Triple A syndrome is caused by mutations in AAAS, a new WD-repeat protein gene.
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The triple A syndrome (MIM 231550) is a rare autosomal recessive disorder characterized by adrenal insufficiency, achalasia and alacrima. The frequent association with a variety of neurological features may result in a severely disabling disease. We previously mapped the syndrome to a 6 cM interval on chromosome 12q13 and have now refined the critical region to 0 cM between KRT8 and D12S1651. Overlapping bacterial artificial chromosome (BAC) sequences of a high resolution BAC/P1-derived artificial chromosome (PAC) contig were screened for gene content and a novel gene encoding a 546 amino acid polypeptide was identified. In nine triple A syndrome patients eight different homozygous and compound heterozygous mutations were found in this gene, most of them leading to a truncated protein suggesting loss of function. RNA blotting experiments revealed marked expression in neuroendocrine and gastrointestinal structures, which are predominantly affected in triple A syndrome, supporting the hypothesis that mutations in this triple A syndrome gene (AAAS) are responsible for the disease. The predicted protein belongs to the family of WD repeat-containing proteins which exhibit a high degree of functional diversity including regulation of signal transduction, RNA processing and transcription. (+info)
IL-TIF/IL-22: genomic organization and mapping of the human and mouse genes.
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IL-TIF is a new cytokine originally identified as a gene induced by IL-9 in murine T lymphocytes, and showing 22% amino acid identity with IL-10. Here, we report the sequence and organization of the mouse and human IL-TIF genes, which both consist of 6 exons spreading over approximately 6 Kb. The IL-TIF gene is a single copy gene in humans, and is located on chromosome 12q15, at 90 Kb from the IFN gamma gene, and at 27 Kb from the AK155 gene, which codes for another IL-10-related cytokine. In the mouse, the IL-TIF gene is located on chromosome 10, also in the same region as the IFN gamma gene. Although it is a single copy gene in BALB/c and DBA/2 mice, the IL-TIF gene is duplicated in other strains such as C57Bl/6, FVB and 129. The two copies, which show 98% nucleotide identity in the coding region, were named IL-TIF alpha and IL-TIF beta. Beside single nucleotide variations, they differ by a 658 nucleotide deletion in IL-TIF beta, including the first non-coding exon and 603 nucleotides from the promoter. A DNA fragment corresponding to this deletion was sufficient to confer IL-9-regulated expression of a luciferase reporter plasmid, suggesting that the IL-TIF beta gene is either differentially regulated, or not expressed at all. (+info)
Copy number gain at 12q12-14 may be important in the transformation from follicular lymphoma to diffuse large B cell lymphoma.
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The purpose of this study was to identify novel areas of genomic copy number change associated with transformation from follicular lymphoma (FL) to diffuse large B cell lymphoma (DLBL). DNA was extracted from tumour cells micro-dissected from paraffin- embedded tissue sections in 24 patients with FL and subsequent transformation to DLBL and 18 patients with de novo DLBL. Tumour DNA was compared to reference DNA using comparative genomic hybridization. Abnormalities common to all 3 groups were gains on chromosomes 4q, 5q, 7q, 11q and X and losses on 3p, 8p and 10q. Copy number changes seen in both transformed and de novo DLBL and not seen in FL were gains on 2p and losses on 1q, 15q and Xq. Gains on 2q, 6p, 7p and 17q and losses on 5p and 8q were specific to transformed DLBL cases. Gain on 12q12-14 was found in 52% of the transformed DLBL cases and was never seen in its follicular counterpart. Patterns of genomic copy number change associated with specific clinical events in NHL have been demonstrated and suggest that gains on 2q, 6p, 7p, 12q and 17q and losses on 5p and 8q may be important in the transformation from low to high-grade disease. (+info)
Malignant melanoma is genetically distinct from clear cell sarcoma of tendons and aponeurosis (malignant melanoma of soft parts).
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Clear cell sarcoma of tendons and aponeuroses (malignant melanoma of soft parts) and conventional malignant melanoma may demonstrate significant morphologic overlap at the light microscopic and ultrastructural level. Consequently, the clinically relevant distinction between primary clear cell sarcoma and metastatic melanoma in the absence of a known primary cutaneous, mucosal or ocular tumour may occasionally cause diagnostic problems. A balanced translocation, t(12;22)(q13;q13), which can be detected, amongst others, using the reverse transcriptase polymerase chain reaction (RT-PCR) or fluorescent in situ hybridization (FISH), has been identified in a high percentage (50-75%) of clear cell sarcomas and is presumed to be tumour specific. Whether this chromosomal rearrangement is present in malignant melanoma has, to date, not as yet been studied by molecular genetic or molecular cytogenetic techniques. Using RT-PCR and FISH, a series of metastases from 25 known cutaneous melanomas and 8 melanoma cell lines (5 uveal and 3 cutaneous) were screened for the t(12;22)(q13;q13) translocation. Primers for RT-PCR were chosen based upon published breakpoint sequences. The Cosmids G9 and CCS2.2, corresponding to the 5' region of EWS and 3' region of ATF-1 respectively, were used as probes. The translocation was not identified in any of the melanomas or melanoma cell lines analysed in this study; in contrast this translocation was identified in 3 out of 5 clear cell sarcomas using these techniques. This allows distinction between translocation positive cases of clear cell sarcoma and malignant melanoma at a molecular genetic level. Consequently, in diagnostically challenging cases, this represents a valuable tool for the clinicopathologic differentiation between these two entities, with an important impact on patient management and prognosis. (+info)
Leiomyomata: heritability and cytogenetic studies.
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Leiomyomata represent the most common gynaecological tumour in women of reproductive age, and are the primary indication for hysterectomy in the USA. Cytogenetic and genetic studies have, in recent years, advanced our understanding of the aetiology of these tumours. Cytogenetic aberrations involving chromosomes 6, 7, 12 and 14 constitute the major chromosomal abnormalities seen in leiomyomata, and suggest the possibility that disruption or dysregulation of the genes HMGIC and HMGIY may contribute to the development of these tumours. Based on the finding of a variety of chromosomal aberrations detected in fibroids, other genes with fundamental roles in the pathobiology of uterine leiomyomata await identification. Furthermore, the incidence of fibroids has been shown to be greater in African-American women than in Caucasian women. The existence of a heritability component of uterine leiomyomata has been further implicated by twin-pair studies and the existence of familial forms of leiomyomata, both of which suggest an inherited diathesis for leiomyomata formation. This paper will review the cytogenetic aberrations and gene expression, with respect to their contributions to the pathogenesis of leiomyomata, and also summarize the current understanding of heritability of these tumours. (+info)
Sequential fluorescence in situ hybridization analyses for trisomy 12 in chronic leukemic B-cell disorders.
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BACKGROUND AND OBJECTIVES: Trisomy 12 is one of the most common chromosomal abnormalities in B-cell chronic lymphocytic leukemia (CLL). The aberration is readily detected by fluorescence in situ hybridization (FISH). There are only a few reports in which FISH analyses have been used to study the expansion of the trisomy 12 clone over time. DESIGN AND METHODS: Repeat FISH analyses were performed in 77 patients with a chronic leukemic B-cell disorder. The aim was to study the development of the trisomy 12 clone throughout the course of the disease, to measure the effect of therapy on the proportion of trisomic cells, and to relate the findings to the response to therapy. RESULTS: Fifty-eight of the 60 patients with no trisomy 12 at the initial test were consistently disomic for chromosome 12, while 2 patients seemingly acquired trisomy 12 during follow-up. Seventeen patients showed trisomy 12 at the first test. Expansion of the trisomy 12 clone was seen in all patients with a progressive lymphocytosis. In contrast to poor responders, patients responding well to chemotherapy showed a significant decrease in the proportion of CD19+ cells with trisomy 12. The effect of purine analogs in patients with trisomy 12 seemed inferior, both clinically and when studying the effect on the trisomic clone. INTERPRETATIONS AND CONCLUSIONS: There is a strong association between expansion of the trisomy 12 clone and progressive disease, both in treated and untreated patients. Conversely, reduction of the trisomic B-cell clone was linked to clinical response to chemotherapy. Acquisition of trisomy 12 remains a rare event. (+info)
Congenital-infantile fibrosarcoma. A clinicopathologic study of 10 cases and molecular detection of the ETV6-NTRK3 fusion transcripts using paraffin-embedded tissues.
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Congenital-infantile fibrosarcoma (CIFS) is a relatively indolent sarcoma that should be distinguished from more aggressive spindle cell sarcomas of childhood. CIFSs have been found to have a novel recurrent reciprocal translocation t(12;15)(p13;q25) resulting in the gene fusion ETV6-NTRK3 (ETS variant gene 6; neurotrophic tyrosine kinase receptor type 3). We studied immunohistochemical expression of NTRK3, and conducted a reverse transcription-polymerase chain reaction (RT-PCR) assay to detect the ETV6-NTRK3 fusion transcripts using archival formalin-fixed paraffin-embedded tissues from 10 CIFSs. Thirty-eight other spindle cell tumors were included as controls. The ETV6-NTRK3 fusion transcripts were identified in 7 (70%) of 10 CIFSs. Nucleotide sequence analysis showed that the fusion occurred between ETV6 exon 5 and NTRK3 exon 13. The 38 control tumors were negative for the fusion transcript. Immunohistochemically, CIFSs consistently expressed NTRK3. But the expression of NTRK3 also was observed in 22 of 38 control tumors. These results show the diagnostic usefulness of RT-PCR methods to detect ETV6-NTRK3 fusion transcripts in archival formalin-fixed paraffin-embedded tissue and the important role of NTRK3 in the development of CIFS, despite its being a protein of little importance in differential diagnosis. (+info)
Identification of proacrosin binding protein sp32 precursor as a human cancer/testis antigen.
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Serological expression cloning of antigens eliciting a humoral immune response to a syngeneic mouse sarcoma identified pem (mouse placenta and embryonic expression gene) as a new member of the cancer/testis family. To identify the human homologue of pem, mouse pem sequences and pem-related expressed sequence tags from human testis were used as PCR primers for amplification using human testis cDNA. However, rather than pem, another gene, designated OY-TES-1, was isolated and found to be the human homologue of proacrosin binding protein sp32 precursor originally identified in mouse, guinea pig, and pig. OY-TES-1 maps to chromosome 12p12-p13 and contains 10 exons. Southern blot analysis suggests the presence of two OY-TES-1-related genes in the human genome. In normal tissues, OY-TES-1 mRNA was expressed only in testis, whereas in malignant tissues, a variable proportion of a wide array of cancers, including bladder, breast, lung, liver, and colon cancers, expressed OY-TES-1. Serological survey of 362 cancer patients with a range of different cancers showed antibody to OY-TES-1 in 25 patients. No OY-TES-1 sera reactivity was found in 20 normal individuals. These findings indicate that OY-TES-1 is an additional member of the cancer/testis family of antigens and that OY-TES-1 is immunogenic in humans. (+info)