Dataset Information

Constitutional Mosaic Trisomy 13 in Two Germ Cell Layers is Different from Patau Syndrome? A Case Report.

ABSTRACT: The heterogeneous phenotype of known syndromes is a clinical challenge, and harmonized description using globally accepted ontology is desirable. This report attempts phenotypic analysis in a patient of constitutional mosaic trisomy 13 in mesoderm and ectoderm to make globally comparable clinical description. Phenotypic features (minor/major abnormalities) were recorded and matched with the Human Phenotype Ontology terms that were used to query web-based tool Phenomizer. We report here a case of 24-year-old girl born to non consanguineous parents with history of one abortion. Her phenotypic evaluation included short columella, low-set ears, seizures, enlarged naris, bifid tongue, infra-orbital fold, smooth philtrum, microtia, microcephaly, carious teeth, downslanted palpebral fissures, proportionate short stature, high palate, thin upper lip vermilion, small for gestational age, broad fingertip, broad hallux, mandibular prognathia and dental malocclusion. Karyotype and interphase FISH (Fluorescence in situ hybridization) was done in blood cells. Interphase FISH was also performed on buccal epithelial cells. Cytogenetic analysis demonstrated trisomy 13 mosaicism in 25% cells i.e. 47, XX,+13(9)/46,XX(27). The interphase FISH in blood cells showed trisomy 13 in 15%, whereas in buccal mucosa cells showed nearly 6%. Mosaic aneuploidy in constitutional karyotype can be responsible for variation in clinical and morphological presentation of patient with genetic disorder.

SUBMITTER: Kunwar F

PROVIDER: S-EPMC4843283 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

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Constitutional Mosaic Trisomy 13 in Two Germ Cell Layers is Different from Patau Syndrome? A Case Report.

Kunwar Fulesh F Pandya Vidhi V Bakshi Sonal R SR

Journal of clinical and diagnostic research : JCDR 20160301 3

The heterogeneous phenotype of known syndromes is a clinical challenge, and harmonized description using globally accepted ontology is desirable. This report attempts phenotypic analysis in a patient of constitutional mosaic trisomy 13 in mesoderm and ectoderm to make globally comparable clinical description. Phenotypic features (minor/major abnormalities) were recorded and matched with the Human Phenotype Ontology terms that were used to query web-based tool Phenomizer. We report here a case of ...[more]

PMID: 27134897

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Project description:Silencing of tumor suppressor genes by promoter hypermethylation is a key mechanism to facilitate cancer progression in many malignancies. While promoter hypermethylation can occur at later stages of the carcinogenesis process, constitutional methylation of key tumor suppressors may be an initiating event whereby cancer is started. Constitutional BRCA1 methylation due to cis-acting germline genetic variants is associated with a high risk of breast and ovarian cancer. However, this seems to be a rare event, restricted to a very limited number of families. In contrast, mosaic constitutional BRCA1 methylation is detected in 4-7% of newborn females without germline BRCA1 mutations. While the cause of such methylation is poorly understood, mosaic normal tissue BRCA1 methylation is associated with a 2-3 fold increased risk of high-grade serous ovarian cancer (HGSOC). As such, BRCA1 methylation may be the cause of a significant number of ovarian cancers. Given the molecular similarities between HGSOC and basal-like breast cancer, the findings with respect to HGSOC suggest that constitutional BRCA1 methylation could be a risk factor for basal-like breast cancer as well. Similar to BRCA1, some specific germline variants in MLH1 and MSH2 are associated with promoter methylation and a high risk of colorectal cancers in rare hereditary cases of the disease. However, as many as 15% of all colorectal cancers are of the microsatellite instability (MSI) "high" subtype, in which commonly the tumors harbor MLH1 hypermethylation. Constitutional mosaic methylation of MLH1 in normal tissues has been detected but not formally evaluated as a potential risk factor for incidental colorectal cancers. However, the findings with respect to BRCA1 in breast and ovarian cancer raises the question whether mosaic MLH1 methylation is a risk factor for MSI positive colorectal cancer as well. As for MGMT, a promoter variant is associated with elevated methylation across a panel of solid cancers, and MGMT promoter methylation may contribute to an elevated cancer risk in several of these malignancies. We hypothesize that constitutional mosaic promoter methylation of crucial tumor suppressors may trigger certain types of cancer, similar to germline mutations inactivating the same particular genes. Such constitutional methylation events may be a spark to ignite cancer development, and if associated with a significant cancer risk, screening for such epigenetic alterations could be part of cancer prevention programs to reduce cancer mortality in the future.

Dataset Information

Constitutional Mosaic Trisomy 13 in Two Germ Cell Layers is Different from Patau Syndrome? A Case Report.

Publications

Constitutional Mosaic Trisomy 13 in Two Germ Cell Layers is Different from Patau Syndrome? A Case Report.

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