title: Monozygotic twins concordant for Cayler syndrome.
abstract: Deletions within chromosome band 22q11.2 are associated with a variety of conditions, although a simple genotype-phenotype correlation has not been established so far. Environmental factors, chance events, or a second hit theory were supported by two observations of monozygotic twins with 22q11.2 deletions and discordant phenotypes [Goodship et al., J Med Genet 1995;32:746-748; Fryer, J Med Genet 1996;33:173]. We present monozygotic twins concordant for 22q11.2 deletion and Cayler syndrome, favoring the view that there exists a predominant genetic determination of the del 22q11.2 phenotype. As these twins are diamniotic and dichorionic, they may offer a more reliable insight in genetic phenotype determination than the other published, probably monochorionic, twins who may have a discordant malformation by twinning itself.
authors.affiliation: Institute of Human Genetics, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Rauch
authors.forename: M
authors.initials: M
authors.lastname: Hofbeck
authors.forename: S
authors.initials: S
authors.lastname: Bähring
authors.forename: G
authors.initials: G
authors.lastname: Leipold
authors.forename: U
authors.initials: U
authors.lastname: Trautmann
authors.forename: H
authors.initials: H
authors.lastname: Singer
authors.forename: R A
authors.initials: RA
authors.lastname: Pfeiffer
mesh_terms: D002892:Chromosomes, Human, Pair 22 / Q000648:ultrastructure; D003448:Crying; D005146:Facial Asymmetry / Q000235:genetics*; D006330:Heart Defects, Congenital / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013577:Syndrome; D014430:Twins, Monozygotic / Q000235:genetics*