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1.
Clin Genet ; 70(1): 34-8, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16813601

RESUMO

Mutations in the EIF2AK3 gene have been identified in patients with Wolcott-Rallison syndrome - a rare autosomal recessive disorder associated with permanent neonatal insulin-dependent diabetes. Despite the fact that different mutations have been observed in every single unrelated case reported so far, most patients presented with similar characteristics, such as osteopenia, epiphyseal dysplasia as well as hepatic and/or renal dysfunction. The EIF2AK3 gene was analyzed using a PCR-based sequencing approach in two Wolcott-Rallison patients and their parents. We report two cases from different families carrying the same and novel truncating nonsense mutation in the EIF2AK3 gene that encodes the pancreatic eukaryotic initiation factor 2alpha kinase 3. This mutation clearly displays different clinical characteristics in the two patients we examined. Remarkably, the onset of diabetes was different for the two patients, and there was also heterogeneity in other clinical manifestations. These cases illustrate the important role of alternative pathways that could, to some extent, take over or supplement a defective metabolic pathway. This supports the idea that there is no simple relationship among clinical manifestations and EIF2AK3 mutations.


Assuntos
Códon sem Sentido , Diabetes Mellitus Tipo 1/enzimologia , Diabetes Mellitus Tipo 1/genética , Osteocondrodisplasias/enzimologia , Osteocondrodisplasias/genética , eIF-2 Quinase/genética , Sequência de Aminoácidos , Sequência de Bases , Criança , Pré-Escolar , DNA/genética , Éxons , Feminino , Genes Recessivos , Transtornos do Crescimento/enzimologia , Transtornos do Crescimento/genética , Humanos , Recém-Nascido , Masculino , Fenótipo , Síndrome
2.
Br J Cancer ; 90(10): 2002-5, 2004 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-15138485

RESUMO

Variation in the penetrance estimates for BRCA1 and BRCA2 mutation carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. The RAD51 gene, which participates in homologous recombination double-strand breaks (DSB) repair in the same pathway as the BRCA1 and BRCA2 gene products, is a candidate for such an effect. A single-nucleotide polymorphism (SNP), RAD51-135g-->c, in the 5' untranslated region of the gene has been found to elevate breast cancer (BC) risk among BRCA2 carriers. We genotyped 309 BRCA1/2 mutation carriers, of which 280 were of Ashkenazi origin, 166 noncarrier BC patients and 152 women unaffected with BC (a control group), for the RAD51-135g-->c SNP. Risk analyses were conducted using COX proportional hazard models for the BRCA1/2 carriers and simple logistic regression analysis for the noncarrier case-control population. BRCA2 carriers were also studied using logistic regression and Kaplan-Meier survival analyses. The estimated BC hazard ratio (HR) for RAD51-135c carriers adjusted for origin (Ashkenazi vs non-Ashkenazi) was 1.28 (95% CI 0.85-1.90, P=0.23) for BRCA1/2 carriers, and 2.09 (95% CI 1.04-4.18, P=0.04) when the analysis was restricted to BRCA2 carriers. The median BC age was younger in BCRA2-RAD51-135c carriers (45 (95% CI 36-54) vs 52 years (95% CI 48-56), P=0.05). In a logistic regression analysis, the odds ratio (OR) was 5.49 (95% CI 0.5-58.8, P=0.163). In noncarrier BC cases, carrying RAD51-135c was not associated with BC risk (0.97; 95% CI 0.47-2.00). These results indicate significantly elevated risk for BC in carriers of BRCA2 mutations who also carry a RAD51-135c allele. In BRCA1 carriers and noncarriers, no effect for this SNP was found.


Assuntos
Neoplasias da Mama/genética , Proteínas de Ligação a DNA/genética , Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Adulto , Idade de Início , Estudos de Casos e Controles , Dano ao DNA , Reparo do DNA , Feminino , Genótipo , Humanos , Judeus/genética , Pessoa de Meia-Idade , Razão de Chances , Reação em Cadeia da Polimerase , Rad51 Recombinase , Análise de Sobrevida
3.
BJU Int ; 92(1): 109-12, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12823393

RESUMO

OBJECTIVE: To report a case-control study examining the relationship between polymorphisms in the leptin receptor (OBR) gene and the development of young-onset prostate cancer, because epidemiological studies report that prostate cancer risk is associated with animal fat intake, and thus we investigated if this association occurs via this genetic mechanism. PATIENTS, SUBJECTS AND METHODS: The Lys109Arg (OBR1) and Gln223Arg (OBR2) polymorphisms in the coding region of OBR were studied in blood DNA from 271 patients with prostate cancer aged < 56 years at diagnosis and 277 geographically matched control subjects. Cases were collected through the Cancer Research UK/British Prostate Group Familial Prostate Cancer Study. Blood DNA was genotyped using the polymerase chain reaction and a restriction enzyme digest. RESULTS: There was no statistically significant association between the OBR genotype and prostate cancer risk; men homozygous for 109Arg genotype had a slightly increased risk for prostate cancer, with a relative risk (95% confidence interval) of 1.36 (0.65-2.85), and those homozygous for the 223Arg allele had some reduction in prostate cancer risk, at 0.82 (0.58-1.26), but neither was statistically significant. CONCLUSION: This case-control study showed no significant association between leptin receptor gene polymorphisms and the risk of young-onset prostate cancer, suggesting that genetic variations in OBR are unlikely to have a major role in the development of early-onset prostate cancer in the UK.


Assuntos
Proteínas de Transporte/genética , Polimorfismo Genético/genética , Neoplasias da Próstata/genética , Adulto , Idade de Início , Estudos de Casos e Controles , Genótipo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Pessoa de Meia-Idade , Fatores de Risco
4.
Prostate Cancer Prostatic Dis ; 5(3): 189-92, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12496980

RESUMO

Epidemiological studies have suggested an association between low selenium levels and the development of prostate cancer. Human cellular glutathione peroxidase I (hGPX1) is a selenium-dependent enzyme that protects against oxidative damage and its peroxidase activity is a plausible mechanism for cancer prevention by selenium. The GPX1 gene has a GCG repeat polymorphism in exon 1, coding for a polyalanine tract of five to seven alanine residues. To test if the GPX1 GCG repeat polymorphism associates with the risk of young-onset prostate cancer we conducted a case-control study. The GPX1Ala genotypes were determined for 267 prostate cancer cases and 260 control individuals using polymerase chain reaction (PCR) amplification with fluorescently labelled primers and an ABI 377 automated genotyper. Associations between specific genotypes and the risk of prostate cancer were examined by logistic regression. We found no significant association between the GPX1 genotypes and prostate cancer. There was however an increased frequency of the GPX1Ala6/Ala6 genotype in the prostate cancer cases compared to controls (OR: 1.67; 95% CI: 0.97-2.87). The result of this study suggests that the GPX1 genotype is unlikely to be associated with the risk of developing prostate cancer.


Assuntos
Glutationa Peroxidase/genética , Neoplasias da Próstata/genética , Selênio/farmacologia , Repetições de Trinucleotídeos , Adulto , Alelos , Genes p53/fisiologia , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Neoplasias da Próstata/enzimologia , Fatores de Risco
5.
Ann Hum Genet ; 66(Pt 3): 223-33, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12174213

RESUMO

The design of association studies is critically dependent upon the extent of linkage disequilibrium (LD) across different genomic regions, often summarised in terms of the mean absolute value of summary linkage disequilibrium measures. The two most commonly used measures are D' for estimating the magnitude or extent of LD, and Delta which is directly proportional to the power of LD mapping. We studied the sampling distribution of the mean of /D'/ and /Delta/ statistics for varying sample size and major allele frequencies. When the sample size is small or one allele frequency is extreme, estimates of the magnitude of association based on the mean of /D'/ can be substantially inflated. This inflation is more marked when the haplotype frequencies have been inferred from genotype counts. The net effect of this means that smaller studies will tend to show higher levels of LD. The magnitude of this inflation can be reduced by use of a bootstrap correction, and by avoiding using markers with extreme allele frequencies. In contrast, the /Delta/ statistic is much less affected by sample size and high major allele frequencies. These effects are illustrated with real data on 36 SNPs typed in an Ashkenasi Jewish population.


Assuntos
Desequilíbrio de Ligação , Projetos de Pesquisa , Humanos , Estudos de Amostragem , Viés de Seleção
6.
Pharmacogenetics ; 11(4): 325-30, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11434510

RESUMO

There is evidence suggesting that polymorphic variations in the glutathione S-transferases (GSTs) are associated with cancer susceptibility. Inter-individual differences in cancer susceptibility may be mediated in part through polymorphic variability in the bioactivation and detoxification of carcinogens. The GSTs have been consistently implicated as cancer susceptibility genes in this context. The GST supergene family includes several loci with well characterized polymorphisms. Approximately 50% of the Caucasian population are homozygous for deletions in GSTM1 and approximately 20% are homozygous for deletions in GSTT1, resulting in conjugation deficiency of mutagenic electrophiles to glutathione. The GSTP1 gene has a polymorphism at codon 105 resulting in an Ile to Val substitution which consequently alters the enzymatic activity of the protein and this has been suggested as a putative high-risk genotype in various cancers. We investigated the relationship between GST polymorphisms and young onset prostate cancer in a case-control study. GSTM1, GSTT1 and GSTP1 genotypes were determined for 275 prostate cancer patients and for 280 geographically matched control subjects. We found no significant difference in the frequency of GSTM1 or GSTT1 null genotypes between cases and controls. GSTP1 genotype was, however, significantly associated with prostate cancer risk: the Ile/Ile homozygotes had the lowest risk and there was a trend in increasing the risk with the number of 105 Val alleles: Ile/Val odds ratio (OR)= 1.30 (95% FCI 0.99-1.69), Val/Val OR = 1.80 (95% FCI 1.11-2.91); Ptrend = 0.026. These results suggest that the GSTP1 polymorphism may be a risk factor for developing young onset prostate cancer. We also found that carrying more than one putative high-risk allele in the carcinogen metabolizing GST family was associated with an elevated risk for early onset prostate cancer (OR 2.48, 95% FCI 1.22-5.04, Ptrend = 0.017).


Assuntos
Glutationa Transferase/genética , Isoenzimas/genética , Polimorfismo Genético , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/genética , Adulto , Idade de Início , Alelos , Substituição de Aminoácidos , Sequência de Bases , Estudos de Casos e Controles , Primers do DNA/genética , Genótipo , Glutationa S-Transferase pi , Glutationa Transferase/deficiência , Homozigoto , Humanos , Isoenzimas/deficiência , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Deleção de Sequência
7.
Br J Cancer ; 85(1): 36-40, 2001 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-11437399

RESUMO

Variation in the penetrance estimates for BRCA1 and BRCA2 mutations carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. A previous study has suggested that BRCA1 carriers with longer lengths of the CAG repeat in the androgen receptor (AR) gene are at increased risk of breast cancer (BC). We genotyped 188 BRCA1/2 carriers (122 affected and 66 unaffected with breast cancer), 158 of them of Ashkenazi origin, 166 BC cases without BRCA1/2 mutations and 156 Ashkenazi control individuals aged over 56 for the AR CAG and GGC repeats. In carriers, risk analyses were conducted using a variant of the log-rank test, assuming two sets of risk estimates in carriers: penetrance estimates based on the Breast Cancer Linkage Consortium (BCLC) studies of multiple case families, and lower estimates as suggested by population-based studies. We found no association of the CAG and GGC repeats with BC risk in either BRCA1/2 carriers or in the general population. Assuming BRCA1/2 penetrance estimates appropriate to the Ashkenazi population, the estimated RR per repeat adjusted for ethnic group (Ashkenazi and non-Ashkenazi) was 1.05 (95%CI 0.97-1.17) for BC and 1.00 (95%CI 0.83-1.20) for ovarian cancer (OC) for CAG repeats and 0.96 (95%CI 0.80-1.15) and 0.90 (95%CI 0.60-1.22) respectively for GGC repeats. The corresponding RR estimates for the unselected case-control series were 1.00 (95%CI 0.91-1.10) for the CAG and 1.05 (95%CI 0.90-1.22) for the GGC repeats. The estimated relative risk of BC in carriers associated with > or =28 CAG repeats was 1.08 (95%CI 0.45-2.61). Furthermore, no significant association was found if attention was restricted to the Ashkenazi carriers, or only to BRCA1 or BRCA2 carriers. We conclude that, in contrast to previous observations, if there is any effect of the AR repeat length on BRCA1 penetrance, it is likely to be weak.


Assuntos
Neoplasias da Mama/genética , Genes BRCA1/genética , Proteínas de Neoplasias/genética , Polimorfismo Genético/genética , Receptores Androgênicos/genética , Fatores de Transcrição/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Proteína BRCA2 , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa , Heterozigoto , Humanos , Judeus/genética , Pessoa de Meia-Idade , Penetrância , Sequências Repetitivas de Ácido Nucleico
8.
Am J Hum Genet ; 67(6): 1544-54, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11078480

RESUMO

The design and feasibility of whole-genome-association studies are critically dependent on the extent of linkage disequilibrium (LD) between markers. Although there has been extensive theoretical discussion of this, few empirical data exist. The authors have determined the extent of LD among 38 biallelic markers with minor allele frequencies >.1, since these are most comparable to the common disease-susceptibility polymorphisms that association studies aim to detect. The markers come from three chromosomal regions-1,335 kb on chromosome 13q12-13, 380 kb on chromosome 19q13.2, and 120 kb on chromosome 22q13.3-which have been extensively mapped. These markers were examined in approximately 1,600 individuals from four populations, all of European origin but with different demographic histories; Afrikaners, Ashkenazim, Finns, and East Anglian British. There are few differences, either in allele frequencies or in LD, among the populations studied. A similar inverse relationship was found between LD and distance in each genomic region and in each population. Mean D' is.68 for marker pairs <5 kb apart and is.24 for pairs separated by 10-20 kb, and the level of LD is not different from that seen in unlinked marker pairs separated by >500 kb. However, only 50% of marker pairs at distances <5 kb display sufficient LD (delta>.3) to be useful in association studies. Results of the present study, if representative of the whole genome, suggest that a whole-genome scan searching for common disease-susceptibility alleles would require markers spaced < or = 5 kb apart.


Assuntos
Mapeamento Cromossômico , Predisposição Genética para Doença/genética , Desequilíbrio de Ligação/genética , Filogenia , África/etnologia , Alelos , Mapeamento Cromossômico/métodos , Cromossomos Humanos Par 13/genética , Cromossomos Humanos Par 19/genética , Cromossomos Humanos Par 22/genética , Demografia , Finlândia/etnologia , Frequência do Gene/genética , Marcadores Genéticos/genética , Genótipo , Humanos , Judeus/genética , Polimorfismo Genético/genética , Reino Unido/etnologia
9.
Carcinogenesis ; 21(2): 189-93, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10657957

RESUMO

The aromatase enzyme catalyses the conversion of androgens to oestrogens in the oestrogen biosynthesis pathway. Because increased exposure to oestrogens is considered to be a risk factor for breast cancer, the human aromatase gene (CYP19) is a plausible candidate for low penetrance breast cancer susceptibility. Preliminary reports have suggested that specific alleles of a TTTA repeat may be associated with differences in breast cancer risk. We have identified two new polymorphisms in the CYP19 gene: a TCT insertion/deletion in intron 4 and a G-->T substitution in intron 6, which have rare allele frequencies of 0.35 and 0.45, respectively, in the British population. Comparison was made between the frequencies of these alleles and those of the TTTA repeat in up to 599 breast cancer cases and 433 normal controls from the East Anglian, British population. We found strong linkage disequilibrium between the alleles of these three loci, but no significant association of any alleles with breast cancer risk. The maximum odds ratios observed were: 1.03 (95% CI 0.68-1.55) for the intron 4 TCT insertion/deletion polymorphism [del/del versus ins/ins]; 1.56 (95% CI 0.63-3.83) for the intron 4 [TTTA](10) allele; 1.29 (95% CI 0. 75-2.21) for the intron 6 G-->T polymorphism [TT versus GG]. We conclude that the CYP19 gene has no major role in common breast cancer incidence in the British population.


Assuntos
Aromatase/genética , Neoplasias da Mama/genética , Polimorfismo Genético , Adulto , Idoso , Alelos , Substituição de Aminoácidos , Aromatase/fisiologia , Neoplasias da Mama/enzimologia , Neoplasias da Mama/epidemiologia , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Hormônios Esteroides Gonadais/metabolismo , Humanos , Íntrons/genética , Desequilíbrio de Ligação , Pessoa de Meia-Idade , Razão de Chances , Mutação Puntual , Risco , Reino Unido/epidemiologia
10.
Prostate Cancer Prostatic Dis ; 3(4): 241-247, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12497071

RESUMO

There is evidence for genetic predisposition to prostate cancer. However, prostate cancer genes have been more difficult to find than genes for some of the other common cancers, such as breast and colon cancer. The reasons for this are discussed in this article and it is now becoming clear that prostate cancer is probably due to multiple genes, many of which are moderate or low penetrance. The advances in the Human Genome Project and technology, especially that of robotics, will help to overcome these problems. Prostate Cancer and Prostatic Diseases (2000) 3, 241-247

11.
Carcinogenesis ; 20(11): 2131-5, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10545416

RESUMO

Endogenous hormone exposure is known to alter breast cancer susceptibility and genes responsive to such hormones are plausible candidates for predisposition genes. We have examined polymorphisms in genes for two members of the nuclear receptor superfamily which are expressed in breast tissue and known to moderate rates of cell proliferation in a case-control association study: the androgen receptor (AR) and the vitamin D receptor (VDR). We have used two series of Caucasian female breast cancer cases, one incident and one prevalent, and compared both with two sets of matched controls from the East Anglian region of Britain. Since the results are similar in the two series we have combined them. The AR poly[Gly](n) and poly[Gln](n) tracts were genotyped in a total of 508 female breast cancer cases and 426 controls. The VDR TaqI polymorphism was analysed in 951 cases and 627 controls drawn from the same population series. There were no significant differences between cases and controls for either the AR or VDR polymorphisms. Compared with individuals with two short alleles (<22 repeats) of the AR poly[Gln](n) tract, the odds ratios and 95% confidence intervals (95% CI) for individuals with one or two long alleles were 0.82 (95% CI 0.62-1.09) and 1.31 (95% CI 0.87-1.97), respectively. Heterozygotes and homozygotes for the VDR TaqI cutting site had odds ratios of 1.01 (95% CI 0.81-1.27) and 0.97 (95% CI 0.71-1.32), respectively. None of the AR or VDR polymorphisms investigated has a major effect on risk of breast cancer in the British population.


Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença , Polimorfismo Genético , Receptores Androgênicos/genética , Receptores de Calcitriol/genética , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade
13.
Am J Hum Genet ; 62(3): 653-8, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9497242

RESUMO

Prostate cancer shows evidence of familial aggregation, particularly at young ages at diagnosis, but the inherited basis of familial prostate cancer is poorly understood. Smith et al. recently found evidence of linkage to markers on 1q, at a locus designated "HPC1," in 91 families with multiple cases of early-onset prostate cancer. Using both parametric and nonparametric methods, we attempted to confirm this finding, in 60 affected related pairs and in 76 families with three or more cases of prostate cancer, but we found no significant evidence of linkage. The estimated proportion of linked families, under a standard autosomal dominant model, was 4%, with an upper 95% confidence limit of 31%. We conclude that the HPC1 locus is responsible for only a minority of familial prostate cancer cases and that it is likely to be most important in families with at least four cases of the disease.


Assuntos
Cromossomos Humanos Par 1 , Ligação Genética , Marcadores Genéticos , Neoplasias da Próstata/genética , Heterogeneidade Genética , Predisposição Genética para Doença , Humanos , Escore Lod , Masculino
14.
Pharmacogenetics ; 8(1): 49-53, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9511181

RESUMO

The first rate-limiting step in the biosynthesis of all mammalian steroid hormones is the conversion of cholesterol to pregnenolone by the cholesterol side-chain cleavage enzyme, P450scc. The human CYP11A1 gene, encoding the mitochondrial P450scc, has been previously assigned by in situ hybridization to 15q23-q24 region. To map the CYP11A1 gene with linkage analysis, a novel TAAAA repeat polymorphism, found in its promoter region, was genotyped in the eight largest CEPH reference families, which included 91 children, 16 parents and 26 grandparents. Two-point linkage analysis was performed between this tetra-allelic polymorphism and the chromosome 15 microsatellite markers of Généthon as well as the tetranucleotide polymorphism of the CYP19 gene and a MspI RFLP of the CYP1A1 gene. A close linkage was observed with D15S204 (Z max = 27.33; theta max = 0.009) and CYP1A1 gene (Z max = 6.62; theta max = 0.001), but not with the CYP19 gene (Z max = 4.06; theta max = 0.26). The CYP19 gene that encodes the P450arom was rather closely linked with D15S123 (Z max = 31.04; theta max = 0.001). A framework map, including Généthon markers flanking the polymorphic CYP11A1 and CYP19 genes, was built by multipoint linkage analysis. Thereafter, a high-resolution genetic map of the 15q15-q25.3 region was constructed, yielding to the following order: cen-D15S214-[D15S123; CYP19]-D15S117-D15S159-D15S153-D15S983-[++ +D15S204; CYP11A1; CYP1A1]-D15S211-D15S152-D15S199-tel. Thus, the CYP11A1 gene is closely linked with the CYP1A1 gene, whereas it is located approximately 27.4 cM telomeric to the CYP19 gene.


Assuntos
Enzima de Clivagem da Cadeia Lateral do Colesterol/genética , Mapeamento Cromossômico , Cromossomos Humanos Par 15/genética , Citocromo P-450 CYP1A1/genética , Ligação Genética , Alelos , Sequência de Bases , Primers do DNA/genética , Feminino , Genótipo , Humanos , Masculino , Repetições de Microssatélites , Razão de Chances , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição
15.
J Histochem Cytochem ; 45(9): 1173-88, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9283605

RESUMO

The breast and ovarian cancer susceptibility gene BRCA1 encodes a phosphoprotein of 1863 amino acids containing a highly conserved N-terminal RING finger domain and a C-terminal acidic region typical of several transcription factors. BRCA1 acts as a tumor suppressor that may inhibit the proliferation of breast and ovarian cancer cells. To gain knowledge and to further understand the biological function of BRCA1, we examined its localization and expression in various tissues from 20-year-old male and female cynomolgus monkeys (Macaca fascicularis) by in situ hybridization using a 35S-labeled human BRCA1 DNA probe fragment derived from exon 11. In mammary glands, BRCA1 expression was primarily located in the duct and acinar epithelial cells. In the ovary, strong BRCA1 expression was detected in granulosa cells in maturing follicles and in luteal cells of the corpus luteum, as well as in the epithelial cells overlying the tunica albuginea. Specific signal was also observed in epithelial cells of the oviduct, endometrium, cervix, and vagina. Moreover, BRCA1 was strongly expressed in the germinal epithelium of the seminiferous tubules as well as over interstitial cells of the testis, in the epithelium of the epididymis, and in epithelial cells bordering the glandular lumen of the seminal vesicles. Signal was also detected in both the anterior and posterior lobes of the pituitary. In the adrenal glands, the signal was greater in the zona glomerulosa compared to the two other cortical zones, whereas the medullary cells were weakly labeled. In the stomach, and in small and large intestine, epithelial cells of the crypts usually exhibited stronger positive reaction than that observed over surface epithelial lining cells. BRCA1 expression was also found in diverse types of epithelial cells of the thyroid, pancreas, salivary glands, trachea, urinary bladder, and kidneys. In addition to demonstrating widespread tissue- and cell-specific expression of the BRCA1 gene in primate tissues, primarily in the epithelia, we observed a weaker but specific signal in various other cell types, suggesting a generalized biological function of BRCA1.


Assuntos
Genes BRCA1/genética , Animais , Mama/metabolismo , Sistema Digestório/metabolismo , Glândulas Endócrinas/metabolismo , Feminino , Genitália Feminina/metabolismo , Genitália Masculina/metabolismo , Humanos , Hibridização In Situ , Macaca fascicularis , Masculino , Glândulas Mamárias Animais/metabolismo , Dados de Sequência Molecular , Miocárdio/metabolismo , RNA Mensageiro/análise , Pele/metabolismo , Distribuição Tecidual , Traqueia/metabolismo , Sistema Urinário/metabolismo
16.
J Med Genet ; 33(10): 814-9, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8933332

RESUMO

Germline mutations in the BRCA1 tumour suppressor gene on chromosome 17q21 are responsible for approximately half of the cases of hereditary breast cancer, including the majority of familial breast/ovarian cancers. To increase our knowledge of the spectrum of BRCA1 mutations, we have extended our analysis to include patients with varied family histories of cancer of the breast, ovary, and at multiple other sites. We have analysed 23 unrelated familial cases using direct sequencing or a combination of dideoxy fingerprinting and sequencing procedures. Twenty one of these families contained three or more cases of breast or ovarian cancer and two families had one case of breast cancer diagnosed before the age of 40 and one case of ovarian cancer. The common frameshift mutation 5382insC was detected in two patients, and the 185delAG mutation was found in a family of Ashkenazi Jewish descent. The novel frameshift mutation 3450del4 (CAAG) was detected in a patient who developed breast cancer at the age of 28 and ovarian cancer at the age of 34. Three other women in this family were diagnosed with breast cancer at the ages of 26, 29, and 40. The novel framshift mutation 2953del3+C was found in a French Canadian woman who had developed two primary cancers of the breast at the age of 37 and 38 and renal cancer at the age of 38.


Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , DNA de Neoplasias , Neoplasias Primárias Múltiplas/genética , Neoplasias Ovarianas/genética , Adulto , Impressões Digitais de DNA , Análise Mutacional de DNA , Feminino , Mutação da Fase de Leitura , Humanos , Masculino , Linhagem , Análise de Sequência de DNA
18.
Hum Mol Genet ; 5(6): 835-42, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8776600

RESUMO

Inherited mutations in the BRCA1 gene are known to confer a predisposition to breast and ovarian cancer. We have first characterized 19 sequence variants in the BRCA1 gene during mutation screening by direct sequencing using DNA samples from breast/ovarian cancer patients or obligate carriers. The frequencies of these sequence variants were then compared with those found in control populations of women. Among the 10 sequence variants showing an estimated frequency of the less common allele above 0.05, Q/R356, L/P871, E/G1038, K/R1183 and S/G1613 result in a change of amino acids, 2201C/T, 2430T/C and 4427C/T are silent mutations and the two others, 4209-141C/A and 5272 + 66A/G, are intronic polymorphisms. These frequent polymorphisms, with the exception of Q/R356, were in complete or significant pairwise linkage disequilibrium as evaluated in our control populations. With one exception (L/P871), none of these variants had statistically significant (P < 0.05) differences in allele frequency between breast/ovarian cancer patients or obligate carriers and our control populations. Four rare sequence variants designated 710C-->T, D693N, R841W and S1040N were found in both unaffected and breast/ovarian cancer populations, while the missense mutations M1008I, E1219D, R1347G, T1561I and M1628V were detected only once in our patient population. When a functional test is available, it will be important to determine the consequence on the BRCA1 activity of these rare sequence variants and missense mutations.


Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Neoplasias Ovarianas/genética , Polimorfismo Genético , Neoplasias da Mama/metabolismo , Linhagem Celular Transformada , Feminino , Frequência do Gene , Humanos , Mutação , Neoplasias Ovarianas/metabolismo
19.
Am J Hum Genet ; 58(2): 271-80, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8571953

RESUMO

Several BRCA1 mutations have now been found to occur in geographically diverse breast and ovarian cancer families. To investigate mutation origin and mutation-specific phenotypes due to BRCA1, we constructed a haplotype of nine polymorphic markers within or immediately flanking the BRCA1 locus in a set of 61 breast/ovarian cancer families selected for having one of six recurrent BRCA1 mutations. Tests of both mutations and family-specific differences in age at diagnosis were not significant. A comparison of the six mutations in the relative proportions of cases of breast and ovarian cancer was suggestive of an effect (P = .069), with 57% of women presumed affected because of the 1294 del 40 BRCA1 mutation having ovarian cancer, compared with 14% of affected women with the splice-site mutation in intron 5 of BRCA1. For the BRCA1 mutations studied here, the individual mutations are estimated to have arisen 9-170 generations ago. In general, a high degree of haplotype conservation across the region was observed, with haplotype differences most often due to mutations in the short-tandem-repeat markers, although some likely instances of recombination also were observed. For several of the instances, there was evidence for multiple, independent, BRCA1 mutational events.


Assuntos
Haplótipos/genética , Mutação , Proteínas de Neoplasias/genética , Fatores de Transcrição/genética , Alelos , Proteína BRCA1 , Neoplasias da Mama/genética , Mapeamento Cromossômico , Saúde da Família , Feminino , Marcadores Genéticos/genética , Genótipo , Humanos , Neoplasias Ovarianas/genética , Fenótipo , Polimorfismo Conformacional de Fita Simples
20.
Cytogenet Cell Genet ; 73(4): 304-7, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8751382

RESUMO

Two steroid 5 alpha-reductase isoenzymes catalyze the conversion of testosterone into dihydrotestosterone, the more bioactive androgen, which is essential for male phenotypic sexual differentiation and for androgen-mediated growth of such tissues and organs as the prostate. Inherited mutations in SRD5A2 cause male pseudohermaphroditism. The SRD5A1 and SRD5A2 genes encoding the steroid 5 alpha-reductase type 1 and type 2 isoenzymes have been previously assigned by in situ hybridization to 5p15 and 2p23, respectively. To map the SRD5A2 gene by linkage analysis, a novel RsaI RFLP detected in exon I and a TA repeat polymorphism found in exon V were genotyped in eight CEPH reference families. A two-point linkage analysis was performed between these polymorphisms and the chromosome 2 microsatellite markers of Généthon and NIH/CEPH. The closest linkage was observed with D2S352 (Zmax = 24.06; thetamax = 0.001) in the region 2p23-->p22. To further define the localization of SRD5A2, a framework map, including nine Généthon markers flanking the polymorphic SRD5A2 locus, was built by multipoint linkage analysis. This led to a high-resolution genetic map of the region flanking the polymorphic SRD5A2 gene, including the nine Généthon markers and three NIH/CEPH markers, yielded the following order: tel-D2S48-D2S149-D2S320-D2S171-D2S165- [D2S352/SRD5A2]-D2S367-[D2S19/D2S177]-[ D2S391/CALM]-D2S378-cen.


Assuntos
Cromossomos Humanos Par 2/genética , Genes , Isoenzimas/genética , Oxirredutases/genética , Sequência de Bases , Colestenona 5 alfa-Redutase , Mapeamento Cromossômico , Ligação Genética , Humanos , Escore Lod , Dados de Sequência Molecular , Reação em Cadeia da Polimerase
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