Presence of harmless small supernumerary marker chromosomes hampers molecular genetic diagnosis: a case report
| Autor: | Nikolai Rubtsov, Martina Merkas, Ahmed B. Hamid, Thomas Liehr, Alma Küchler, Isolde Schreyer, Ferdinand von Eggeling, Raimund Fahsold, Jasen Anderson, Nadezda Kosyakova, Kristin Mrasek, Julia Hentschel, Elisabeth Ewers, Heike Nelle, Anikó Ujfalusi, Anja Weise |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Genetics
Cancer Research Pathology medicine.medical_specialty Heterochromatin small supernumerary marker chromosomes fragile X-syndrome unclear mental retardation Orvostudományok Biology medicine.disease Klinikai orvostudományok Biochemistry Phenotype Uniparental disomy Fragile X syndrome Oncology medicine Molecular Medicine Supernumerary Clinical case Genetic diagnosis Molecular Biology Small supernumerary marker chromosome |
| Popis: | Mental retardation is correlated in approximately 0.4% of cases with the presence of a small supernumerary marker chromosome (sSMC). However, here we report a case of a carrier of a heterochromatic harmless sSMC with fragile X syndrome (Fra X). In approximately 2% of sSMC cases, similar heterochromatic sSMC were observed in a clinically abnormal carriers. In a subset of such cases, uniparental disomy (UPD) of the corresponding sister chromosomes was shown to be the cause of mental retardation. For the remainder of the cases, including the present one, the sSMC was just a random finding not related to the clinical phenotype. Thus, it is proposed to test patients with heterochromatic sSMC and mental retardation of unclear cause as follows: i) exclude UPD, ii) test for Fra X as it is a major cause of inherited mental retardation, and iii) perform chip-based assays or tests for special genetic diseases according to the phenotype. In any case, the diagnosis of a cytogenetic aberration such as an sSMC should not automatically be considered the resolution of a clinical case. |
| Databáze: | OpenAIRE |
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