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At least 127 records · Page 7Linked to original sources
PubMed1999

Visual impairment and REP-1 gene mutations in Japanese choroideremia patients.

Choroideremia (CHM), an X-linked recessive hereditary disease, is an intractable chorioretinal dystrophy. The rate of disease progression of CHM reportedly shows considerable variability. A number of mutations involving the gene that codes for Rab escort protein-1 (REP-1) have been detected in CHM patients. We have analyzed REP-1 gene mutations of Japanese CHM patients. The present study was designed to investigate the clinical variability and the genotype to phenotype relationship in 15 Japanese CHM patients referred to the Department of Ophthalmology of Juntendo University Hospital. The clinical investigation of visual acuity, visual field, color vision and refraction revealed inter-individual variability. Mutation analyses of the REP-1 gene revealed 10 types of mutations in 13 patients from 11 families, including an insertion, small deletions, nonsense mutations and an A to CC mutation. In 13 CHM patients with detectable REP-1 gene mutations, no relationship of genotype to phenotype was detected. At present, we consider the REP-1 genotype to be an unreliable prognostic factor for counseling of CHM patients. In two patients from one family, no mutations were detected in coding regions of the REP-1 gene. These patients may have intron mutations of the REP-1 gene, not detectable by the techniques employed in this study, or other causative genes. Both were observed to have somewhat slower disease progression than the other 13 patients. More advanced analyses are necessary to answer questions regarding the genotype-phenotype relationship in CHM patients.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Peutz-Jeghers syndrome: four novel inactivating germline mutations in the STK11 gene. Mutations in brief no. 227. Online.

The diagnosis of Peutz-Jeghers syndrome is based on the occurrence of hamartomatous gastrointestinal polyps and perioral pigment spots. In view of the development of hamartomatous polyps in several syndromes and the variability of pigment spots in Peutz-Jeghers patients, identification of affected individuals is difficult. Recently, germline mutations in the STK11 gene have been reported as a molecular cause of Peutz-Jeghers syndrome. We present four novel inactivating mutations identified by direct sequencing of all 9 exons of the STK11 gene in 4 patients suggestive of Peutz-Jeghers syndrome: three frameshift mutations (125-137del; 474-480del; 516-517insT) and one nonsense mutation (Q220X). Our data obtained in these patients and in those reported previously emphasize the diagnostic value of histological discrimination between different types of hamartomatous polyps and of molecular analysis, particularly in cases with no family history of the disease.

AMP-Activated Protein Kinase Kinases↗
PubMed2006

Increased risk of gastrointestinal lymphoma in carriers of the 657del5 NBS1 gene mutation.

The NBS1 gene mutation, 657del5, frequent in the Slavic populations of Central Europe, is found in most patients with Nijmegen breakage syndrome (NBS), a recessive autosomal disorder with a very high incidence of non-Hodgkin lymphoma (NHL). We have previously described 2 heterozygous 657del5 mutation carriers among 42 adult NHL probands from Central Poland. Here we report 6 additional carriers of the 657del5 mutation and 2 carriers of the pathogenic NBS1 R215W mutation, among 186 other NHL patients also from Central Poland. The 657del5 carrier frequency in the pooled group of these 228 patients was significantly higher than in population controls (OR 5.85, 95% CI: 2.29-15.00, p = 0.0001). Interestingly, 4 of these carriers were found among 37 patients with gastrointestinal lymphoma (OR 19.52, 95% CI: 5.82-65.42, p = 0.0002). These findings imply that heterozygous NBS1 germline mutations may contribute significantly to the overall incidence of NHL, especially of the gastrointestinal tract, in Central Europe.

Adolescent↗
PubMed2000

The mammalian gene mutation database.

The Mammalian Gene Mutation Database (MGMD) is a comprehensive collection of published mutation data from the open literature on mammalian cell-based gene model mutation detection systems. The database currently contains approximately 30000 comprehensively described mutant spectra records and it is maintained and up- dated on a daily basis. The major objectives of the MGMD were (i) to provide an Internet-accessible database (http://lisntweb.swan.ac. uk/cmgt/index.htm) for chemically induced and spontaneous mutation types and spectra in selected genes; (ii) to standardize the reporting of mutations within different genes where ambiguity exists in the literature; and (iii) to provide interactive and user-friendly access to the information. A multi-option search facility has been included that allows the user to search the database for parameters such as mutagen, gene or cell type of interest. The structure of the database permits easy retrieval of specific mutation data for further analysis. Thus, the MGMD should become a useful and necessary reference source and provides an analysis tool for genetic toxicologists.

Animals↗
PubMed2004

Molecular cloning and characterization of the catalytic domain of zebrafish homologue of the ataxia-telangiectasia mutated gene.

Inherited biallelic mutations of the ATM (ataxia-telangiectasia mutated) gene in humans cause ataxia-telangiectasia, a rare autosomal recessive disorder associated with progressive neuro-degeneration, cancer predisposition, immunodeficiency, and hypersensitivity to ionizing radiation. The ATM gene is highly conserved across a wide range of species. In an attempt to establish a zebrafish (Danio rerio) model of ataxia-telangiectasia, we cloned the coding sequence of the catalytic domain of the zebrafish homologue of ATM and found it to contain an open reading frame encoding 907 amino acids at the carboxyl terminus of the zebrafish ATM (zATM). The catalytic domain of zATM shares 67% and 66% homology with human ATM (hATM) and mouse ATM (mATM), respectively. The full-length mRNA encoding zATM is found to be approximately 11 kb by Northern hybridization, and the expression of zATM is observed in different adult and embryonic tissues. Overexpression of a kinase-inactive zATM domain in human cells has a dominant-negative effect against hATM function. Expression of the altered zATM in ZF4 cells leads to an A-T-like phenotype in response to ionizing radiation. These results taken together indicate that zATM is the homologue of hATM. Furthermore, using the kinase-inactive form of zATM should allow manipulation of zATM function in fish cells.

Amino Acid Sequence↗
PubMed2005

Autoimmune regulator-1 messenger ribonucleic acid analysis in a novel intronic mutation and two additional novel AIRE gene mutations in a cohort of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy patients.

CONTEXT: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disease associated with mutations in the AIRE gene. OBJECTIVE: Our objective was to investigate clinical and mutational characteristics of 12 Slovenian patients from 10 families with APECED. METHODS: Direct sequencing, restriction fragment length polymorphism, and amplification refractory mutation system analyses were used to identify AIRE gene mutations. Autoimmune regulator (AIRE)-1 mRNA analysis was used to confirm pathogenicity of the intronic mutation. RESULTS: The prevalence of APECED in Slovenian population was estimated to be 1 in 43,000, which is significantly higher compared with the neighboring populations. Three novel mutations were identified among six different mutations detected in the AIRE gene. The first novel mutation was an intronic mutation (653-7_-5delCTC) affecting proper splicing by using a nearby new acceptor splice site as demonstrated by AIRE-1 mRNA analyses. The second and third novel mutations were frame-shift mutations located in exon 5 (540delG) and exon 9 (1064-1068dupCCCGG), both leading to premature truncation of the AIRE protein. The Finnish R257X mutation was the most frequent AIRE gene mutation in Slovenian patients with APECED (16 of 24 alleles). CONCLUSIONS: Three novel AIRE gene mutations were identified. For the first time, a novel intronic mutation was investigated on the mRNA level in APECED. This could be particularly important for APECED patients where no or only heterozygous mutation on the genomic DNA level is detected.

Adolescent↗
PubMed2003

Influence of LDL receptor gene mutations and the R3500Q mutation of the apoB gene on lipoprotein phenotype of familial hypercholesterolemic patients from a South European population.

Few data are available on genotype-phenotype interactions among familial hypercholesterolemia (FH) patients in South European populations and there are no data about the influence of R3500Q mutation on lipoprotein phenotype compared to low-density lipoprotein receptor (LDLR) mutations. The objective of the study is to analyze the influence of mutations in the LDLR and apolipoprotein B (apoB) genes on lipoprotein phenotype among subjects clinically diagnosed of FH living in East Spain. In all, 113 FH index patients and 100 affected relatives were studied. Genetic diagnosis was carried out following a protocol based on Southern blot and PCR-SSCP analysis. A total of 118 FH subjects could be classified into three groups according to the type of LDLR mutations (null mutations, missense mutations affecting the ligand binding 3-5 repeat, and missense mutations outside this domain). In addition, the lipoprotein phenotype of these FH groups was compared with 19 heterozygous subjects with familial ligand-defective apoB (FDB), due to R3500Q mutation. FH patients carrying missense mutations affecting the ligand binding repeat 3-5 showed total and LDL cholesterol levels significantly higher than FH patients with missense mutations in other LDLR domains or FDB patients. FH subjects carrying null mutations showed lower high-density lipoprotein cholesterol plasma values compared to FH carrying missense mutations. FDB subjects showed the lowest total and LDL cholesterol plasma values. In conclusion, the type of LDLR gene mutation and R3500Q mutation influences the lipoprotein phenotype of FH population from East Spain.

Adolescent↗
PubMed2001

Survey of factor V leiden and prothrombin gene mutations in systemic lupus erythematosus.

The two most common hereditary risk factors for thrombosis are factor V Leiden mutation and a prothrombin gene mutation. There is indeed a thrombotic tendency in patients with systemic lupus erythematosis (SLE) and it is not always associated with antiphospholipid antibodies. We aimed to determine the relationship between both factor V Leiden and prothrombin gene mutations and SLE. Using polymerase chain reaction (PCR) the factor V Leiden and prothrombin gene mutations were evaluated in 55 patients (20 children and 35 adults) with SLE. Although seven patients were found to have factor V Leiden mutation in the heterozygous state, two had the heterozygous G-->A (20210) prothrombin gene mutation. Although one had these two mutations concurrently, these two patients did not have thrombosis. The factor V Leiden mutation frequency (12.7%) was higher than that of our general population (7.1%). On the other hand, seven of the patients with SLE had a thrombotic event. Although of these seven, four (57%) had factor V Leiden mutation, three (43%) had no mutation. Of 48 patients with no thrombotic history, only three had the factor V mutation (6.25%). The prevalence of the factor V Leiden mutation in SLE patients with and without thrombosis was significantly different by Fisher's exact test (p<0.05). The risk of venous thrombosis in patients with factor V Leiden increased threefold compared to that in those without factor V Leiden mutation (odds ratio 20.1; CI 2.99-133.6). Although factor V Leiden mutation seems to play a role in the development of venous thrombosis in SLE, the development of thrombosis in SLE is multifactorial.

Adolescent↗
PubMed2003

Association between hemochromatosis (HFE) gene mutation carrier status and the risk of colon cancer.

BACKGROUND: Iron is a pro-oxidant that may promote carcinogenesis. Mutations in the hemochromatosis (HFE) gene are associated with increased total body iron stores in some individuals. We assessed the risk of colon cancer among individuals with and without HFE gene mutations. METHODS: We performed a population-based, case-control study in North Carolina. Case patients with colon cancer and control subjects provided information on multiple environmental exposures, including total iron intake and nonsteroidal anti-inflammatory drug (NSAID) use. They also provided a venous blood sample, from which DNA was extracted, amplified, and subjected to diagnostic restriction enzyme mapping to detect two major HFE gene mutations, C282Y and H63D. Data were analyzed with Fisher's exact test and logistic regression. All statistical tests were two-sided. RESULTS: Thirteen hundred and eight subjects participated (475 case patients, 833 control subjects). The allele frequencies of the H63D and C282Y mutations were greater among case patients (0.11 and 0.046, respectively) than among control subjects (0.09 and 0.044, respectively; P =.14 and P =.85, respectively). When we controlled for age, race, sex, red meat consumption, NSAID use, and total iron intake, subjects with any HFE gene mutation were more likely to have colon cancer than subjects with no HFE gene mutations (adjusted odds ratio [OR] = 1.40, 95% confidence interval [CI] = 1.07 to 1.87). The magnitude of the effect was similar for both the H63D (adjusted OR = 1.44, 95% CI = 1.04 to 1.98) and C282Y mutations (adjusted OR = 1.39, 95% CI = 0.88 to 2.19). The risk of colon cancer associated with an HFE gene mutation was similar for those who did and did not have a family history of colon cancer. Among those with HFE mutations, cancer risk increased with increasing age and total iron intake. CONCLUSIONS: HFE gene mutations are associated with an increased risk of colon cancer. Cancer risk is greatest in mutation carriers who are older or consume high quantities of iron.

Age Factors↗
PubMed2002

K-ras and p53 gene mutations in noncancerous biliary lesions of patients with pancreaticobiliary maljunction.

BACKGROUND/PURPOSE: We investigated the molecular mechanisms of carcinogenesis in the biliary epithelium in patients with pancreaticobiliary maljunction. METHODS: Point mutations of the K- ras gene and the p53 gene, and the overexpression of p53 gene products were examined in the cancerous and noncancerous biliary epithelium of 37 patients with pancreaticobiliary maljunction, with or without biliary dilatation. RESULTS: In the gallbladder epithelium of 5 patients with pancreaticobiliary maljunction associated with biliary carcinoma, K- ras gene mutations were detected in 3 (60%), p53 gene mutations in 3 (60%), and the overexpression of p53 gene products in 4 (80%), while in the bile duct epithelium of these patients, these features were found in 2 of 3 (66.7%), in all of 3 (100%), and none of 3 (0%) specimens, respectively. In the gallbladder epithelium of patients with pancreaticobiliary maljunction without biliary carcinoma, K- ras gene mutations were detected in 8 of 24 (33.3%) specimens, p53 gene mutations were detected in 16 of 27 specimens (59.3%), and the overexpression of p53 protein was detected in 5 of 27 (18.5%) specimens, while in the bile duct epithelium of these patients, these features were found in 10 of 25 (40%) specimens, 14 of 25 (56%) specimens, and 6 of 24 (25%) specimens, respectively. CONCLUSIONS: These results suggest that noncancerous lesions of the biliary epithelium in patients with pancreaticobiliary maljunction have mutations of the K- ras gene and/or the p53 gene, which provides genetic evidence that biliary epithelium has high carcinogenic potential.

Adult↗
PubMed1991

Overview: industrial perspectives on existing in vivo gene mutation assays.

In vivo gene mutation assays are considered the most definitive for the evaluation of human health risks. Suggestions are provided here for the critical evaluation of the application of established in vivo gene mutation assays and alternative approaches in the evaluation of industrial chemicals. Objective evaluation of the assays and approaches based on sound science and practical issues will allow better application of the existing assays. Such an evaluation may also help illuminate areas of improvement, as well as help guide the development of future assays.

Animals↗
PubMed2004

Long-term growth hormone therapy in adulthood results in significant linear growth in siblings with a PROP-1 gene mutation.

PROP-1 gene mutations result in impaired production of GH, gonadotropins, TSH, and prolactin. We describe three adult siblings, aged 18-25 yr, with short stature, hypothyroidism, and lack of pubertal maturation, who were homozygous for 301-302delAG PROP-1 mutation. We had the unique opportunity to treat them in adulthood with GH for 4-5 yr and thyroid replacement before sex steroid replacement. Sibling 1, a female, had a chronological age (CA) of 25 yr 8 months, a bone age (BA) of 12.5 yr, and height of 128.7 cm [-5.29 sd score (SDS)]; sibling 2, a younger sister had a CA of 22 yr 5 months, a BA of 13 yr, and height of 137.5 cm (-3.94 SDS); and sibling 3, a male, had a CA of 18 yr 4 months, a BA of 11.5 yr, and height of 127.5 cm (-6.38 SDS). Despite delay in treatment and fairly advanced BA, all responded to GH and thyroid hormone therapy with a dramatic increase in linear growth: 22.3 cm for sibling 1, 22 cm for sibling 2, and 34.5 cm for sibling 3. After sex hormone replacement, siblings 1, 2, and 3 grew another 2.6, 3, and 9.5 cm to final heights of 153.6, 162.5, and 171.5 cm, respectively. In conclusion, the substantial linear growth in adult siblings with a PROP-1 mutation illustrates that despite an advanced BA, linear growth potential remains in adulthood in the setting of sex steroid deficiency.

Adolescent↗
PubMed2002

Human gene mutations causing infertility.

The identification of gene mutations causing infertility in humans remains noticeably deficient at present. Although most males and females with infertility display normal pubertal development, nearly all of the gene mutations in humans have been characterised in people with deficient puberty and subsequent infertility. Gene mutations are arbitrarily categorised into four different compartments (I, hypothalamic; II, pituitary; III, gonadal; and IV, outflow tract). Diagnoses of infertility include hypogonadotrophic hypogonadism (compartments I and II), hypergonadotrophic hypogonadism (III), and obstructive disorders (compartment IV). Most gene mutations identified to date affect gonadal function, but it is also apparent that a large number of important genes in normal fertility have yet to be realised.

Chromosome Aberrations↗
PubMed1975

Mutator genes and selection for the mutation rate in bacteria.

Gene frequencies in populations of haploid, asexual organisms are described by linear recurrence equations. Several models in which the mutation rate is controlled by one locus and the fitness is controlled at one or more other loci are developed. It is shown that good approximations can be introduced to give explicit solutions for the course of selection in these models. It is shown that a strong non-equilibrium selection for mutator genes is possible even when the presence of such a gene decreases the fitness of an individual. Experiments that corroborate these conclusions are discussed along with the effects of population size that determine the applicability of these results to natural populations.

Alleles↗
PubMedDate not supplied

Electro-oculographic and electroretinographic studies in HNPCC gene mutation carriers.

PURPOSE: To assess retinal function in HNPCC gene mutation carriers. PATIENTS: 19 carriers (38 eyes) of HNPCC genes and controls. METHODS: Electro-oculogram, standard flash electroretinogram and pattern electroretinogram (PERG) recordings were performed. RESULTS: In the total group of HNPCC gene mutation carriers examined by oscillatory potentials, reduced amplitude (p < 0.0004) and increased latency (p < 0.04) of the O3 wave and increased latency (p < 0.02) of the O4 wave were found. In the subgroup of carriers with hMLH1 gene mutation, reduced amplitudes of the O3 (p < 0.0005) and O4 (p < 0.04) waves were identified. In the total group of HNPCC gene mutation carriers examined by PERG, reduced amplitudes of the P50 (p < 0.003), N95 (p < 0.02) and abnormal N95/P50 ratio (p < 0.02) were revealed. In the subgroup of hMLH1 gene mutation carriers, reduced amplitude of the P50 (p < 0.04) and abnormal N95/P50 ratio (p < 0.02) were observed, whereas in the hMSH2 gene mutation carrier subgroup, reduced amplitude (p < 0.03), shortened latency of the P50 wave (p < 0.02) and reduced amplitude of the N95 wave (p < 0.03) were found. CONCLUSION: Constitutional dysfunction of the inner retina appears to be a characteristic feature of HNPCC gene mutation carriers.

Adult↗
PubMed2001

Hereditary pancreatitis in Japan: a review of pancreatitis-associated gene mutations.

Pancreatitis-associated gene mutations have been reported in patients with hereditary pancreatitis and idiopathic pancreatitis in the Caucasian population and involve the cationic trypsinogen gene, the pancreatic secretory trypsin inhibitor gene and the cystic fibrosis transmembrane conductance regulator gene. In the Japanese population, mutational screening analyses of these genes have shown several mutations. The present study reviews previous reports from Japan in order to evaluate the racial specificity of pancreatitis-associated gene mutations.

Cystic Fibrosis Transmembrane Conductance Regulato↗
PubMed2005

Hemochromatosis gene mutations, body iron stores, dietary iron, and risk of colorectal adenoma in women.

BACKGROUND: Some experimental evidence suggests that iron may play a role in colorectal carcinogenesis, but human data for this role have been conflicting, possibly because of problems related to study design or measurement of iron exposure. We assessed dietary iron intake and genetic and biochemical markers of iron status in a prospective, nested case-control study of women enrolled in the Nurses' Health Study. METHODS: Among 32 826 women who provided a blood specimen, we identified 527 women with colorectal adenoma and 527 matched control subjects who underwent endoscopy but were not diagnosed with adenoma after blood collection. We assessed iron intake, mutations in the HFE gene that are associated with hereditary hemochromatosis (i.e., H63D and C282Y), and plasma biochemical measures of total body iron, including transferrin saturation and the ratio of the concentrations of transferrin receptors to ferritin. Logistic regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI). All statistical tests were two-sided. RESULTS: Women with any HFE gene mutation had higher total body iron stores, as reflected by higher transferrin saturations (P < .001) and lower levels of the ratio of transferrin receptors to ferritin (P = .02), than women with no HFE gene mutation. However, HFE gene mutations were not associated with risk of adenoma (multivariable RR = 1.08, 95% CI = 0.83 to 1.39; P = .58). Moreover, comparison of extreme categories showed no associations between adenoma and the extent of transferrin saturation (multivariable RR = 0.96, 95% CI = 0.63 to 1.47; Ptrend = .66), the ratio of transferrin receptors to ferritin (multivariable RR = 0.98, 95% CI, 0.60 to 1.60; Ptrend = .99), or dietary iron intake (multivariable RR = 1.04, 95% CI = 0.68 to 1.57; Ptrend = .94). CONCLUSIONS: Although our study used several distinct measures of iron status (i.e., genetic mutations, biochemical markers, and dietary intake) and a nested case-control design, we did not observe a role for iron in the pathogenesis of colorectal neoplasia in women.

Adenoma↗
PubMed2002

Radiosensitive SCID patients with Artemis gene mutations show a complete B-cell differentiation arrest at the pre-B-cell receptor checkpoint in bone marrow.

Severe combined immunodeficiency disease (SCID) can be immunologically classified by the absence or presence of T, B, and natural killer (NK) cells. About 30% of T(-)B(-)NK(+) SCID patients carry mutations in the recombination activating genes (RAG). Some T(-)B(-)NK(+) SCID patients without RAG gene mutations are sensitive to ionizing radiation, and several of these radiosensitive (RS) SCID patients were recently shown to have large deletions or truncation mutations in the Artemis gene, implying a role for Artemis in DNA double-strand break (dsb) repair. We identified 5 RS-SCID patients without RAG gene mutations, 4 of them with Artemis gene mutations. One patient had a large genomic deletion, but the other 3 patients carried simple missense mutations in conserved amino acid residues in the SNM1 homology domain of the Artemis protein. Extrachromosomal V(D)J recombination assays showed normal and precise signal joint formation, but inefficient coding joint formation in fibroblasts of these patients, which could be complemented by the wild-type Artemis gene. The cells containing the missense mutations in the SNM1 homology domain had the same recombination phenotype as the cells with the large deletion, indicating that these amino acid residues are indispensable for Artemis function. Immunogenotyping and immunophenotyping of bone marrow samples of 2 RS-SCID patients showed the absence of complete V(H)-J(H) gene rearrangements and consequently a complete B-cell differentiation arrest at the pre-B-cell receptor checkpoint-that is, at the transition from CyIgmu(-) pre-B-I cells to CyIgmu(+) pre-B-II cells. The completeness of this arrest illustrates the importance of Artemis at this stage of lymphoid differentiation.

Alternative Splicing↗