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1.
Nutr Metab Cardiovasc Dis ; 25(6): 548-55, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25836955

RESUMO

BACKGROUND AND AIMS: Owing to the multiplicity of the key components of metabolic syndrome (MetS), its diagnosis is very complex. The lack of a unique definition is responsible for the prevalence variability observed among studies; therefore, a definition based on continuous variables was recommended. The aim of this study was to compare competing models of the MetS factor structure for selecting the one that explains the best clustering pattern and to propose an algorithm for computing MetS as a continuous variable. METHODS AND RESULTS: Data were from isolated Sardinian populations (n = 8102). Confirmatory factor analysis (CFA) and two-group CFA by gender were performed to evaluate the sex-specific factor structure of MetS. After selecting the best model, an algorithm was obtained using factor loadings/residual variances. The quality of the MetS score was evaluated by the receiver operating characteristics curve and the area under the curve. Cross-validation was performed to validate the score and to determine the best cut point. The best fit model was a bifactor one with a general factor (MetS) and three specific factors (f1: obesity/adiposity trait; f2: hypertension/blood pressure trait; and f3: lipid trait). Gender-specific algorithms were implemented to obtain MetS scores showing a good diagnostic performance (0.80 specificity and 0.80 sensitivity for the cut point). Furthermore, cross-validation confirmed these results. CONCLUSION: These analyses suggested that the bifactor model was the most representative one. In addition, they provided a score and a cut point that are both clinically accessible and interpretable measures for MetS diagnosis and likely useful for evaluating the association with adverse cardiovascular disease and diabetes and for investigating the MetS genetic component.


Assuntos
Marcadores Genéticos , Síndrome Metabólica/epidemiologia , Síndrome Metabólica/genética , Modelos Genéticos , Adiposidade/genética , Adulto , Idoso , Algoritmos , Área Sob a Curva , Pressão Sanguínea/genética , Índice de Massa Corporal , Análise por Conglomerados , Estudos Transversais , Dislipidemias/diagnóstico , Dislipidemias/genética , Dislipidemias/metabolismo , Análise Fatorial , Feminino , Predisposição Genética para Doença , Inquéritos Epidemiológicos , Humanos , Hipertensão/diagnóstico , Hipertensão/genética , Hipertensão/fisiopatologia , Itália/epidemiologia , Metabolismo dos Lipídeos/genética , Masculino , Síndrome Metabólica/diagnóstico , Síndrome Metabólica/metabolismo , Síndrome Metabólica/fisiopatologia , Pessoa de Meia-Idade , Obesidade/diagnóstico , Obesidade/genética , Obesidade/fisiopatologia , Fenótipo , Valor Preditivo dos Testes , Prevalência , Curva ROC , Reprodutibilidade dos Testes , Fatores de Risco , Fatores Sexuais , Circunferência da Cintura
2.
Clin Exp Allergy ; 45(4): 797-806, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25431337

RESUMO

BACKGROUND: Exhaled nitric oxide (FeNO) is a biomarker for eosinophilic inflammation in the airways and for responsiveness to corticosteroids in asthmatics. OBJECTIVE: We sought to identify in adults the genetic determinants of fractional exhaled nitric oxide (FeNO) levels and to assess whether environmental and disease-related factors influence these associations. METHODS: We performed a genome-wide association study of FeNO through meta-analysis of two independent discovery samples of European ancestry: the outbred EGEA study (French Epidemiological study on the Genetics and Environment of Asthma, N = 610 adults) and the Hutterites (N = 601 adults), a founder population living on communal farms. Replication of main findings was assessed in adults from an isolated village in Sardinia (Talana study, N = 450). We then investigated the influence of asthma, atopy and tobacco smoke exposure on these genetic associations, and whether they were also associated with FeNO values in children of the EAGLE (EArly Genetics & Lifecourse Epidemiology, N = 8858) consortium. RESULTS: We detected a common variant in RAB27A (rs2444043) associated with FeNO that reached the genome-wide significant level (P = 1.6 × 10(-7) ) in the combined discovery and replication adult data sets. This SNP belongs to member of RAS oncogene family (RAB27A) and was associated with an expression quantitative trait locus for RAB27A in lymphoblastoid cell lines from asthmatics. A second suggestive locus (rs2194437, P = 8.9 × 10(-7) ) located nearby the sodium/calcium exchanger 1 (SLC8A1) was mainly detected in atopic subjects and influenced by inhaled corticosteroid use. These two loci were not associated with childhood FeNO values. CONCLUSIONS AND CLINICAL RELEVANCE: This study identified a common variant located in RAB27A gene influencing FeNO levels specifically in adults and with a biological relevance to the regulation of FeNO levels. This study provides new insight into the biological mechanisms underlying FeNO levels in adults.


Assuntos
Estudos de Associação Genética , Variação Genética , Óxido Nítrico , Proteínas rab de Ligação ao GTP/genética , Adulto , Alelos , Asma/genética , Asma/imunologia , Asma/metabolismo , Biomarcadores , Mapeamento Cromossômico , Expiração , Feminino , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Masculino , Metanálise como Assunto , Pessoa de Meia-Idade , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Fatores de Risco , Adulto Jovem , Proteínas rab27 de Ligação ao GTP
3.
Chem Senses ; 29(8): 697-702, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15466815

RESUMO

Recently, a major locus on chromosome 7q was found in association with the taste sensitivity to phenylthiocarbamide (PTC) in humans. This region contains the TAS2R38 gene that encodes a member of the TAS2R bitter taste receptor family. Three SNPs within this gene demonstrated a strong association with taster status in Utah families and in an additional sample of 85 unrelated individuals. We studied a small isolated village in eastern Sardinia and carried out a genome-wide scan to map the genetic basis of PTC perception in this population. We performed both qualitative and quantitative PTC-taste linkage analysis. Qualitative analysis was carried out by defining a cut-off from the bimodal distribution of the trait and classifying subjects as tasters and non-tasters (75 and 25%, respectively). Linkage analysis on 131 subjects belonging to a unique large multi-generation pedigree comprising 239 subjects confirmed significant evidence for linkage at 7q35 also in our population. Haplotype analyses of the three SNPs inside the PTC gene allowed us to identify only two haplotypes that were associated with the non-taster phenotype (80% AVI homozygous) and to taster phenotype (40% PAV homozygous and 56% PAV/AVI heterozygous). Sex, age and haplotype effect explained 77.2 % of the total variance in PTC sensitivity.


Assuntos
Feniltioureia/farmacologia , Receptores de Superfície Celular/genética , Paladar/genética , Paladar/fisiologia , Humanos , Itália , Receptores de Superfície Celular/fisiologia , Receptores Acoplados a Proteínas G
4.
Hum Mol Genet ; 13(1): 25-33, 2004 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-14613964

RESUMO

The extent of linkage disequilibrium (LD) is an important factor when designing experiments for mapping disease or trait loci using LD mapping methods. It depends on the population history and hence is a characteristic of each population. Here, we have assessed the extent of LD in a sub-isolate of the general Sardinian population (775 members of one village) using 22 polymorphic markers on chromosome 19. We found high levels of disequilibrium that extended to 8 cM, when based on D', and 11 cM when based on the significance level of the allelic association. The fact that conclusions based on both methods are similar suggests that the estimates are quite robust. We have also shown, through a simple resampling technique, that small sample sizes can overestimate both the mean value of D' and its variance up to a factor of about 2 and 16, respectively, when the number of diplotypes (the pair of haplotypes that compose the genotype) decreased from 186 to 26. We evaluated the effect on D' of the depth of the pedigree available when using phased founders, and compared the estimates with those obtained when using unphased founders, and also the effect of grouping alleles on the value of D' and the significance level. Owing to the high sampling variance of LD, we recommend the use of at least 200 unrelated individuals when characterizing the extent of LD.


Assuntos
Mapeamento Cromossômico/métodos , Cromossomos Humanos Par 19/genética , Genética Populacional , Desequilíbrio de Ligação/genética , Polimorfismo Genético , Alelos , Características da Família , Marcadores Genéticos , Haplótipos/genética , Humanos , Itália , Linhagem , Projetos de Pesquisa , Tamanho da Amostra
5.
Hum Genet ; 109(2): 198-209, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11511926

RESUMO

Genetic isolates represent exceptional resources for the mapping of complex traits but not all isolates are similar. We have selected a genetic and cultural isolate, the village of Talana from an isolated area of Sardinia, and propose that this population is suitable for the mapping of complex traits. A wealth of historical and archive data allowed the reconstruction of the demographic and genealogical history of the village. Key features of the population, which has grown slowly with no significant immigration, were defined by using a combination of historical, demographic and genetic studies. The genealogy of each Talana inhabitant was reconstructed and the main maternal and paternal lineages of the village were defined. Haplotype and phylogenetic analyses of the Y chromosome and characterisation of mitochondrial DNA haplogroups were used to determine the number of ancestral village founders. The extent of linkage disequilibrium (LD) was evaluated by the analysis of several microsatellites in chromosomal region Xq13.3, which was previously used to asses the extension of LD. Genealogical reconstructions were confirmed and reinforced by the genetic analyses, since some lineages were found to have merged prior to the beginning of the archival records, suggesting an even smaller number of founders than initially predicted. About 80% of the present-day population appears to derive from eight paternal and eleven maternal ancestral lineages. LD was found to span, on average, a 5-Mb region in Xq13.3. This suggests the possibility of identifying identical-by-descent regions associated with complex traits in a genome-wide search by using a low-density marker map. The present study emphasises the importance of combining genetic studies with genealogical and historical information.


Assuntos
Mapeamento Cromossômico/métodos , DNA Mitocondrial/genética , Modelos Genéticos , Característica Quantitativa Herdável , Cromossomo Y/genética , Feminino , Frequência do Gene , Marcadores Genéticos/genética , Variação Genética , Genética Populacional , Haplótipos , Humanos , Desequilíbrio de Ligação/genética , Masculino , Repetições de Microssatélites/genética , Linhagem , Cromossomo X/genética
6.
Am J Hum Genet ; 68(5): 1119-29, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11309680

RESUMO

Renal stone formation is a common multifactorial disorder, of unknown etiology, with an established genetic contribution. Lifetime risk for nephrolithiasis is approximately 10% in Western populations, and uric acid stones account for 5%-10% of all stones, depending on climatic, dietary, and ethnic differences. We studied a small, isolated founder population in Sardinia, characterized by an increased prevalence of uric acid stones, and performed a genomewide search in a deep-rooted pedigree comprising many members who formed uric acid renal stones. The pedigree was created by tracing common ancestors of affected individuals through a genealogical database based on archival records kept by the parish church since 1640. This genealogical information was used as the basis for the study strategy, involving screening for alleles shared among affected individuals, originating from common ancestors, and utilization of large pedigrees to obtain greater power for linkage detection. We performed multistep linkage and allele-sharing analyses. In the initial stage, 382 markers were typed in 14 closely related affected subjects; interesting regions were subsequently investigated in the whole sample. We identified two chromosomal regions that may harbor loci with susceptibility genes for uric acid stones. The strongest evidence was observed on 10q21-q22, where a LOD score of 3.07 was obtained for D10S1652 under an affected-only dominant model, and a LOD score of 3.90 was obtained using a dominant pseudomarker assignment. The localization was supported also by multipoint allele-sharing statistics and by haplotype analysis of familial cases and of unrelated affected subjects collected from the isolate. In the second region on 20q13.1-13.3, multipoint nonparametric scores yielded suggestive evidence in a approximately 20-cM region, and further analysis is needed to confirm and fine-map this putative locus. Replication studies are required to investigate the involvement of these regions in the genetic contribution to uric acid stone formation.


Assuntos
Ligação Genética/genética , Predisposição Genética para Doença/genética , Cálculos Renais/genética , Ácido Úrico/metabolismo , Alelos , Antropometria , Mapeamento Cromossômico , Cromossomos Humanos Par 10/genética , Cromossomos Humanos Par 20/genética , Dieta , Comportamento Alimentar , Feminino , Efeito Fundador , Haplótipos/genética , Heterozigoto , Humanos , Concentração de Íons de Hidrogênio , Itália/epidemiologia , Cálculos Renais/epidemiologia , Cálculos Renais/metabolismo , Cálculos Renais/urina , Escore Lod , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Linhagem , Prevalência , Software , Ácido Úrico/urina
7.
J Clin Oncol ; 19(5): 1437-43, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11230489

RESUMO

PURPOSE: Detection of occult metastasis before the development of clinical disease could allow more accurate staging, appropriate follow-up procedures, and adjuvant therapies in patients with malignant melanoma (MM). The sentinel lymph node (SLN) has been proposed as a reliable predictor of metastatic disease in the lymphatic basin draining the primary melanoma. In this study, we screened both paraffin-embedded SLNs and peripheral-blood (PB) samples from MM patients at various stage of disease using a multimarker reverse transcriptase polymerase chain reaction (RT-PCR) assay. The prognostic significance of the presence of PCR-positive markers was also evaluated. PATIENTS AND METHODS: Total RNA was obtained from paraffin-embedded SLN sections and PB samples of 75 MM patients. RT-PCR was performed using tyrosinase and MelanA/MART1 as melanoma-associated markers. Radiolabeled PCR products were analyzed on denaturing polyacrylamide gels. RESULTS: Good sensitivity of the RT-PCR assay on archival tissues was demonstrated after comparison of RT-PCR results on frozen and paraffin-embedded SLNs from 16 MM patients. Significant correlation between the disease stage and marker expression in both PB and SLN samples was observed; the highest value was for patients who were positive for both markers in SLN (P =.006). Progression of disease was significantly associated with the total number of PCR-positive markers in both PB (P =.034) and SLN (P =.001) samples. CONCLUSION: Although sensitivity is lowered by the use of paraffin-embedded specimens, our data indicate that RT-PCR analysis of serial sections from archival SLNs may be helpful in improving detection of occult micrometastases, thus improving staging of patients with melanoma.


Assuntos
Melanoma/diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , Biópsia de Linfonodo Sentinela , Neoplasias Cutâneas/diagnóstico , Biomarcadores Tumorais/análise , DNA de Neoplasias/análise , Reações Falso-Negativas , Humanos , Metástase Linfática/diagnóstico , Melanoma/patologia , Inclusão em Parafina , Prognóstico , Sensibilidade e Especificidade , Neoplasias Cutâneas/patologia , Manejo de Espécimes
8.
Recent Results Cancer Res ; 158: 200-3, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11092047

RESUMO

Reverse-transcriptase polymerase chain reaction (RT-PCR) with multiple markers has been demonstrated to be highly sensitive in detecting metastatic cells in peripheral blood of malignant melanoma (MM) patients, and the circulating MM cells to be significantly correlated with disease stages. We further evaluated the presence of specific PCR-positive mRNA markers in peripheral blood as well as in regional nodes as an expression of tumor progression. Peripheral blood samples from 317 MM patients with either localized (n = 219) or metastatic (n = 98) disease were processed to obtain total cellular RNA. RT-PCR was performed using tyrosinase (TYR), p97, and MelanA/MART1 as mRNA markers. PCR products were analyzed by gel electrophoresis and Southern blot hybridization. In addition, paraffin-embedded samples of histologically proven tumor-negative lymph nodes from the subset of patients with localized disease were analyzed by RT-PCR, using radiolabeled primers for TYR and MelanA/MART1. The presence of mRNA markers was significantly correlated with tumor burden with a good correlation between risk of recurrence (evaluated in stage I-III patients) and increasing number of PCR-positive markers (p = 0.0002). Currently, for each patient, PCR results obtained at different times during follow-up are being analyzed, and any variation in the number of PCR-positive markers is being correlated to the clinical status. Molecular screening of histologically negative nodes for the presence of metastatic MM cells is also under evaluation. Preliminary assessment of a subset of MM patients with higher risk of recurrence will require longer follow-up in order to define the role of RT-PCR in monitoring these patients.


Assuntos
Biomarcadores Tumorais/sangue , Linfonodos/patologia , Melanoma/sangue , Proteínas de Neoplasias/sangue , Células Neoplásicas Circulantes , RNA Mensageiro/análise , Neoplasias Cutâneas/sangue , Biomarcadores Tumorais/genética , Southern Blotting , Progressão da Doença , Seguimentos , Humanos , Proteínas de Neoplasias/genética , Estadiamento de Neoplasias , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
Br J Cancer ; 83(12): 1707-14, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11104570

RESUMO

Malignant melanoma (MM) is thought to arise by sequential accumulation of genetic alterations in normal melanocytes. Previous cytogenetic and molecular studies indicated the 9p21 as the chromosomal region involved in MM pathogenesis. In addition to the CDKN genes (p16/CDKN2A, p15/CDKN2B and p19(ARF), frequently inactivated in familial MM), widely reported data suggested the presence within this region of other melanoma susceptibility gene(s). To clearly assess the role of the 9p21 region in sporadic melanoma, we evaluated the presence of microsatellite instability (MSI) and loss of heterozygosity (LOH) in primary tumours as well as in synchronous or asynchronous metastases obtained from the same MM patients, using 9 polymorphic markers from a 17-cM region at 9p21. LOH and MSI were found in 27 (41%) and 11 (17%), respectively, out of 66 primary tumours analysed. In corresponding 58 metastases, MSI was found at higher rate (22; 38%), whereas a quite identical pattern of allelic deletions with 27 (47%) LOH+ cases were observed. Although the CDKN locus was mostly affected by LOH, an additional region of common allelic deletion corresponding to marker D9S171 was also identified. No significant statistical correlation between any 9p21 genetic alteration (LOH, MSI or both) and clinicopathological parameters was observed.


Assuntos
Cromossomos Humanos Par 9/genética , Melanoma/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , DNA de Neoplasias/genética , Feminino , Humanos , Perda de Heterozigosidade , Masculino , Melanoma/patologia , Repetições de Microssatélites , Pessoa de Meia-Idade , Metástase Neoplásica
10.
Cancer ; 89(8): 1773-82, 2000 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-11042573

RESUMO

BACKGROUND: Loss of heterozygosity (LOH) at chromosome 10q25-q26 has been reported previously in endometrial carcinoma (EC), suggesting the presence of tumor suppressor gene(s). Nevertheless, frequency of genome-wide microsatellite instability (MSI) has been demonstrated higher in EC than in other common malignancy, mostly due to defective DNA mismatch repair. The authors further evaluated the role of the chromosome 10q25-q26 in endometrial tumorigenesis as well as the clinical significance of any observed genetic alteration in sporadic EC. METHODS: Paired normal and tumor samples from 94 Sardinian patients with sporadic EC at various stages of disease were screened by polymerase chain reaction (PCR)-based microsatellite analysis. Genomic DNA was isolated from paraffin embedded tissues and amplified by PCR using microsatellite markers spanning approximately 14 cM at 10q25-q26. Microsatellite instability was studied at four loci mapping to different chromosomal locations. RESULTS: Thirty-two (34%) EC patients were found negative for genetic alterations within the 10q25-q26 region. Among the remaining 62 (66%) EC cases, the authors identified 1) a minimum consensus region of LOH of approximately 1 cM, between D10S610 and D10S542 markers; and 2) a subset of tumors with prevalence of instability at 10q25-q26 (10qMI+), as expression of the presence of a MSI+ phenotype. CONCLUSIONS: The authors' data establish the existence of significant correlations between disease stages and 10qMI+ (with or without MSI+). However, longer follow-up and additional studies are required to define the clinical significance of these findings as prognostic factors. Moreover, the minimum region of LOH at 10q25-q26 will be further analyzed for identifying the putative tumor suppressor gene involved in EC pathogenesis.


Assuntos
Cromossomos Humanos Par 10 , Neoplasias do Endométrio/genética , Perda de Heterozigosidade , Repetições de Microssatélites , Adulto , Idoso , Idoso de 80 Anos ou mais , Mapeamento Cromossômico , DNA de Neoplasias/genética , DNA de Neoplasias/isolamento & purificação , Neoplasias do Endométrio/patologia , Feminino , Marcadores Genéticos , Humanos , Itália , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Reação em Cadeia da Polimerase
11.
Arch Ophthalmol ; 118(5): 674-9, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10815160

RESUMO

BACKGROUND: Juvenile open-angle glaucoma has been found to be associated with molecular defects in the myocilin (MYOC) gene. Most of the defects are missense mutations located in the third exon. The Gln368stop mutation has recently been found in several cases of late-onset primary open-angle glaucoma (POAG). OBJECTIVE: To study the effect of glaucoma risk in a relatively homogeneous genetic population. METHODS: A clinical study was performed in all living members of a 5-generation family. DNA analysis was performed for studying association with genetic markers and identifying the mutation. RESULTS: We identified the Gln368stop molecular defect in 19 patients with POAG, 5 patients with ocular hypertension, and 22 healthy carriers. We compared affected and unaffected carriers based on age at onset and last examination, respectively. Besides the presence of 3 young patients with POAG (<40 years old), the number of glaucomatous patients in the advanced age group increased. CONCLUSIONS: The penetrance of glaucoma increases with age in Gln368stop carriers, but some remain unaffected at advanced age and others are affected at an early age. This suggests that additional risk factors are operating within this family, which may be identified by a genome-wide linkage search in this large pedigree. CLINICAL RELEVANCE: The myocilin Gln368stop mutation shows a good genotype-phenotype correlation and should be investigated in all familiar cases of chronic POAG. This may be important for early diagnosis and periodical checkups of presymptomatic individuals belonging to these families.


Assuntos
Códon de Terminação/genética , Proteínas do Olho/genética , Glaucoma de Ângulo Aberto/genética , Glicoproteínas/genética , Mutação , Fatores Etários , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Proteínas do Citoesqueleto , DNA/análise , Análise Mutacional de DNA , Sondas de DNA/química , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hipertensão Ocular/genética , Linhagem , Fatores de Risco
12.
Am J Ophthalmol ; 129(2): 260-2, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10682987

RESUMO

PURPOSE: To report the molecular characterization of a novel VMD2 mutation causing a Best macular dystrophy sporadic case. METHODS: All family members underwent ophthalmologic examination and genetic testing by single strand conformation polymorphism analysis and direct sequencing of the VMD2 gene. RESULTS: A single T to G transition at nucleotide 663 was identified in one of the VMD2 gene copies of the patient, which results in a Cys to Trp substitution at position 221 in the corresponding protein (C221W). Sequence analysis of the VMD2 exon 6 of both parents of the patient did not reveal any mutation. CONCLUSION: These data confirm the involvement of the VMD2 gene in Best macular dystrophy onset, even in sporadic cases of the disease, pointing out the relevance of molecular analysis in the diagnosis of this degenerative retinal disease.


Assuntos
Proteínas do Olho/genética , Degeneração Macular/genética , Mutação de Sentido Incorreto , Mutação Puntual , Substituição de Aminoácidos , Bestrofinas , Pré-Escolar , Canais de Cloreto , Feminino , Humanos , Degeneração Macular/patologia , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Análise de Sequência de DNA , Acuidade Visual
13.
Br J Cancer ; 82(3): 553-9, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10682665

RESUMO

Sardinian population can be instrumental in defining the molecular basis of cancer, using the identity-by-descent method. We selected seven Sardinian breast cancer families originating from the northern-central part of the island with multiple affected members in different generations. We genotyped 106 members of the seven families and 20 control nuclear families with markers flanking BRCA2 locus at 13q12-q13. The detection of a common haplotype shared by four out of seven families (60%) suggests the presence of a founder BRCA2 mutation. Direct sequencing of BRCA2 coding exons of patients carrying the shared haplotype, allowed the identification of a 'frame-shift' mutation at codon 2867 (8765delAG), causing a premature termination-codon. This mutation was found in breast cancer patients as well as one prostate and one bladder cancer patient with shared haplotype. We then investigated the frequency of 8765delAG in the Sardinian breast cancer population by analysing 270 paraffin-embedded normal tissue samples from breast cancer patients. Five patients (1.7%) were found to be positive for the 8765delAG mutation. Discovery of a founder mutation in Sardinia through the identity-by-descent method demonstrates that this approach can be applied successfully to find mutations either for breast cancer or for other types of tumours.


Assuntos
Neoplasias da Mama/genética , Efeito Fundador , Mutação , Proteínas de Neoplasias/genética , Fatores de Transcrição/genética , Proteína BRCA2 , Sequência de Bases , Primers do DNA , Feminino , Humanos , Masculino , Linhagem
14.
Nat Genet ; 23(4): 397-404, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10581024

RESUMO

The difficulty of identifying susceptibility genes for common diseases has polarized geneticists' views on what disease models are appropriate and how best to proceed once high-density genome maps become available. Different disease models have different implications for using linkage or linkage-disequilibrium-based approaches for mapping complex disease genes. We argue that the choice of study population is a critical factor when designing a study, and that genetically simplified isolates are more useful than diverse continental populations under most assumptions.


Assuntos
Mapeamento Cromossômico/métodos , Doenças Genéticas Inatas/genética , Alelos , Feminino , Ligação Genética , Variação Genética , Genética Populacional , Humanos , Desequilíbrio de Ligação , Masculino , Modelos Genéticos , Mutação , Fenótipo
15.
J Med Genet ; 36(11): 833-6, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10544227

RESUMO

In this study, we report further results of mutation analysis of the ATP7B gene in Wilson disease (WD) patients of Mediterranean origin. A total of 136 WD chromosomes, 73 of which were of Italian, 43 of Turkish, 18 of Sardinian, and two of Spanish origin, were analysed and the mutation characterised in 84.5% of them. We found 50 different mutations of which 19 are novel, including three nonsense, one frameshift, and 15 missense mutations. The mutations detected were rare and mostly found in the compound heterozygous state together with other mutations and only rarely in homozygosity. Most of these mutations lie in the transmembrane and ATP binding loop regions. These data expand our knowledge of both the structure-function relationships of the WD protein and the molecular pathology of WD, thus improving our capability of prevention and genetic counselling.


Assuntos
Adenosina Trifosfatases/genética , Proteínas de Transporte/genética , Proteínas de Transporte de Cátions , Degeneração Hepatolenticular/genética , Mutação , ATPases Transportadoras de Cobre , Análise Mutacional de DNA , Degeneração Hepatolenticular/epidemiologia , Heterozigoto , Humanos , Região do Mediterrâneo/epidemiologia
16.
Blood Cells Mol Dis ; 25(3-4): 193-209, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10575545

RESUMO

The promoter region of adult beta globin genes in humans and other mammals contains conserved regions of pivotal importance for their regulated tissue specific expression. These include the CACCC and CAAT motifs. The CACCC motif is duplicated in humans and other mammals. The human delta-globin gene lacks these conserved regions and its expression in normal individuals is about 3% that of the beta globin gene. Previous studies have shown that the introduction of the beta-globin CACCC or CAAT can activate the delta-globin gene promoter, but the effect of the distal CACCC element has not yet been tested. In the present study, using site-specific mutagenesis, we have introduced the consensus sequence for the distal and proximal CACCC motif and the CAAT box alone or in combination in the wild-type delta-globin gene promoter. The resulting mutants, as well as the wild type (wt) delta- and beta-globin gene promoters, have been analyzed in a transient expression assay in Cos7, K562, and MEL cell lines. The results show that the CACCC boxes can increase the transcription efficiency of the delta-globin gene promoter in both erythroid and non-erythroid cell systems. The contribution of the two CACCC elements is almost equal in the non-erythroid (Cos7) and erythroid embryonic-fetal cell lines (K562), while the proximal CACCC element is more active in adult erythroid cells (MEL). Nonetheless, duplication of this element does not appear to affect the efficiency of the promoter synergistically. Furthermore, to assess the competitive ability of the delta globin promoter containing the proximal or distal CACCC consensus sequences over the wt beta globin gene promoter, we have carried out transient expression experiments using DNA constructs in which the delta and beta globin gene promoters are linked in cis and are sharing a single enhancer (competitive transient expression). The results show that both CACCC elements are able to activate the delta globin gene promoter in Cos7 and K562 cells, although to a different extent, whereas only the proximal CACCC element is effective in increasing the transcription efficiency in MEL cells. These findings are in agreement with the more severe clinical phenotype produced by the beta-thalassemia mutations affecting the proximal CACCC box as compared with those within the distal CACCC box. The Erythroid Kruppel Like Factor (EKLF) is a nuclear protein restricted to erythroid cells which specifically bind the CACCC box sequence and activate the beta-globin gene. In the present study we carried out transactivation experiments of the mutagenized delta-globin gene promoter by introducing an EKLF expressing construct in erythroid cells. Constructs containing the proximal but not those bearing the distal CACCC element are transactivated. Our results indicate that the proximal CACCC box and, to a lesser extent, also the distal box have a role in the regulated stage specific expression of a beta-like globin gene, and show that the insertion of a single CACCC motif in the delta-globin gene promoter is sufficient to increase its activity. Nevertheless only the delta globin gene promoter containing the proximal CACCC element is able to compete with the wt beta globin gene promoter in the adult erythroid environment. These findings have potential relevance for the future prospective treatment of inherited hemoglobinopathies based on the conversion of the low functioning delta-globin gene into a high functioning beta-like globin gene.


Assuntos
Globinas/genética , Animais , Sequência de Bases/genética , Células COS , Proteínas de Ligação a DNA/genética , Expressão Gênica , Regulação da Expressão Gênica , Humanos , Células K562 , Fatores de Transcrição Kruppel-Like , Camundongos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Regiões Promotoras Genéticas/genética , RNA Mensageiro/análise , Fatores de Transcrição/genética , Ativação Transcricional , Transfecção , Células Tumorais Cultivadas
17.
Hum Mutat ; 14(4): 294-303, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10502776

RESUMO

Wilson disease (WD) in the Sardinian population has an approximate incidence of 1:7,000 live births. Mutation analysis of the WD gene in this population reported in our previous articles led us to the characterization of two common mutations and a group of 13 rare mutations accounting for the molecular defect of 8.5, 7.9, and 15.1% of the WD chromosomes. However, molecular analysis of the WD chromosomes containing the most common haplotype, which accounts for 60.5% of the WD chromosomes, failed to define the disease-causing mutation. In this study, we characterized the promoter and the 5' UTR of the WD gene sequence and carried out a mutation analysis in this DNA region from patients with the most common haplotype. The promoter is contained in a GC-rich island and shows a TATA and a CAAT consensus sequence as well as potential binding sites for transcription factors and metal response elements. In all the analyzed 92 chromosomes with this haplotype, we detected a single mutation consisting of a 15-nt deletion from position -441 to position -427 relative to the translation start site. Expression assays demonstrated a 75% reduction in the transcriptional activity of the mutated sequence compared to the normal control. By adding this mutation to those that have been already characterized, we have now defined the molecular defect in 92% of the WD chromosomes in Sardinians. The high frequency, the expected prevention by preclinical diagnosis and early treatment of the devastating effect of WD on the nervous system and liver tissue, and the feasibility to detect most of molecular defects by DNA analysis indicate that WD in the Sardinian population should be added to the list of diseases currently detected by newborn screening.


Assuntos
Efeito Fundador , Degeneração Hepatolenticular/genética , Mutação , Regiões 5' não Traduzidas/genética , Sequência de Bases , Sítios de Ligação , Mapeamento Cromossômico , Sequência Consenso , DNA/sangue , DNA/genética , Éxons , Haplótipos , Degeneração Hepatolenticular/epidemiologia , Humanos , Incidência , Itália/epidemiologia , Fígado/metabolismo , Dados de Sequência Molecular , Mutação Puntual , Regiões Promotoras Genéticas , Deleção de Sequência , Fatores de Transcrição/metabolismo
18.
Eur J Hum Genet ; 7(5): 574-8, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10439964

RESUMO

X-linked congenital stationary night blindness (CSNBX) is a hereditary non-progressive retinal disorder, which can appear in two different clinical forms, complete and incomplete, associated with CSNB1 and CSNB2 loci on Xp. We describe a Sardinian family with complete CSNBX and define better the limits of the CSNB1 genetic locus on Xp11.4 through linkage analysis. Haplotype analysis showed two key recombinants, which restrict the CSNB1 locus to a region of about 3 cM limited by markers DSX1068 and DSX6810 respectively. The locus that we describe is included in the CSNB1 locus defined by previous reports referring to the same clinical form of the disease. These results, in addition to other recent mapping reports about families from different geographical areas, confirm the genetic homogeneity of X-linked complete CSNB.


Assuntos
Cegueira Noturna/congênito , Cegueira Noturna/genética , Cromossomo X , Mapeamento Cromossômico , Haplótipos , Humanos , Itália , Escore Lod
19.
Am J Med Genet ; 85(2): 175-8, 1999 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-10406672

RESUMO

We have studied a patient with Wilson disease (WD), belonging to a family segregating late-onset, dominant cerebellar ataxia. Analysis of the WD gene showed that the patient is a compound heterozygote, carrying the 14His1069Gln mutation from the father and the 8Gly710Ser mutation from the mother. The 8Gly710Ser is a mutation described previously only in a Swedish patient. Our patient is also homozygous for arylsulfatase A pseudodeficiency. This genetic defect, which has been reported in association with other neuropsychiatric syndromes, has not been described in WD.


Assuntos
Cerebrosídeo Sulfatase/deficiência , Degeneração Hepatolenticular/genética , Mutação , Adulto , Encéfalo/diagnóstico por imagem , Ataxia Cerebelar/genética , Cerebrosídeo Sulfatase/sangue , Cobre/sangue , Degeneração Hepatolenticular/sangue , Humanos , Masculino , Polimorfismo Conformacional de Fita Simples , Tomografia Computadorizada de Emissão de Fóton Único
20.
Cancer Genet Cytogenet ; 107(1): 37-42, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9809032

RESUMO

Retrospective analysis of chromosomal changes in endometrial carcinoma was performed by fluorescence in situ hybridization on free nuclei isolated from formalin-fixed paraffin-embedded tissue. We examined 23 archival samples for numerical aberrations of chromosomes 1 and 10 with the use of specific DNA probes for the pericentromeric and centromeric regions of these two chromosomes. Numerical aberrations of chromosomes 1 and 10 were detected in 39% of the case analyzed, and the frequency of trisomy 10 tended to increase as the histological grade worsened. Our findings confirm the association of cytogenetic anomalies involving chromosomes 1 and 10 with endometrial carcinoma, as reported by other studies, and suggest that changes in centromere 10 copy number may correlate with the degree of tumor differentiation.


Assuntos
Aneuploidia , Carcinoma Adenoescamoso/genética , Carcinoma Endometrioide/genética , Cromossomos Humanos Par 10/genética , Cromossomos Humanos Par 1/genética , Neoplasias do Endométrio/genética , Adulto , Idoso , Feminino , Marcadores Genéticos , Humanos , Hibridização in Situ Fluorescente , Pessoa de Meia-Idade , Inclusão em Parafina , Estudos Retrospectivos
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