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Biomedical subjects

H Brauch

Publications and source records attributed to H Brauch.

At least 37 records · Page 2Linked to original sources
PubMed1996

Mutations in the VHL tumor suppressor gene and associated lesions in families with von Hippel-Lindau disease from central Europe.

von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome predisposing to retinal, cerebellar and spinal hemangioblastoma, renal cell carcinoma (RCC), pheochromocytoma and pancreatic tumors. Clinically two types of the disease can be distinguished: VHL type 1 (without pheochromocytoma) and VHL type 2 (with pheochromocytoma). We report VHL germline mutations and trends in phenotypic variation in families from central Europe. We identified 28 mutations in 53/65 (81.5%) families with 18 (64%) mutations being unique to this population. Whereas types and distribution of mutations as well as a strong correlation of missense mutations with the VHL 2 phenotype were similar to those identified in other populations, these families have provided new insights into the molecular basis for variability in the VHL 2 phenotype. Seven different missense mutations in exons 1 and 3 varied in their biological consequences from a minimal VHL 2 phenotype with pheochromocytoma only to a full VHL 2 phenotype with RCC and pancreatic lesion. These findings contribute to a better understanding of the fundamental mechanisms of VHL disease and its phenotypic variability. Further, we have provided rapid VHL screening for the families in central Europe, which has resulted in improved diagnosis and clinical management.

Base Sequence↗
PubMed1996

Monogenetic hypertension and pheochromocytoma.

Hypertension attributable to pheochromocytoma is a very attractive model for the elucidation of the pathogenesis of hypertension. Sixteen different point mutations in the RET proto-oncogene and 30 mutations in the Von Hippel-Lindau (VHL) tumor suppressor gene have been identified so far associated with expression of pheochromocytoma. Each of these mutations initiates either the syndrome of multiple endocrine neoplasia type 2 (MEN 2) (MEN 2A and MEN 2B) or the VHL disease. Certain mutations in both genes are associated with the presence of pheochromocytoma. In general, these pheochromocytomas produce catecholamines that result in hypertension. Therefore, analysis for germline mutations in these genes are of practical value, because susceptibility to these diseases can be predicted in as yet clinically unaffected relatives.

Genes, Tumor Suppressor↗
PubMed1995

Consequences of direct genetic testing for germline mutations in the clinical management of families with multiple endocrine neoplasia, type II.

OBJECTIVE: Multiple endocrine neoplasia, type II (MEN-II) is an autosomal dominant disorder characterized by tumors of thyroid C cells and pheochromocytoma. Recently, germline mutations in the RET proto-oncogene have been identified in patients with MEN-II. The aims of this study were (1) to define the mutations in clinically diagnosed MEN-II families, (2) to compare the results of genetic and biochemical testing, and (3) to evaluate the impact of mutation analyses for the members of these families. DESIGN: Register-based survey study of clinically affected and unaffected members of MEN-II families. SETTING: Register of families from Germany and Spain with pheochromocytomas. Two research laboratories at Cambridge University in the United Kingdom. PATIENTS: We investigated consenting affected and unaffected members belonging to a series of 10 families who met the clinical criteria for MEN-II. MAIN OUTCOME MEASURES: (1) Presence or absence of germline mutation in the RET proto-oncogene in affected and unaffected members of the 10 families, and (2) in the absence of RET mutation in a given family, presence or absence of germline mutation in the von Hippel-Lindau (VHL) gene, which is the susceptibility gene involved in a closely related syndrome, von Hippel-Lindau disease. RESULTS: In eight of these families, RET mutations were identified. The specific mutations were detected in all affected members. The remaining two families without RET mutations were subsequently shown to have a mutation within the VHL gene. The VHL mutations were identified in both families and represent a previously undescribed base change. After identification of the mutation, premorbid genetic testing was performed in all MEN-II and VHL families, resulting in detection of asymptomatic carriers in the MEN-II families. Clinically, the two VHL families differed from the eight MEN-II families by the presence of a C-cell tumor in only one individual from each family and extra-adrenal pheochromocytoma in three of nine affected individuals in the two families combined. CONCLUSIONS: The diagnosis of MEN-II should be confirmed by molecular genetic analysis and the diagnosis of VHL syndrome should be considered for families with an absence of RET mutations and a preponderance of pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed1995

Von Hippel-Lindau (VHL) disease with pheochromocytoma in the Black Forest region of Germany: evidence for a founder effect.

We identified a germline missense mutation at nucleotide 505 (T to C) of the VHL tumor suppressor gene in 14, apparently unrelated, VHL type 2A families from the Black Forest region of Germany. This mutation was previously identified in two VHL 2A families living in Pennsylvania (USA). All affected individuals in the 16 families shared the same VHL haplotype indicating a founder effect. This missense mutation at codon 169 (Tyr to His) would probably cause an alteration in the structure of the putative VHL protein. The association of this distinct mutation with the pheochromocytoma phenotype in VHL may help to elucidate the genetic mechanism of carcinogenesis in this multi tumor cancer syndrome.

Adrenal Gland Neoplasms↗
PubMed1995

[Hippel-Lindau syndrome and sporadic renal cell carcinomas. Pathogenesis, morphologic spectrum and molecular genetics].

von Hippel-Lindau (VHL) disease is an autosomal dominant heritable disease that often occurs in association with various benign and malignant tumours. Clinically the disease is classified as VHL 1 (without phaeochromocytoma) and VHL 2 (with phaeochromocytoma). Genetically, VHL is caused by germline mutations in the VHL tumour suppressor gene. More than 100 germline mutations and rearrangements have been identified, but the biological function of a hypothetical VHL protein is not yet known. Genotype-phenotype correlations should aid in the understanding of this biological role. All VHL manifestations subsequently develop to VHL mutations, but some mutations may act in a tissue-specific manner. Whereas missense mutations cause tumour suppression to fail in adrenal cells, more severe structural mutations are usually necessary for tumour development in renal cells. As predicted by the tumour suppressor theory, the VHL gene also plays a critical part in the pathogenesis of sporadic non-VHL-associated tumours. In a large number of sporadic renal clear cell carcinomas, mutations and hypermethylation cause inactivation of the VHL gene. Together with allelic 3p loss, these constitute rate-limiting events in renal tumourigenesis. Insights into the molecular basis of phenotypic variability in VHL disease and the confirmation of the tumour-suppressor criteria in VHL and non-VHL sporadic tumours indicate an important role of the VHL gene in the development of these tumours.

Adrenal Gland Neoplasms↗
PubMed1995

Microsatellite instability in adenocarcinomas of the upper gastrointestinal tract. Relation to clinicopathological data and family history.

We analyzed 66 adenocarcinomas arising in the upper gastrointestinal tract for microsatellite instability at eight microsatellite loci to investigate the role of these genetic alterations in the etiology of these tumors. We identified alterations in at least one locus in 11/46 adenocarcinomas of the stomach, in 2/15 adenocarcinomas arising in Barrett's esophagus, and in 1/5 adenocarcinomas of the duodenum and jejunum. Microsatellite instability in gastric tumors was found in 5/22 of intestinal, 1/3 of mixed, and 5/21 of diffuse type tumors. No relationship to the tumor stage (TNM), age, and survival time of the patients was observed. One patient had two synchronous gastric tumors both exhibiting microsatellite instability at multiple loci. His family history revealed four individuals in the maternal line afflicted with gastric carcinoma in three generations. Our data show that microsatellite instability is a genetic event in 11 to 24% of tumors of the upper gastrointestinal tract. The observation of microsatellite instability and a familial clustering of gastric tumors may suggest a genetic predisposition for a subset of gastric tumors, which may be identified by microsatellite analysis.

Adenocarcinoma↗
PubMed1994

Genetic alterations in sporadic renal-cell carcinoma: molecular analyses of tumor suppressor gene harboring chromosomal regions 3p, 5q, and 17p.

On a genetic level, renal-cell carcinoma has been characterized by an abnormality on the short arm of chromosome 3 (3p), which suggests the inactivation of a tumor suppressor gene. One tumor suppressor gene at 3p, the von Hippel-Lindau disease gene, is implicated in tumor development of a whole spectrum of hereditary neoplasms, including renal-cell carcinoma. It is not clear whether the same tumor suppressor gene accounts for all, i.e., hereditary and sporadic, renal-cell carcinomas. Analysis of 28 patients with sporadic renal-cell carcinomas for loss of heterozygosity was performed at chromosomal regions that contain known tumor suppressor genes so as to assess their potential involvement during renal tumorigenesis. We focused on chromosome 3p because it contains the von Hippel-Lindau (VHL) disease gene, on 5q because it harbors tumor suppressor genes involved in colorectal carcinoma, and on 17p because it includes a tumor suppressor gene involved in breast, colon, and lung carcinoma. Loss of alleles at 3p affected 96% of the evaluable patients, with frequencies being highest in the VHL region in 3p25-26 and at loci in 3p21. These data confirm the importance of a 3p defect early during tumorigenesis; however, the question as to the existence of a second renal-cell carcinoma gene remains unresolved. Changes at 5q were 53% and those at 17p were 35%, suggesting that these loci may not contribute to the initiation of the disease but rather may represent accumulating genetic defects associated with progression and malignancy.

Alleles↗