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At least 307 records · Page 17Linked to original sources
PubMed1998

Germline mutation of the multiple endocrine neoplasia type 1 (MEN1) gene in a family with primary hyperparathyroidism.

Familial primary hyperparathyroidism (FHP) is a rare hereditary disorder characterized by isolated parathyroid tumors without any other lesions related to multiple endocrine neoplasia (MEN). Primary hyperparathyroidism is usually expressed at an early age and is highly penetrated in MEN type 1 (MEN1), suggesting that some FHP may be a variant type or early stage of MEN1. The MEN1 gene has recently been cloned and its germline mutations have been considered to play an important role in the tumorigenesis of MEN1. We studied a Japanese family with primary hyperparathyroidism which included 4 patients. To investigate the possible relationship between primary hyperparathyroidism in this family and the MEN1 gene, we analyzed a proband for a germline mutation of the MEN1 gene in this study. We identified a novel heterozygous mutation (1350del3) at codon 414 in exon 9. Restriction digestion analysis revealed the same mutation pattern in his brother with hyperparathyroidism. These findings suggest that our patients may belong to a variant type of MEN1.

Adult↗
PubMed2000

Mosaicism in von Hippel-Lindau disease: lessons from kindreds with germline mutations identified in offspring with mosaic parents.

von Hippel-Lindau disease (VHL [MIM 193300]) is a heritable autosomal dominant multiple-neoplastic disorder with high penetrance. It is characterized by brain and spinal-cord hemangioblastomas, retinal angiomas, clear-cell renal carcinoma, neuroendocrine tumors and cysts of the pancreas, pheochromocytomas, endolymphatic-sac tumors, and papillary cystadenomas of the epididymis and broad ligament. Although most index cases have a positive family history of VHL, some do not and may represent de novo cases. Cases without a family history of VHL may or may not have a germline mutation in their VHL tumor-suppressor gene. We present two cases of VHL mosaicism. In each of two families, standard testing methods (Southern blot analysis and direct sequencing) identified the germline mutation in the VHL gene of the offspring, but not in their clinically affected parent. Additional methods of analysis of the affected parents' blood detected the VHL-gene mutation in a portion of their peripheral blood lymphocytes. In one case, detection of the deleted allele was by FISH, and, in the second case, the 3-bp deletion was detected by conformational sensitive gel electrophoresis and DNA sequencing of cloned genomic DNA. Mosaicism in VHL is important to search for and recognize when an individual without a family history of VHL has VHL. Patients diagnosed without family histories of the disease have been reported in as many as 23% of kindreds with VHL. Identification of individuals potentially mosaic for VHL will affect counseling of families, and these individuals should themselves be included in clinical screening programs for occult disease.

Adult↗
PubMed2003

BRCA1 and BRCA2 germline mutations in lymphoma patients.

Mutations in the BRCA1 and BRCA2 tumor suppressor genes are associated with an increased risk for breast and ovarian cancers as well as other types of malignancies. The observation of a germline BRCA1 mutation in an index case with a lymphoid neoplasm in the setting of a family history of breast cancer prompted us to explore the role of BRCA germline mutations as lymphoma susceptibility alleles. A panel of 286 DNA samples from Jewish lymphoma patients was analyzed for the three most frequent BRCA1 and BRCA2 germline mutations in those of Ashkenazi Jewish heritage, and compared to a cohort of 5010 DNA samples from healthy controls. Of the 286 cases, 2 patients carried a germline BRCA mutation; both were diagnosed at an early age with an intermediate grade non-Hodgkin's lymphoma. This data indicate that germline BRCA mutations are not associated with an increased risk for lymphoid malignancies.

Adult↗
PubMed2000

Lack of germline mutations in the preproglucagon gene region coding for glucagon-like peptide 1 in Type 2 diabetic (NIDDM) patients.

Glucagon-like peptide 1 (GLP-1) has antidiabetic effects and many facets of Type 2 diabetes could theoretically be the consequence of a reduction in or lack of GLP-1 function. Exogenous GLP-1 is exquisitely effective in Type 2 diabetic patients, making receptor defects unlikely. GLP-1 responses after meals as detected by radioimmunoassay are not overtly reduced in Type 2 diabetic patients. Therefore, a sequence analysis of exon 2 of the preproglucagon gene coding for the GLP-1 protein was initiated in order to exclude potential germline mutations. 24 Type 2 diabetic patients and in 14 control subjects with normal oral glucose tolerance (WHO criteria) were studied. In all specimens of peripheral blood leukocyte DNA examined, no germline mutations of the GLP-1 sequence were identified, thus excluding mutations in the GLP-1 sequence as a major contributor to the pathophysiological appearance of the Type 2 diabetic phenotype. Rare mutations, however, cannot be excluded due to the small number of Type 2 diabetic patients examined.

Aged↗
PubMed1998

ATM germline mutations in classical ataxia-telangiectasia patients in the Dutch population.

Germline mutations in the ATM gene are responsible for the autosomal recessive disorder ataxia-telangiectasia (A-T). In our study, we have determined the ATM mutation spectrum in 19 classical A-T patients, including some immigrant populations, as well as 12 of Dutch ethnic origin. Both the protein truncation test (PTT) and the restriction endonuclease fingerprinting (REF) method were used and compared for their detection efficiency, identifying 76% and 60% of the mutations, respectively. Most patients were found to be compound heterozygote. Seventeen mutations were distinct, of which 10 were not reported previously. Mutations are small deletions or point mutations frequently affecting splice sites. Moreover, a 16.7-kb genomic deletion of the 3' end of the gene, most likely a result of recombination between two LINE elements, was identified. The most frequently found mutation, identified in three unrelated Turkish A-T individuals, was previously described to be a Turkish A-T founder mutation. The presence of a founder mutation among relatively small ethnic population groups in Western Europe could indicate a high carrier frequency in such communities. In patients of Dutch ethnic origin, however, no significant founder effect could be identified. The observed genetic heterogeneity including the relative high percentage of splice-site mutations had no reflection on the phenotype. All patients manifested classical A-T and increased cellular radioresistant DNA synthesis.

Ataxia Telangiectasia↗
PubMed2000

Individuals with presumably hereditary uveal melanoma do not harbour germline mutations in the coding regions of either the P16INK4A, P14ARF or cdk4 genes.

In familial cutaneous malignant melanoma (CMM), disruption of the retinoblastoma (pRB) pathway frequently occurs through inactivating mutations in the p16 (p16INK4A/CDKN2A/MTS1) gene or activating mutations in the G1-specific cyclin dependent kinase 4 gene (CDK4). Uveal malignant melanoma (UMM) also occurs in a familial setting, or sometimes in association with familial or sporadic CMM. Molecular studies of sporadic UMM have revealed somatic deletions covering the INK4A-ARF locus (encoding P16INK4A and P14ARF) in a large proportion of tumours. We hypothesized that germline mutations in the p16INK4A, p14ARF or CDK4 genes might contribute to some cases of familial UMM, or to some cases of UMM associated with another melanoma. Out of 155 patients treated at the Institut Curie for UMM between 1994 and 1997, and interviewed about their personal and familial history of melanoma, we identified seven patients with a relative affected with UMM (n = 6) or CMM (n = 1), and two patients who have had, in addition to UMM, a personal history of second melanoma, UMM (n = 1), or CMM (n = 1). We screened by polymerase chain reaction single-strand conformation polymorphism the entire coding sequence of the INK4A-ARF locus (exon 1alpha from p16INK4A, exon 1beta from p14ARF, and exons 2 and 3, common to both genes), as well as the exons 2, 5 and 8 of the CDK4 gene, coding for the functional domains involved in p16 and/or cyclin D1 binding. A previously reported polymorphism in exon 3 of the INK4A-ARF locus was found in one patient affected with bilateral UMM, but no germline mutations were detected, either in the p16INK4A, p14ARF or CDK4 genes. Our data support the involvement of other genes in predisposition to uveal melanoma.

Adult↗
PubMed2002

Two percent of men with early-onset prostate cancer harbor germline mutations in the BRCA2 gene.

Studies of families with breast cancer have indicated that male carriers of BRCA2 mutations are at increased risk of prostate cancer, particularly at an early age. To evaluate the contribution of BRCA2 mutations to early-onset prostate cancer, we screened the complete coding sequence of BRCA2 for germline mutations, in 263 men with diagnoses of prostate cancer who were </=55 years of age. Protein-truncating mutations were found in six men (2.3%; 95% confidence interval 0.8%-5.0%), and all of these mutations were clustered outside the ovarian-cancer cluster region. The relative risk of developing prostate cancer by age 56 years from a deleterious germline BRCA2 mutation was 23-fold. Four of the patients with mutations did not have a family history of breast or ovarian cancer. Twenty-two variants of uncertain significance were also identified. These results confirm that BRCA2 is a high-risk prostate-cancer-susceptibility gene and have potential implications for the management of early-onset prostate cancer, in both patients and their relatives.

Adult↗
PubMed2005

[Germline mutations of tetranucleotide DNA repeats in families with normal children and reproductive pathology].

We have previously reported a high rate of tetranucleotide DNA repeat mutations, including mutations of both germline and somatic origin, in spontaneous human abortuses. To analyze in more detail mutational microsatellite (MS) variability in meiosis and its possible association with disturbed embryonic development, we have conducted a comparative study of mutation rates of a complex of 15 autosomal tetranucleotide MSs in 55 families with healthy children and in 103 families that have had spontaneous abortuses with normal karyotypes. In the families with miscarriage, the gametic MS mutation rate was higher than in the families with normal reproductive function (4.36 x 10(-3) versus 2.32 x 10(-3) per locus per gamete per generation), but this difference was statistically nonsignificant (P = 0.25). No association of MS mutations with familiar miscarriage was found. Mutations at the MS loci studied were recorded almost 3 times as often in spermatogenesis as in oogenesis, which is likely to result from a greater number of DNA replication cycles in male germline cell precursors than in female ones. Mutations increasing and reducing the MS sequence length appeared at virtually the same rate. Changes in MS DNA sequence length per one repeated element, i.e., single-step mutations (93% of cases) exceeded all other events of allele length change. The highest number of mutations (81.2%) was found in longer alleles. This distribution of mutations by size, direction, and parental origin corresponds to the multistep mutation model of their emergence via mechanism of DNA strand slippage during replication.

Abortion, Habitual↗
PubMed2006

Expression and functional analysis of menin in a multiple endocrine neoplasia type 1 (MEN1) patient with somatic loss of heterozygosity in chromosome 11q13 and unidentified germline mutation of the MEN1 gene.

In some patients with multiple endocrine neoplasia type 1 (MEN1) it is not possible to identify a germline mutation in the MEN1 gene. We sought to document the loss of expression and function of the MEN1 gene product, menin, in the tumors of such a patient. The proband is an elderly female patient with primary hyperparathyroidism, pancreatic islet tumor, and breast cancer. Her son has primary hyperparathyroidism. No germline MEN1 mutation was identified in the proband or her son. However, loss of heterozygosity at the MEN1 locus and complete lack of menin expression were demonstrated in the proband's tumor tissue. The proband's cultured parathyroid cells lacked the normal reduction in proliferation and parathyroid hormone secretion in response to transforming growth factor- beta. This assessment provided insight into the molecular pathogenesis of the patient and provides evidence for a critical requirement for menin in the antiproliferative action of transforming growth factor-beta.

Aged↗
PubMed2003

A novel Q3034R BRCA2 germline mutation identified in a fallopian tube cancer patient.

Fallopian tube cancer (FTC) accounts for 0.1-0.5% of all gynaecological malignancies, so that very few studies have demonstrated a significant linkage between this cancer type and BRCA1/BRCA2 mutations. We report the identification of a novel germline mutation (Q3034R) in BRCA2 gene in a 41-year-old patient. The nucleotide change (CAG > CGG) abolishes a DdeI restriction site, making genotype identification rapid and inexpensive. Our findings support the hypothesis that the primary FTC should be considered, at least in a subset of patients, as a BRCA2-associated tumor. Genetic counselling could result, in these cases, in early diagnosis of genetically predisposed individuals.

Adult↗
PubMed2005

Germline mutations in HRAS proto-oncogene cause Costello syndrome.

Costello syndrome is a multiple congenital anomaly and mental retardation syndrome characterized by coarse face, loose skin, cardiomyopathy and predisposition to tumors. We identified four heterozygous de novo mutations of HRAS in 12 of 13 affected individuals, all of which were previously reported as somatic and oncogenic mutations in various tumors. Our observations suggest that germline mutations in HRAS perturb human development and increase susceptibility to tumors.

Abnormalities, Multiple↗
PubMed1994

Novel germline mutation of the p53 tumor suppressor gene in a child with incidentally discovered adrenal cortical carcinoma.

PURPOSE: We report a case of adrenal cortical carcinoma in an infant, which was incidentally discovered by renal sonography after a urinary tract infection. The previous death of a sibling after rhabdomyosarcoma in infancy prompted a search for a heritable p53 tumor suppressor gene mutation in this family. PATIENTS AND METHODS: Starting with frozen adrenal carcinoma tissue, polymerase chain reaction (PCR) amplification followed by direct sequencing of exons 4-8 of p53 was used to search for a mutation. When a mutation was identified in exon 6 of the tumor p53 sequence, PCR amplification and direct sequencing of exon 6 alone was then performed on DNA from peripheral blood lymphocytes (PBLs) of all immediate family members to determine whether a germline mutation was present. A different set of primers was used by a second laboratory at our institution to independently confirm the presence of the mutation in the adrenal carcinoma and in paraffin-embedded rhabdomyosarcoma tissue of the deceased sibling. RESULTS: A C-to-T transition was identified at a CpG site in codon 196 resulting in a change from arginine to a stop codon (CGA to TGA). The identical mutation, present as the sole p53 allele in the tumor DNA samples and in the heterozygous state with wild type p53 allele in DNA from PBLs (germline), was found in the adrenal carcinoma, the rhabdomyosarcoma, and the PBLs of the tumor-bearing child and her healthy father and 5-year-old brother. This nonsense mutation of p53 has never before been reported in the germline. The extended pedigree showed only one known additional cancer. CONCLUSIONS: A novel germline p53 mutation was identified by investigation of a sibling pair with cancers associated with the Li-Fraumeni syndrome in a family with an otherwise negative history for cancer. The implications of this case for identification of carriers of p53 germline mutations and their clinical management are discussed.

Adrenal Cortex Neoplasms↗
PubMed1997

Germline mutations of the PTEN gene in Cowden disease, an inherited breast and thyroid cancer syndrome.

Cowden disease (CD) is an autosomal dominant cancer predisposition syndrome associated with an elevated risk for tumours of the breast, thyroid and skin. Lhermitte-Duclos disease (LDD) cosegregates with a subset of CD families and is associated with macrocephaly, ataxia and dysplastic cerebellar gangliocytomatosis. The common feature of these diseases is a predisposition to hamartomas, benign tumours containing differentiated but disorganized cells indigenous to the tissue of origin. Linkage analysis has determined that a single locus within chromosome 10q23 is likely to be responsible for both of these diseases. A candidate tumour suppressor gene (PTEN) within this region is mutated in sporadic brain, breast and prostate cancer. Another group has independently isolated the same gene, termed MMAC1, and also found somatic mutations throughout the gene in advanced sporadic cancers. Mutational analysis of PTEN in CD kindreds has identified germline mutations in four of five families. We found nonsense and missense mutations that are predicted to disrupt the protein tyrosine/dual-specificity phosphatase domain of this gene. Thus, PTEN appears to behave as a tumour suppressor gene in the germline. Our data also imply that PTEN may play a role in organizing the relationship of different cell types within an organ during development.

Breast Neoplasms↗
PubMed2002

APC germline mutations identified in Czech patients with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited predisposition to colorectal cancer, which is caused by germline mutations in the adenomatous polyposis coli (APC) gene. The APC mutations have been investigated in 46 Czech unrelated FAP families and 9 suspected FAP families using DGGE analysis and direct DNA sequencing. We found 25 germline APC mutations and identified 11 which were not previously reported. Of the identified mutations, 10 were 1 to 5 bp deletions, four were 1 bp insertions and six were nonsense, all leading to the formation of premature stop codon. In addition, we detected two mutations in the splice-donor region of APC intron 11, one missense and two samesense mutations. Phenotypes of patients with known and novel types of mutations are presented and discussed.

Adenomatous Polyposis Coli↗
PubMed2004

Familial melanoma, pancreatic cancer and germline CDKN2A mutations.

Germline CDKN2A mutations have been observed in approximately 20 percent of familial melanoma kindreds from North America, Europe and Australasia. There is also an increased risk of pancreatic cancer in a subset of families with mutations, however, the precise relationship between the CDKN2A gene and pancreatic cancer remains unknown. The relationships between familial melanoma, pancreatic cancer and germline CDKN2A mutations were examined using published data. There were 67 different CDKN2A mutations in 189 melanoma-prone families. Forty-two families (18 mutations) had pancreatic cancer reported. For families without reported pancreatic cancer, the most common types of mutations were missense (56%), frameshift (12%), and deletions (12%). For families with pancreatic cancer, missense (56%), splicing (17%), and frameshift (11%) mutations were most common. Seventy percent of the mutations were observed only once, while the remainder recurred in different families. Comparison of 147 melanoma-prone families without pancreatic cancer to the 42 families that had pancreatic cancer reported showed no significant differences in the types or locations of mutations. However, there was a significant difference (p=0.002) in the distribution of families across the four ankyrin repeats. This finding primarily resulted from the six most frequent mutations where the distribution of pancreatic cancer varied significantly (p=0.02) from at least 30% in c.301G>T (p.G101W), c.225_243del19 (p.P75fs), c.337_338insGTC (p.R112_L113insR), and c.377T>A (p.V126D) families to less than 10% in c.71G>C (p.R24P) and c.159G>C (p.M53I) families. Further research utilizing individual-specific data will be required to determine whether these patterns represent etiologic differences or incomplete reporting of cancer and mutation data.

Genes, p16↗
PubMedDate not supplied

BRCA1 germline mutations in Cypriot breast cancer patients from 26 families with family history.

Germline mutations in the BRCA1 gene are causative for a variable number of hereditary breast/ovarian cancers. The data presented in this study are based on genetic analysis of the BRCA1 gene in 49 DNA samples from breast cancer patients with a positive family history. A combination of manual direct DNA sequencing and SSCP analysis was used to screen the entire coding region of BRCA1. Overall 13 variants were detected which included 5 missense mutations, 3 polymorphisms and 5 intronic changes. Further genetic analysis of the 13 variants was carried out using 50 control DNA samples. Our results showed that 12 out of the 13 variants detected in the DNA of the patients group, were also present in the control group. It appears that the Greek Cypriot families studied so far have an unexpectebly low frequency of deleterious mutations in the BRCA1 gene. This is the first report on BRCA1 mutation analysis in Cyprus.

Adult↗
PubMed2002

Biallelic germline mutations in MYH predispose to multiple colorectal adenoma and somatic G:C-->T:A mutations.

We have recently demonstrated that inherited defects of the base excision repair gene MYH predispose to multiple colorectal adenomas and carcinoma. Three affected siblings from a single British family were identified as Y165C/G382D compound heterozygotes and both missense mutations were shown to be functionally compromised. Here, we report the identification of seven further unrelated patients with >100 colorectal adenomas (six with colorectal cancer) and biallelic germline mutations in MYH: four were homozygous for truncating mutations, two were homozygous for Y165C and one was a Y165C/G382D compound heterozygote. As predicted from studies of the bacterial and yeast orthologues of MYH, colorectal tumours from affected individuals displayed a significant excess of somatic G:C-->T:A mutations in APC, as compared to sporadic ( chi(2)=242.96, P<10(-20)) or FAP-associated ( chi(2)=194.85, P<10(-20)) colorectal tumours. The sequence immediately downstream of the somatic G:C-->T:A mutations was predominantly AA, irrespective of the nature of the germline MYH mutations. These findings confirm the role of MYH in colorectal adenoma and carcinoma predisposition.

Adenoma↗
PubMed1999

The type of somatic mutation at APC in familial adenomatous polyposis is determined by the site of the germline mutation: a new facet to Knudson's 'two-hit' hypothesis.

APC is often cited as a prime example of a tumor suppressor gene. Truncating germline and somatic mutations (or, infrequently, allelic loss) occur in tumors in FAP (familial adenomatous polyposis). Most sporadic colorectal cancers also have two APC mutations. Clues from attenuated polyposis, missense germline variants with mild disease and the somatic mutation cluster region (codons 1,250-1,450) indicate, however, that APC mutations might not result in simple loss of protein function. We have found that FAP patients with germline APC mutations within a small region (codons 1,194-1,392 at most) mainly show allelic loss in their colorectal adenomas, in contrast to other FAP patients, whose 'second hits' tend to occur by truncating mutations in the mutation cluster region. Our results indicate that different APC mutations provide cells with different selective advantages, with mutations close to codon 1,300 providing the greatest advantage. Allelic loss is selected strongly in cells with one mutation near codon 1,300. A different germline-somatic APC mutation association exists in FAP desmoids. APC is not, therefore, a classical tumor suppressor. Our findings also indicate a new mechanism for disease severity: if a broader spectrum of mutations is selected in tumors, the somatic mutation rate is effectively higher and more tumors grow.

Adenoma↗