title: First patient with trisomy 21 accompanied by an additional der(4)(:p11 --> q11:) plus partial uniparental disomy 4p15-16.
abstract: We report on a rare additional numerical chromosomal aberration in a child with Down syndrome due to free trisomy 21. The karyotype showed 48,XY,+21,+mar after GTG banding, with the marker present in 80% of cells. The supernumerary marker chromosome (SMC) was as small as approximately one-third of 18p, and with the recently developed centromere-specific multi-color fluorescence in situ hybridization (cenM-FISH) technique, it was shown that the SMC was a derivative chromosome 4. The SMC was not specifically stained by arm-specific probes for chromosome 4; thus, it has been described as der(4)(:p11 --> q11:). Microsatellite analysis resulted in a partial maternal uniparental isodisomy (UPD) for chromosome 4p15-16 and a maternal origin for two chromosomes 21. Until now only two similar cases have been described in the literature, but without clarifying the origin of the SMC and without looking for an additional UPD. This is the only reported case of a UPD 4p in a liveborn child.
authors.affiliation: Institute of Human Genetics and Anthropology, Jena, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Starke
authors.forename: Beate
authors.initials: B
authors.lastname: Mitulla
authors.forename: Angela
authors.initials: A
authors.lastname: Nietzel
authors.forename: Anita
authors.initials: A
authors.lastname: Heller
authors.forename: Volkmar
authors.initials: V
authors.lastname: Beensen
authors.forename: Gisela
authors.initials: G
authors.lastname: Grosswendt
authors.forename: Uwe
authors.initials: U
authors.lastname: Claussen
authors.forename: Ferdinand
authors.initials: F
authors.lastname: von Eggeling
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr
mesh_terms: D002869:Chromosome Aberrations; D002871:Chromosome Banding; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D004314:Down Syndrome / Q000235:genetics / Q000473:pathology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007621:Karyotyping; D008297:Male; D014314:Trisomy; D024182:Uniparental Disomy