22q11 deletion in DGS/VCFS monozygotic twins with discordant phenotypes.
Genet Couns
; 10(1): 43-9, 1999.
Article
em En
| MEDLINE
| ID: mdl-10191428
ABSTRACT
22q11.2 deletion is a common genetic disorder characterised by a wide spectrum of clinical manifestations. To date no simple genotype-phenotype correlation has been established. Moreover, several reports have mentioned phenotypic discordance between monozygotic twins. No definite mechanism has been demonstrated and mosaicism, a postzygotic second hit, environmental effects and chance events have been proposed. The twinning process itself has been suspected in two cases (11, 23). We report the case of monozygous twins with a 22q11.2 deletion who are discordant for a heart defect. We found no arguments for mosaicism or twin-to-twin transfusion syndrome. The frequent discordance for heart defects in DiGeorge/Velo-cardio-facial syndromes (DGS/VCFS) does not favour the hypothesis of somatic mutations contributing to the phenotypic variation, but rather a complex interaction between genetic and environmental systems.
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Base de dados:
MEDLINE
Assunto principal:
Fenótipo
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Cromossomos Humanos Par 22
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Insuficiência Velofaríngea
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Deleção Cromossômica
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Síndrome de DiGeorge
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Doenças em Gêmeos
Idioma:
En
Ano de publicação:
1999
Tipo de documento:
Article