetic risk scores (one for each of the four traits and one combining all SNPs) were computed. Type 2 diabetes patients and non-diabetic controls (n = 1,327/1,424) were identified using medical records in addition to an independent oral glucose tolerance test. RESULTS: Model 1, including only SNPs associated with type 2 diabetes, had a discriminative power of 0.591 (p < 1.00 x 10(-20) vs null model) as estimated by the area under the receiver operator characteristic curve (ROC AUC). Model 2, including only fasting glucose/insulin SNPs, had a significantly higher discriminative power than the null model (ROC AUC 0.543; p = 9.38 x 10(-6) vs null model), but lower discriminative power than model 1 (p = 5.92 x 10(-5)). Model 3, with only lipid-associated SNPs, had significantly higher discriminative power than the null model (ROC AUC 0.565; p = 1.44 x 10(-9)) and was not statistically different from model 1 (p = 0.083). The ROC AUC of model 4, which included only obesity SNPs, was 0.557 (p = 2.30 x 10(-7) vs null model) and smaller than model 1 (p = 0.025). Finally, the model including all SNPs yielded a significant improvement in discriminative power compared with the null model (p < 1.0 x 10(-20)) and model 1 (p = 1.32 x 10(-5)); its ROC AUC was 0.626. CONCLUSIONS/INTERPRETATION: Adding SNPs previously associated with fasting glucose, insulin, lipids or obesity to a genetic risk score for type 2 diabetes significantly increases the power to discriminate between people with and without clinically manifest type 2 diabetes compared with a model including only conventional type 2 diabetes loci.


Asunto(s)
Diabetes Mellitus Tipo 2/genética , Predisposición Genética a la Enfermedad , Valor Predictivo de las Pruebas , Población Blanca/genética , Área Bajo la Curva , Glucemia , Femenino , Genotipo , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/genética , Masculino , Persona de Mediana Edad , Modelos Biológicos , Oportunidad Relativa , Polimorfismo de Nucleótido Simple , Curva ROC , Factores de Riesgo , Suecia
16.
Diabetologia ; 52(9): 1846-51, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19526209

RESUMEN

AIMS/HYPOTHESIS: According to the thrifty genotype hypothesis, the high prevalence of type 2 diabetes and obesity is a consequence of genetic variants that have undergone positive selection during historical periods of erratic food supply. The recent expansion in the number of validated type 2 diabetes- and obesity-susceptibility loci, coupled with access to empirical data, enables us to look for evidence in support (or otherwise) of the thrifty genotype hypothesis using proven loci. METHODS: We employed a range of tests to obtain complementary views of the evidence for selection: we determined whether the risk allele at associated 'index' single-nucleotide polymorphisms is derived or ancestral, calculated the integrated haplotype score (iHS) and assessed the population differentiation statistic fixation index (F (ST)) for 17 type 2 diabetes and 13 obesity loci. RESULTS: We found no evidence for significant differences for the derived/ancestral allele test. None of the studied loci showed strong evidence for selection based on the iHS score. We find a high F (ST) for rs7901695 at TCF7L2, the largest type 2 diabetes effect size found to date. CONCLUSIONS/INTERPRETATION: Our results provide some evidence for selection at specific loci, but there are no consistent patterns of selection that provide conclusive confirmation of the thrifty genotype hypothesis. Discovery of more signals and more causal variants for type 2 diabetes and obesity is likely to allow more detailed examination of these issues.


Asunto(s)
Diabetes Mellitus Tipo 2/genética , Predisposición Genética a la Enfermedad , Genotipo , Obesidad/genética , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/epidemiología , Abastecimiento de Alimentos , Frecuencia de los Genes , Humanos , Modelos Genéticos , Obesidad/complicaciones , Obesidad/epidemiología , Polimorfismo de Nucleótido Simple , Prevalencia , Factores de Riesgo , Selección Genética
17.
Diabetologia ; 52(8): 1537-42, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19455304

RESUMEN

AIMS/HYPOTHESIS: We investigated whether variation in MTNR1B, which was recently identified as a common genetic determinant of fasting glucose levels in healthy, diabetes-free individuals, is associated with measures of beta cell function and whole-body insulin sensitivity. METHODS: We studied 1,276 healthy individuals of European ancestry at 19 centres of the Relationship between Insulin Sensitivity and Cardiovascular disease (RISC) study. Whole-body insulin sensitivity was assessed by euglycaemic-hyperinsulinaemic clamp and indices of beta cell function were derived from a 75 g oral glucose tolerance test (including 30 min insulin response and glucose sensitivity). We studied rs10830963 in MTNR1B using additive genetic models, adjusting for age, sex and recruitment centre. RESULTS: The minor (G) allele of rs10830963 in MTNR1B (frequency 0.30 in HapMap Centre d'Etude du Polymorphisme [Utah residents with northern and western European ancestry] [CEU]; 0.29 in RISC participants) was associated with higher levels of fasting plasma glucose (standardised beta [95% CI] 0.17 [0.085, 0.25] per G allele, p = 5.8 x 10(-5)), consistent with recent observations. In addition, the G-allele was significantly associated with lower early insulin response (-0.19 [-0.28, -0.10], p = 1.7 x 10(-5)), as well as with decreased beta cell glucose sensitivity (-0.11 [-0.20, -0.027], p = 0.010). No associations were observed with clamp-assessed insulin sensitivity (p = 0.15) or different measures of body size (p > 0.7 for all). CONCLUSIONS/INTERPRETATION: Genetic variation in MTNR1B is associated with defective early insulin response and decreased beta cell glucose sensitivity, which may contribute to the higher glucose levels of non-diabetic individuals carrying the minor G allele of rs10830963 in MTNR1B.


Asunto(s)
Variación Genética , Prueba de Tolerancia a la Glucosa , Células Secretoras de Insulina/fisiología , Insulina/fisiología , Receptor de Melatonina MT1/genética , Adulto , Femenino , Humanos , Insulina/farmacología , Resistencia a la Insulina/genética , Masculino , Persona de Mediana Edad , Modelos Genéticos , Receptor de Melatonina MT2/genética , Población Blanca/genética
20.
Diabetologia ; 51(3): 458-63, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18040659

RESUMEN

AIMS/HYPOTHESIS: Mutations at the gene encoding wolframin (WFS1) cause Wolfram syndrome, a rare neurological condition. Associations between single nucleotide polymorphisms (SNPs) at WFS1 and type 2 diabetes have recently been reported. Thus, our aim was to replicate those associations in a northern Swedish case-control study of type 2 diabetes. We also performed a meta-analysis of published and previously unpublished data from Sweden, Finland and France, to obtain updated summary effect estimates. METHODS: Four WFS1 SNPs (rs10010131, rs6446482, rs752854 and rs734312 [H611R]) were genotyped in a type 2 diabetes case-control study (n = 1,296/1,412) of Swedish adults. Logistic regression was used to assess the association between each WFS1 SNP and type 2 diabetes, following adjustment for age, sex and BMI. We then performed a meta-analysis of 11 studies of type 2 diabetes, comprising up to 14,139 patients and 16,109 controls, to obtain a summary effect estimate for the WFS1 variants. RESULTS: In the northern Swedish study, the minor allele at rs752854 was associated with reduced type 2 diabetes risk [odds ratio (OR) 0.85, 95% CI 0.75-0.96, p=0.010]. Borderline statistical associations were observed for the remaining SNPs. The meta-analysis of the four independent replication studies for SNP rs10010131 and correlated variants showed evidence for statistical association (OR 0.87, 95% CI 0.82-0.93, p=4.5 x 10(-5)). In an updated meta-analysis of all 11 studies, strong evidence of statistical association was also observed (OR 0.89, 95% CI 0.86-0.92; p=4.9 x 10(-11)). CONCLUSIONS/INTERPRETATION: In this study of WFS1 variants and type 2 diabetes risk, we have replicated the previously reported associations between SNPs at this locus and the risk of type 2 diabetes.


Asunto(s)
Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/genética , Variación Genética , Proteínas de la Membrana/genética , Polimorfismo de Nucleótido Simple , Adulto , ADN/genética , Europa (Continente)/epidemiología , Genotipo , Humanos , Desequilibrio de Ligamiento , Medición de Riesgo , Suecia
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