Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fanconi anemia is an inherited disease characterized by bone marrow failure, congenital malformations, and predisposition to cancer. The breast cancer susceptibility gene BRCA2 was recently found to be associated with Fanconi anemia complementation group D1 (FA-D1). We examined four kindreds afflicted with Fanconi anemia for the presence of germline BRCA2 mutations. One kindred, of Ashkenazi Jewish ancestry, had five members who were diagnosed with breast cancer and two cousins who were BRCA2*6174delT/C3069X compound heterozygotes and had Fanconi anemia and brain tumors. In another kindred of Ashkenazi Jewish and Lithuanian Catholic ancestry, a child with Fanconi anemia and a medulloblastoma was a BRCA2*6174delT/886delGT compound heterozygote. Two other kindreds each contained a Fanconi anemia-afflicted child who developed medulloblastoma; one child was of Latin American ancestry and a compound heterozygote for BRCA2*I2490T/ 5301insA and the other was African American and a compound heterozygote for BRCA2*Q3066X/E1308X. Median age of the Fanconi anemia-afflicted children at brain tumor diagnosis was 3.5 years. The co-occurrence of brain tumors, Fanconi anemia, and breast cancer observed in one of these kindreds constitutes a new syndromic association. Individuals who carry a germline BRCA2 mutation and who plan to have children with a partner of Ashkenazi Jewish descent should consider undergoing genetic counseling.
 ...
PMID:Shared genetic susceptibility to breast cancer, brain tumors, and Fanconi anemia. 1455 78

The clinical, cytogenetic, and molecular findings of 2 Fanconi anemia (FA) subtype D1 kindreds, initially identified through a young child with a solid tumor (medullobastoma, Wilms tumor), are described. Each kindred subsequently had a second affected child; one developed Wilms tumor followed by a medulloblastoma, and the other developed T-lineage acute lymphoblastic leukemia. Cytogenetic studies revealed an unusually high spontaneous chromosome aberration rate, contrasting with other FA subtypes. Molecular analysis revealed biallelic BRCA2/FANCD1 mutations. The patients did not exhibit bone marrow failure. Our studies suggest that the D1 subtype represents a severe end of the cytogenetic spectrum within FA, consistent with a critical downstream role of BRCA2 in the FA pathway. Furthermore, this FA subgroup may be preferentially associated with an increased predisposition to solid tumors in early childhood. Recognition of this constellation of findings has significant implications for medical management and genetic counseling of FA families.
 ...
PMID:Association of biallelic BRCA2/FANCD1 mutations with spontaneous chromosomal instability and solid tumors of childhood. 1467 Sep 28

The genome protection pathway that is defective in patients with Fanconi anemia (FA) is controlled by at least eight genes, including BRCA2. A key step in the pathway involves the monoubiquitylation of FANCD2, which critically depends on a multi-subunit nuclear 'core complex' of at least six FANC proteins (FANCA, -C, -E, -F, -G, and -L). Except for FANCL, which has WD40 repeats and a RING finger domain, no significant domain structure has so far been recognized in any of the core complex proteins. By using a homology search strategy comparing the human FANCG protein sequence with its ortholog sequences in Oryzias latipes (Japanese rice fish) and Danio rerio (zebrafish) we identified at least seven tetratricopeptide repeat motifs (TPRs) covering a major part of this protein. TPRs are degenerate 34-amino acid repeat motifs which function as scaffolds mediating protein-protein interactions, often found in multiprotein complexes. In four out of five TPR motifs tested (TPR1, -2, -5, and -6), targeted missense mutagenesis disrupting the motifs at the critical position 8 of each TPR caused complete or partial loss of FANCG function. Loss of function was evident from failure of the mutant proteins to complement the cellular FA phenotype in FA-G lymphoblasts, which was correlated with loss of binding to FANCA. Although the TPR4 mutant fully complemented the cells, it showed a reduced interaction with FANCA, suggesting that this TPR may also be of functional importance. The recognition of FANCG as a typical TPR protein predicts this protein to play a key role in the assembly and/or stabilization of the nuclear FA protein core complex.
 ...
PMID:Multiple TPR motifs characterize the Fanconi anemia FANCG protein. 1469 62

Monoubiquitination of FANCD2 is a key step in the DNA damage response pathway involving Fanconi anemia proteins and the breast cancer susceptibility gene products, BRCA1 and BRCA2. One critical unresolved issue is the identity of the ubiquitin ligase responsible for this reaction. Two proteins, BRCA1 and FANCL(PHF9), have been suggested to be this ligase. Here we found that FANCL, but not BRCA1, evolutionarily co-exists with FANCD2 in several species. Moreover, the proportion of FANCD2 in chromatin and nuclear matrix is drastically reduced in a cell line mutated in FANCL, but not in that mutated in BRCA1. This defective distribution of FANCD2 in the FANCL-mutant cell line is likely due to its defective monoubiquitination, because the monoubiquitinated FANCD2 preferentially associates with chromatin and nuclear matrix, whereas non-ubiquitinated FANCD2 largely resides in the soluble fraction. Our data support the notion that FANCL, but not BRCA1, is the likely ligase for FANCD2 monoubiquitination.
 ...
PMID:FANCL replaces BRCA1 as the likely ubiquitin ligase responsible for FANCD2 monoubiquitination. 1471 86

Patients with Fanconi anemia (FA) display a wide variety of defects including bone marrow failure and a high risk of developing cancer. Multiple Fanconi genes exist whose proteins form a complex that along with BRCA1 is important for the translocalization of FANCD2 to nuclear foci. With BRCA2 and RAD51, this complex is thought to have a role in the repair of DNA double strand breaks. The genetic basis of another form of Fanconi anemia--FANCD1, was recently identified as the result of biallelic inactivating mutations of the BRCA2 gene. Since carriers of germline BRCA2 gene mutations have an increased risk of developing pancreatic cancer, the FA pathway has been investigated as a tumor suppressor pathway in pancreatic cancer. Recently van der Heijden et al. identified FANCC and FANCG gene mutations in patients with young-onset pancreatic cancer. Here, we determined the role of germline FA gene mutations in kindred in which several family members had pancreatic cancer. Sequence analysis of 38 individuals with familial pancreatic cancer enrolled in the National Familial Pancreatic Tumor Registry (NFPTR) revealed previously identified polymorphisms within two exons and one intron of FANCC, and in three introns of FANCG. In addition, an unaffected relative from one family contained an exonic polymorphism within the FANCC gene. These and published data suggest the possibility that although germline and somatic mutations in FANCC and FANCG may contribute to the occurrence of pancreatic cancers, the pancreatic cancers that arise do so in an apparent sporadic fashion rather than with a phenotype of familial pancreatic cancer. FANCC and FANCG mutations may have low penetrance for the pancreatic cancer phenotype.
 ...
PMID:The genetics of FANCC and FANCG in familial pancreatic cancer. 1503 1

Fanconi anemia (FA) is an autosomal recessive chromosomal instability disorder caused by mutations in one of seven known genes (FANCA,C,D2,E,F,G and BRCA2). Mutations in the FANCA gene are the most prevalent, accounting for two-thirds of FA cases. Affected individuals have greatly increased risks of acute myeloid leukemia (AML). This raises the question as to whether inherited or acquired mutations in FA genes might be involved in the development of sporadic AML. Quantitative fluorescent PCR was used to screen archival DNA from sporadic AML cases for FANCA deletions, which account for 40% of FANCA mutations in FA homozygotes. Four heterozygous deletions were found in 101 samples screened, which is 35-fold higher than the expected population frequency for germline FANCA deletions (P<0.0001). Sequencing FANCA in the AML samples with FANCA deletions did not detect mutations in the second allele and there was no evidence of epigenetic silencing by hypermethylation. However, real-time quantitative PCR analysis in these samples showed reduced expression of FANCA compared to nondeleted AML samples and to controls. These findings suggest that gene deletions and reduced expression of FANCA may be involved in the promotion of genetic instability in a subset of cases of sporadic AML.
 ...
PMID:Deletion and reduced expression of the Fanconi anemia FANCA gene in sporadic acute myeloid leukemia. 1474 3

Biallelic mutations in BRCA2/FANCD1 were recently recognized as a rare cause of Fanconi anemia (FA). Using immunodetection with an antiserum directed against the carboxyterminus of the BRCA2 protein, we screened 38 lymphoid cell lines from FA patients whom we could not previously assign, via retroviral complementation analysis, to any of six known FA complementation groups (FA-A, -C, -D2, -E, -F, or -G). Three of these 38 cell lines lacked the 380-kDa BRCA2 signal on immunoblots. DNA sequencing showed biallelic compound and truncating mutations in two of the immuno-negative cell lines, whereas a monoallelic frameshift mutation and an amino acid substitution were detected in the third cell line. Our data show that less than 10% of unassigned FA cell lines harbor truncating mutations in BRCA2/FANCD1. This finding strongly suggests the existence of (an) additional, as yet unknown FA gene(s).
 ...
PMID:Screening Fanconi anemia lymphoid cell lines of non-A, C, D2, E, F, G subtypes for defects in BRCA2/FANCD1. 1500 64

The breast cancer susceptibility gene BRCA2 has recently been identified as identical to the Fanconi anemia (FA) gene FANCD1. Here we expand the clinical implications of this discovery. Notably, we identified 6 children in 5 kindreds exhibiting the co-occurrence of BRCA2 mutations, FA, and early onset acute leukemia. Leukemia occurred at a median of 2.2 years of age in the BRCA2 patients in contrast to a median onset of 13.4 years in all other FA patients in the International Fanconi Anemia Registry (IFAR; P <.0001). Breast cancer was noted in 4 of the 5 kindreds. Of the 6 children with leukemia, 4 were treated with bone marrow transplantation and 2 are alive at 3 and 9 months after treatment. Our results suggest that BRCA2 testing should be considered in all patients with FA in whom the complementation group cannot be defined or in whom leukemia is diagnosed at or before 5 years of age.
 ...
PMID:Germline mutations in BRCA2: shared genetic susceptibility to breast cancer, early onset leukemia, and Fanconi anemia. 1507 Jul 7

Fanconi anemia (FA) and cells lacking functional BRCA1 and BRCA2 proteins are hypersensitive to interstrand crosslinking (ICL) agents and show increased numbers of chromosomal breaks and radials. Although radial formation has been used to diagnose FA for more than 30 years, there has been little analysis of these characteristic formations. In this study, radials were analyzed from FA-A and FA-G fibroblasts as well as normal and retrovirally-corrected FA-A fibroblasts treated with high doses of ICLs. Radials were found to only involve non-homologous chromosome interactions and to be distributed nearly randomly along the length of chromosomes. Sites on chromosomes that did show increased frequency of radial involvement did not correlate with known fragile sites or pericentric regions. Hybrid radials were observed between mouse and human chromosomes in human-mouse hybrid cells produced by microcell-mediated chromosome transfer of mouse chromosomes into human FA-A fibroblasts. Both X and Y chromosomes were notably not involved in radials. These observations suggest that ICL repair may involve short stretches of homology, resulting in aberrant radial formation in the absence of FA proteins.
 ...
PMID:Interstrand crosslink-induced radials form between non-homologous chromosomes, but are absent in sex chromosomes. 1508 15

Fanconi anaemia (FA) is a chromosomal instability disorder characterized by cellular sensitivity to DNA interstrand crosslinking agents and a high risk of cancer. Six of the eight proteins encoded by the known FA genes form a nuclear complex which is required for the monoubiquitination of the FANCD2 protein. FANCD2 complexes and colocalizes with BRCA1, but its presumptive role in DNA repair has not yet been clearly defined. We used yeast two-hybrid analysis to test for interaction between FANCD2 and 10 proteins involved in homologous recombination repair. FANCD2 did not interact with RAD51, the five RAD51 paralogs, RAD52, RAD54 or DMC1. However, it bound to a highly conserved C-terminal site in BRCA2 that also binds FANCG/XRCC9. FANCD2 and BRCA2 can be coimmunoprecipitated from cell extracts of both human and Chinese hamster wild-type cells, thus confirming that the interaction occurs in vivo. Formation of nuclear foci of FANCD2 was normal in the BRCA2 mutant CAPAN-1 cells, which indicates that the recruitment of FANCD2 to sites of DNA-repair is independent of wild-type BRCA2 function. FANCD2 colocalized with RAD51 in foci following treatment with mitomycin C or hydroxyurea, and colocalized very tightly with PCNA after treatment with hydroxyurea. These findings suggest that FANCD2 may have a role in the cellular response to stalled replication forks or in the repair of replication-associated double-strand breaks, irrespective of the type of primary DNA lesion.
 ...
PMID:Direct interaction of FANCD2 with BRCA2 in DNA damage response pathways. 1511 58


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>