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Identical mutations in unrelated families with generalized resistance to thyroid hormone occur in cytosine-guanine-rich areas of the thyroid hormone receptor beta gene. Analysis of 15 families.

Weiss, R E; Weinberg, M; Refetoff, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1993 EN
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26.33%
Generalized resistance to thyroid hormone (GRTH) is a syndrome of variable reduction of tissue responsiveness to thyroid hormone. 28 different point mutations in the human thyroid hormone receptor beta (TR beta) gene have been associated with GRTH. These mutations are clustered in two regions of the T3 binding domain of the TR beta (codons 310-347 and 417-453). We now report point mutations in the TR beta gene of six additional families with GRTH and show that three mutations occurred each in three families with GRTH, and that three other mutations were each present in two families. In 11 of these 15 families, lack of a common ancestor could be confirmed by genetic analysis. 28 of the 38 point mutations so far identified, including all those occurring in more than one family, are located in cytosine-guanine-rich areas of the TR beta gene. Differences in clinical and laboratory findings in unrelated families harboring the same TR beta mutation suggest that genetic variability of other factors modulate the expression of thyroid hormone action.

Clinical and prognostic evaluation of familial hypertrophic cardiomyopathy in two South African families with different cardiac beta myosin heavy chain gene mutations.

Posen, B. M.; Moolman, J. C.; Corfield, V. A.; Brink, P. A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1995 EN
Relevância na Pesquisa
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BACKGROUND--Familial hypertrophic cardiomyopathy is the most common inherited cardiac disorder, with sudden cardiac death at a young age the most frequent cause of death in affected individuals. Some cases of familial hypertrophic cardiomyopathy are caused by missense mutations of the beta myosin heavy chain (beta MHC) gene on chromosome 14 and at least 17 such mutations have been described. Recent reports suggest that a correlation exists between a specific beta MHC gene mutation and prognosis in familial hypertrophic cardiomyopathy. This premise is currently being used as a basis to provide counselling for affected families. This mutation/prognosis association, however, has not been widely assessed as yet. The clinical and prognostic features of two South African families of mixed racial descent, in which different beta MHC gene mutations were segregating, were studied to evaluate this correlation. The results were compared with those of previously published reports of European families carrying the same mutations. METHODS--The beta MHC gene missense mutations in two affected families were identified by single strand conformation polymorphism analysis and sequencing (pedigree 106: Arg403Trp; pedigree 108: Arg249Gln). All family members were subjected to genotypic analysis using polymerase chain reaction amplification and restriction enzyme based mutation detection techniques. Clinical...

DNA microsatellite analysis of families with autosomal dominant polycystic kidney disease types 1 and 2: evaluation of clinical heterogeneity between both forms of the disease.

Coto, E; Sanz de Castro, S; Aguado, S; Alvarez, J; Arias, M; Menéndez, M J; López-Larrea, C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1995 EN
Relevância na Pesquisa
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We studied 17 large families affected by adult dominant polycystic kidney disease (ADPKD). Ultrasonographic analysis was performed on all the family members. DNA microsatellite markers closely linked to PKD1 on 16p13.3 were analysed, and linkage of the disease to this locus was determined. Families showing a negative linkage value were evaluated for linkage to the PKD2 locus on 4q. Five of the 17 families showed negative linkage for the 16p13.3 markers. In these families significant linkage to 4q was obtained. Renal cysts developed at an earlier age in PKD1 mutation carriers, and end stage renal failure occurred at an older age in people affected with PKD2. Analysis of large families with ADPKD in a Spanish population indicates that this is a genetically heterogeneous disorder, but mutations at only two loci are responsible for the development of the disease in most if not all the families. Clinicopathological differences between both forms of the disease occur, with subjects with ADPKD2 having a better prognosis than those with mutations at PKD1.

Genetic heterogeneity and HOMOG analysis in British malignant hyperthermia families.

Robinson, R; Curran, J L; Hall, W J; Halsall, P J; Hopkins, P M; Markham, A F; Stewart, A D; West, S P; Ellis, F R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1998 EN
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Malignant hyperthermia (MH) is an autosomal dominant genetic condition that presents in susceptible people undergoing general anaesthesia. The clinical disorder is a major cause of anaesthetic morbidity and mortality. The UK Malignant Hyperthermia Group has performed genetic linkage analysis on 20 large, well defined malignant hyperthermia families, using hypervariable markers on chromosome 19q13.1, including the candidate MH gene RYR1, the gene coding for the skeletal muscle ryanodine receptor protein. The results were analysed using LINKAGE to perform two point and multipoint lod scores, then HOMOG to calculate levels of heterogeneity. The results clearly showed genetic heterogeneity between MH families; nine of the families gave results entirely consistent with linkage to the region around RYR1 while the same region was clearly excluded in three families. In the remaining eight MHS families there were single recombinant events between RYR1 and MH susceptibility. HOMOG analysis was of little added benefit in determining the likelihood of linkage to RYR1 in these families. This confirmation of the presence of heterogeneity in the UK MH population, along with the possibility of the presence of two MH genes in some pedigrees, indicates that it would be premature and potentially dangerous to offer diagnosis of MH by DNA based methods at this time.

A common DLX3 gene mutation is responsible for tricho-dento-osseous syndrome in Virginia and North Carolina families.

Price, J A; Wright, J T; Kula, K; Bowden, D W; Hart, T C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1998 EN
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Tricho-dento-osseous syndrome (TDO) is characterised by a variable clinical phenotype primarily affecting the hair, teeth, and bone. Different clinical features are observed between and within TDO families. It is not known whether the variable clinical features are the result of genetic heterogeneity or clinical variability. A gene for TDO was localised recently to chromosome 17q21 in four North Carolina families, and a 4 bp deletion in the human distal-less 3 gene (DLX3) was identified in all affected members. A previous genetic linkage study in a large Virginia kindred with TDO indicated possible linkage to the ABO, Gc, and Kell blood group loci. To examine whether TDO exhibits genetic heterogeneity, we have performed molecular genetic analysis to determine whether affected members of this Virginia kindred have the DLX3 gene deletion identified in North Carolina families. Results show that affected subjects (n=3) from the Virginia family have the same four nucleotide deletion previously identified in the North Carolina families. A common haplotype for three genetic markers surrounding the DLX3 gene was identified in all affected subjects in the North Carolina and Virginia families. These findings suggest that all people with TDO who have been evaluated have inherited the same DLX3 gene deletion mutation from a common ancestor. The variable clinical phenotype observed in these North Carolina and Virginia families...

Germline PTEN mutations in Cowden syndrome-like families.

Marsh, D J; Dahia, P L; Caron, S; Kum, J B; Frayling, I M; Tomlinson, I P; Hughes, K S; Eeles, R A; Hodgson, S V; Murday, V A; Houlston, R; Eng, C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1998 EN
Relevância na Pesquisa
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Cowden syndrome (CS) or multiple hamartoma syndrome (MIM 158350) is an autosomal dominant disorder with an increased risk for breast and thyroid carcinoma. The diagnosis of CS, as operationally defined by the International Cowden Consortium, is made when a patient, or family, has a combination of pathognomonic major and/or minor criteria. The CS gene has recently been identified as PTEN, which maps at 10q23.3 and encodes a dual specificity phosphatase. PTEN appears to function as a tumour suppressor in CS, with between 13-80% of CS families harbouring germline nonsense, missense, and frameshift mutations predicted to disrupt normal PTEN function. To date, only a small number of tumour suppressor genes, including BRCA1, BRCA2, and p53, have been associated with familial breast or breast/ovarian cancer families. Given the involvement of PTEN in CS, we postulated that PTEN was a likely candidate to play a role in families with a "CS-like" phenotype, but not classical CS. To answer these questions, we gathered a series of patients from families who had features reminiscent of CS but did not meet the Consortium Criteria. Using a combination of denaturing gradient gel electrophoresis (DGGE), temporal temperature gel electrophoresis (TTGE)...

A Combined Genomewide Linkage Scan of 1,233 Families for Prostate Cancer–Susceptibility Genes Conducted by the International Consortium for Prostate Cancer Genetics

Xu, Jianfeng; Dimitrov, Latchezar; Chang, Bao-Li; Adams, Tamara S.; Turner, Aubrey R.; Meyers, Deborah A.; Eeles, Rosalind A.; Easton, Douglas F.; Foulkes, William D.; Simard, Jacques; Giles, Graham G.; Hopper, John L.; Mahle, Lovise; Moller, Pal; Bishop,
Fonte: The American Society of Human Genetics Publicador: The American Society of Human Genetics
Tipo: Artigo de Revista Científica
EN
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Evidence of the existence of major prostate cancer (PC)–susceptibility genes has been provided by multiple segregation analyses. Although genomewide screens have been performed in over a dozen independent studies, few chromosomal regions have been consistently identified as regions of interest. One of the major difficulties is genetic heterogeneity, possibly due to multiple, incompletely penetrant PC-susceptibility genes. In this study, we explored two approaches to overcome this difficulty, in an analysis of a large number of families with PC in the International Consortium for Prostate Cancer Genetics (ICPCG). One approach was to combine linkage data from a total of 1,233 families to increase the statistical power for detecting linkage. Using parametric (dominant and recessive) and nonparametric analyses, we identified five regions with “suggestive” linkage (LOD score >1.86): 5q12, 8p21, 15q11, 17q21, and 22q12. The second approach was to focus on subsets of families that are more likely to segregate highly penetrant mutations, including families with large numbers of affected individuals or early age at diagnosis. Stronger evidence of linkage in several regions was identified, including a “significant” linkage at 22q12...

A Single Genetic Origin for the G101W CDKN2A Mutation in 20 Melanoma-Prone Families

Ciotti, Paola; Struewing, Jeffery P.; Mantelli, Michela; Chompret, Agnès; Avril, Marie-Françoise; Santi, Pier Luigi; Tucker, Margaret A.; Bianchi-Scarrà, Giovanna; Bressac-de Paillerets, Brigitte; Goldstein, Alisa M.
Fonte: The American Society of Human Genetics Publicador: The American Society of Human Genetics
Tipo: Artigo de Revista Científica
EN
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Germline mutations within the coding region of CDKN2A have been observed in affected members of melanoma-prone families. G101W is the most common CDKN2A missense mutation identified to date. It has been reported in several families from around the world, with a particularly high occurrence in France and Italy. Given the frequency of this mutation, we were interested in determining whether the mutation resulted from a single origin or represented a mutational hotspot in the CDKN2A gene. In addition, given the geographical distribution of the mutation, we examined the date of origination of the mutation and its migratory spread. We examined 10 families from Italy, 4 families from the United States, and 6 families from France with the G101W mutation. The following eight markers were employed for the haplotype analysis: IFNA, D9S736, D9S1749, D9S942, D9S1748, D9S1604, D9S171, and D9S126. Our findings showed no significant evidence for mutational heterogeneity, suggesting that all studied families derived from a single ancestral haplotype on which the mutation arose. Using maximum-likelihood methods, we estimated the mutation to have arisen 97 generations ago (1-LOD-unit support interval 70–133 generations) providing some explanation for the wide geographical spread of this common mutation...

Founder BRCA1 and BRCA2 mutations in French Canadian breast and ovarian cancer families.

Tonin, P N; Mes-Masson, A M; Futreal, P A; Morgan, K; Mahon, M; Foulkes, W D; Cole, D E; Provencher, D; Ghadirian, P; Narod, S A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1998 EN
Relevância na Pesquisa
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We have identified four mutations in each of the breast cancer-susceptibility genes, BRCA1 and BRCA2, in French Canadian breast cancer and breast/ovarian cancer families from Quebec. To identify founder effects, we examined independently ascertained French Canadian cancer families for the distribution of these eight mutations. Mutations were found in 41 of 97 families. Six of eight mutations were observed at least twice. The BRCA1 C4446T mutation was the most common mutation found, followed by the BRCA2 8765delAG mutation. Together, these mutations were found in 28 of 41 families identified to have a mutation. The odds of detection of any of the four BRCA1 mutations was 18.7x greater if one or more cases of ovarian cancer were also present in the family. The odds of detection of any of the four BRCA2 mutations was 5.3x greater if there were at least five cases of breast cancer in the family. Interestingly, the presence of a breast cancer case <36 years of age was strongly predictive of the presence of any of the eight mutations screened. Carriers of the same mutation, from different families, shared similar haplotypes, indicating that the mutant alleles were likely to be identical by descent for a mutation in the founder population. The identification of common BRCA1 and BRCA2 mutations will facilitate carrier detection in French Canadian breast cancer and breast/ovarian cancer families.

Emergence of Protein Fold Families through Rational Design

Ding, Feng; Dokholyan, Nikolay V
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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Diverse proteins with similar structures are grouped into families of homologs and analogs, if their sequence similarity is higher or lower, respectively, than 20%–30%. It was suggested that protein homologs and analogs originate from a common ancestor and diverge in their distinct evolutionary time scales, emerging as a consequence of the physical properties of the protein sequence space. Although a number of studies have determined key signatures of protein family organization, the sequence-structure factors that differentiate the two evolution-related protein families remain unknown. Here, we stipulate that subtle structural changes, which appear due to accumulating mutations in the homologous families, lead to distinct packing of the protein core and, thus, novel compositions of core residues. The latter process leads to the formation of distinct families of homologs. We propose that such differentiation results in the formation of analogous families. To test our postulate, we developed a molecular modeling and design toolkit, Medusa, to computationally design protein sequences that correspond to the same fold family. We find that analogous proteins emerge when a backbone structure deviates only 1–2 Å root-mean-square deviation from the original structure. For close homologs...

Occurrence of lymphocytotoxins in multi-case rheumatoid arthritis families: relation to HLA.

Taneja, V; Mehra, N K; Singh, R R; Anand, C; Malaviya, A N
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1991 EN
Relevância na Pesquisa
26.33%
The presence of lymphocytotoxic antibodies (LCA) and their association with HLA haplotypes has been studied in 27 multi-case rheumatoid arthritis (RA) families (13 multiplex and 14 simplex) in Northern India. Of the total 59 RA patients, 69.4% had cytotoxins in their sera as compared with 2.5% of healthy controls. No differences were observed in the frequency of LCA in relation to sex and rheumatoid factor. LCA against B cells were significantly more predominant than those against T cells. Twenty families studied for correlation of HLA with LCA showed greater intensity of reaction with DR4+ haplotypes, particularly in simplex families. Similarly, the frequency of LCA among patients and unaffected parents was greater in simplex compared with multiplex families. Haplotype sharing with the patient was increased in the relatives positive for cytotoxins in these families. An immunogenetic contribution made by the affected parent and a common environmental stimulus may be responsible for the increased production of LCA in multi-case families with RA.

Reduction of Sample Heterogeneity through Use of Population Substructure: An Example from a Population of African American Families with Sarcoidosis

Thompson, Cheryl L.; Rybicki, Benjamin A.; Iannuzzi, Michael C.; Elston, Robert C.; Iyengar, Sudha K.; Gray-McGuire, Courtney;
Fonte: The American Society of Human Genetics Publicador: The American Society of Human Genetics
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.33%
Sarcoidosis is a granulomatous inflammatory disorder of complex etiology with significant linkage to chromosome 5, and marginal linkage was observed to five other chromosomes in African Americans (AAs) in our previously published genome scan. Because genetic factors underlying complex disease are often population specific, genetic analysis of samples with diverse ancestry (i.e., ethnic confounding) can lead to loss of power. Ethnic confounding is often addressed by stratifying on self-reported race, a controversial and less-than-perfect construct. Here, we propose linkage analysis stratified by genetically determined ancestry as an alternative approach for reducing ethnic confounding. Using data from the 380 microsatellite markers genotyped in the aforementioned genome scan, we clustered AA families into subpopulations on the basis of ancestry similarity. Evidence of two genetically distinct groups was found: subpopulation one (S1) comprised 219 of the 229 families, subpopulation two (S2) consisted of six families (the remaining four families were a mixture). Stratified linkage results suggest that only the S1 families contributed to previously identified linkage signals at 1p22, 3p21-14, 11p15, and 17q21 and that only the S2 families contributed to those found at 5p15-13 and 20q13. Signals on 2p25...

Linkage analysis of chromosome 17q markers and breast-ovarian cancer in Icelandic families, and possible relationship to prostatic cancer.

Arason, A; Barkardóttir, R B; Egilsson, V
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1993 EN
Relevância na Pesquisa
26.33%
Seven families, selected for breast cancer segregation, have been analyzed for chromosome 17q12-q23 linkage to breast and ovarian cancer. In two of them, linkage is seen with most markers tested, increasing toward the most proximal region, but without informative recombinations above NM23. In the remaining families, no linkage is observed. Families with 17q linkage are not easily distinguished by clinical characteristics such as early onset (mean age at diagnosis < or = 45 years) or organs involved. In fact, the family with the highest lod scores (> or = 2.3) belongs to the "later onset" (> 45 years) category of families. Interestingly, prostatic cancer is the most frequent malignancy, after breast cancer, in the families that we studied (13 cases total, all metastasizing) and is especially prevalent in males presumed to carry the trait. Of 16 paternal carriers, 7 (44%) had developed prostatic cancer. Haplotype analysis in families with 17q linkage reveals two further prostatic cases as potential carriers. We propose that breast cancer genes may predispose to prostatic cancer in male carriers.

Cystic fibrosis mutations in North American populations of French ancestry: Analysis of Quebec French-Canadian and Louisiana Acadian families

Rozen, Rima; Schwartz, Robert H.; Hilman, Bettina C.; Stanislovitis, Pat; Horn, Glenn T.; Klinger, Katherine; Daigneault, Jocelyne; De Braekeleer, Marc; Kerem, Bat-sheva; Tsui, Lap-Chee; Fujiwara, T. Mary; Morgan, Kenneth
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1990 EN
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26.33%
A 3-bp deletion (ΔF508) in the cystic fibrosis (CF) gene is the mutation on the majority of CF chromosomes. We studied 112 CF families from North American populations of French ancestry: French-Canadian families referred from hospitals in three cities in Quebec and from the Saguenay-Lac St. Jean region of northeastern Quebec and Acadian families living in Louisiana. ΔF508 was present on 71%, 55%, and 70% of the CF chromosomes from the major-urban Quebec, Saguenay-Lac St. Jean, and Louisiana Acadian families, respectively. A weighted estimate of the proportion of ΔF508 in the French-Canadian patient population of Quebec was 70%. We found that 95% of the CF chromosomes with ΔF508 had D7S23 haplotype B, the most frequent haplotype on CF chromosomes. In the Saguenay-Lac St. Jean families, 86% of the CF chromosomes without ΔF508 had the B haplotype, compared with 31% for the major-urban Quebec and Louisiana Acadian families. The incidence of CF in the Saguenay-Lac St. Jean population was 1/895 live-born infants.

Nonsyndromic cleft lip with or without cleft palate: evidence of linkage to BCL3 in 17 multigenerational families.

Stein, J; Mulliken, J B; Stal, S; Gasser, D L; Malcolm, S; Winter, R; Blanton, S H; Amos, C; Seemanova, E; Hecht, J T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1995 EN
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Nonsyndromic cleft lip with or without cleft palate (CL/P) is a common craniofacial developmental defect. Recent segregation analyses have suggested that major genes play a role in the etiology of CL/P. Linkage to 22 candidate genes was tested in 11 multigenerational families with CL/P, and 21 of these candidates were excluded. APOC2, 19q13.1, which is linked to the proto-oncogene BCL3, gave suggestive evidence for linkage to CL/P. The study was expanded to include a total of 39 multigenerational CL/P families. Linkage was tested in all families, using an anonymous marker, D19S178, and intragenic markers in BCL3 and APOC2. Linkage was tested under two models, autosomal dominant with reduced penetrance and affecteds only. Homogeneity testing on the two-point data gave evidence of heterogeneity at APOC2 under the affecteds-only model. Both models showed evidence of heterogeneity, with 43% of families linked at zero recombination to BCL3 when marker data from BCL3 and APOC2 were included. A maximum multipoint LOD score of 7.00 at BCL3 was found among the 17 families that had posterior probabilities > = 50% in favor of linkage. The transmission disequilibrium test provided additional evidence for linkage with the 3 allele of BCL3 more often transmitted to affected children. These results suggest that BCL3...

The origin and evolution of human ampliconic gene families and ampliconic structure

Bhowmick, Bejon Kumar; Satta, Yoko; Takahata, Naoyuki
Fonte: Cold Spring Harbor Laboratory Press Publicador: Cold Spring Harbor Laboratory Press
Tipo: Artigo de Revista Científica
Publicado em /04/2007 EN
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26.33%
Out of the nine male-specific gene families in the human Y chromosome amplicons, we investigate the origin and evolution of seven families for which gametologous and orthologous sequences are available. Proto-X/Y gene pairs in the original mammalian sex chromosomes played major roles in origins and gave rise to five gene families: XKRY, VCY, HSFY, RBMY, and TSPY. The divergence times between gametologous X- and Y-linked copies in these families are well correlated with the former X-chromosomal locations. The CDY and DAZ families originated exceptionally by retroposition and transposition of autosomal copies, respectively, but CDY possesses an X-linked copy of enigmatic origin. We also investigate the evolutionary relatedness among Y-linked copies of a gene family in light of their ampliconic locations (palindromes, inverted repeats, and the TSPY array). Although any pair of copies located at the same arm positions within a palindrome is identical or nearly so by frequent gene conversion, copies located at different arm positions are distinctively different. Since these and other distinct copies in various gene families were amplified almost simultaneously in the stem lineage of Catarrhini, we take these simultaneous amplifications as evidence for the elaborate formation of Y ampliconic structure. Curiously...

Screening of male breast cancer and of breast-ovarian cancer families for BRCA2 mutations using large bifluorescent amplicons

Pages, S; Caux, V; Stoppa-Lyonnet, D; Tosi, M
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /02/2001 EN
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26.33%
41 breast cancer or breast-ovarian cancer families, including 12 families with at least one affected first-degree male relative, were screened for mutations in the BRCA2 gene. Mutations had not been found in the BRCA1 gene of these families. Chemical cleavage of Mismatch was used to identify nucleotide changes within large PCR products (average size 1.2 kb) that carried strand-specific fluorescent end-labels. 15 amplicons were sufficient to scan 18 exons, including the large exon 11. The remaining 9 small exons were examined by Denaturing Gradient Gel Electrophoresis. The high sensitivity of this approach was documented by the detection, in these 41 patients, of all 9 exonic single nucleotide polymorphisms reported with heterozygosity >0.1. Truncating BRCA2 mutations were found in 7 of the 41 families. 3 of them were in the group of 12 families comprising cases of male breast cancer. Since the methods used here have no bias for particular types of mutations, these data confirm the high proportion of frameshifts among mutations in BRCA2. However, relevant single nucleotide substitutions were also found: one resulting in a stop codon and another one, present in a male patient, was the previously reported change Asp2723His, that affects a highly conserved region of the BRCA2 protein. This study indicates a BRCA2 contribution of 10% (95% CI 2.5–17.5) to our original cohort of 59 breast-ovarian cancer families...

A probability model for predicting BRCA1 and BRCA2 mutations in breast and breast-ovarian cancer families

Vahteristo, P; Eerola, H; Tamminen, A; Blomqvist, C; Nevanlinna, H
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /03/2001 EN
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Germline mutations in BRCA1 and BRCA2 genes predispose to hereditary breast and ovarian cancer. Our aim was to find associations between the clinical characteristics and positive mutation status in 148 breast cancer families in order to predict the probability of finding a BRCA mutation in a family. Several factors were associated with mutations in univariate analysis, whereas in multivariate analysis (logistic regression with backward selection) only the age of the youngest breast cancer patient and the number of ovarian cancer cases in a family were independent predictors of BRCA mutations. A logistic model was devised to estimate the probability for a family of harbouring a mutation in either BRCA1 or BRCA2. Altogether, 63 out of 148 families (43%) and 28 out of 29 (97%) mutation carrier families obtained probabilities over 10%. The mean probability was 55% for mutation-positive families and 11% for mutation-negative families. The models by Couch et al (1997) and Shattuck-Eidens et al (1997) previously designed for BRCA1 were also tested for their applicability to distinguish carrier families with mutations in either gene. The probability model should be a useful tool in genetic counselling and focusing the mutation analyses, and thus increasing also the cost-effectiveness of the genetic screening. © 2001 Cancer Research Campaign http://www.bjcancer.com

Distribution of Pneumococcal Surface Protein A Families 1 and 2 among Streptococcus pneumoniae Isolates from Children in Finland Who Had Acute Otitis Media or Were Nasopharyngeal Carriers▿

Melin, Merit M.; Hollingshead, Susan K.; Briles, David E.; Hanage, William P.; Lahdenkari, Mika; Kaijalainen, Tarja; Kilpi, Terhi M.; Käyhty, Helena M.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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PspA is a structurally variable surface protein important to the virulence of pneumococci. PspAs are serologically cross-reactive and exist as two major families. In this study, we determined the distribution of PspA families 1 and 2 among pneumococcal strains isolated from the middle ear fluid (MEF) of children with acute otitis media and from nasopharyngeal specimens of children with pneumococcal carriage. We characterized the association between the two PspA families, capsular serotypes, and multilocus sequence types (STs) of the pneumococcal isolates. MEF isolates (n = 201) of 109 patients and nasopharyngeal isolates (n = 173) of 49 children were PspA family typed by whole-cell enzyme immunoassay (EIA). Genetic typing (PCR) of PspA family was done for 60 isolates to confirm EIA typing results. The prevalences of PspA families 1 and 2 were similar among pneumococci isolated from MEF (51% and 45%, respectively) and nasopharyngeal specimens (48% each). Isolates of certain capsule types as well as isolates of certain STs showed statistical associations with either family 1 or family 2 PspA. Pneumococci from seven children with multiple pneumococcal isolates appeared to express serologically different PspA families in different isolates of the same serotype; in three of the children the STs of the isolates were the same...

Germline CDH1 deletions in hereditary diffuse gastric cancer families

Oliveira, Carla; Senz, Janine; Kaurah, Pardeep; Pinheiro, Hugo; Sanges, Remo; Haegert, Anne; Corso, Giovanni; Schouten, Jan; Fitzgerald, Rebecca; Vogelsang, Holger; Keller, Gisela; Dwerryhouse, Sarah; Grimmer, Donna; Chin, Suet-Feung; Yang, Han-Kwang; Jac
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
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Germline CDH1 point or small frameshift mutations can be identified in 30–50% of hereditary diffuse gastric cancer (HDGC) families. We hypothesized that CDH1 genomic rearrangements would be found in HDGC and identified 160 families with either two gastric cancers in first-degree relatives and with at least one diffuse gastric cancer (DGC) diagnosed before age 50, or three or more DGC in close relatives diagnosed at any age. Sixty-seven carried germline CDH1 point or small frameshift mutations. We screened germline DNA from the 93 mutation negative probands for large genomic rearrangements by Multiplex Ligation-Dependent Probe Amplification. Potential deletions were validated by RT–PCR and breakpoints cloned using a combination of oligo-CGH-arrays and long-range-PCR. In-silico analysis of the CDH1 locus was used to determine a potential mechanism for these rearrangements. Six of 93 (6.5%) previously described mutation negative HDGC probands, from low GC incidence populations (UK and North America), carried genomic deletions (UK and North America). Two families carried an identical deletion spanning 193 593 bp, encompassing the full CDH3 sequence and CDH1 exons 1 and 2. Other deletions affecting exons 1, 2, 15 and/or 16 were identified. The statistically significant over-representation of Alus around breakpoints indicates it as a likely mechanism for these deletions. When all mutations and deletions are considered...