title: Application of molecular and cytogenetic techniques to the detection of a de novo unbalanced t(11q;21q) in a patient previously diagnosed as having monosomy 21.
abstract: The occurrence of complete autosomal monosomy in man is extremely rare and generally considered to be incompatible with life. Since the introduction of banding techniques in human cytogenetics, several cases of presumptive monosomy for chromosome 21 have nevertheless been reported. However, it has been suggested that most, if not all, of these cases may represent unbalanced translocations or other structural aberrations resulting in only partial monosomy 21. Here we described a patient in whom full monosomy 21 was initially diagnosed by routine karyotyping. Re-examination with a combination of high resolution banding technique, chromosome painting and DNA polymorphism analysis demonstrated the presence of an unbalanced translocation between the long arms of chromosome 11 and 21, respectively. Consequently, the case was re-classified as a partial monosomy for the proximal long arm of chromosome 21.
authors.affiliation: Department of Pediatrics, Viborg Hospital, Denmark.
authors.forename: B
authors.initials: B
authors.lastname: Hertz
authors.forename: C A
authors.initials: CA
authors.lastname: Brandt
authors.forename: M B
authors.initials: MB
authors.lastname: Petersen
authors.forename: S
authors.initials: S
authors.lastname: Pedersen
authors.forename: U
authors.initials: U
authors.lastname: König
authors.forename: H
authors.initials: H
authors.lastname: Strømkjaer
authors.forename: P K
authors.initials: PK
authors.lastname: Jensen
mesh_terms: D002871:Chromosome Banding; D002880:Chromosomes, Human, Pair 11; D002891:Chromosomes, Human, Pair 21; D003951:Diagnostic Errors; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D009006:Monosomy; D011110:Polymorphism, Genetic; D013194:Staining and Labeling; D014178:Translocation, Genetic