title: A familial inverted duplication 2q33-q34 identified and delineated by multiple cytogenetic techniques.
abstract: We describe a unique family with two children having a delay in psychomotor development. In both children we identified an interstitial duplication dup(2)(q34q33) using multiple, complementary molecular cytogenetic techniques. Comparative genomic hybridisation (CGH) and array-CGH were used to determine the size and the location of the duplicated region, the orientation of the duplicated region was identified with fluorescence in situ hybridisation (FISH). Both parents demonstrated a normal karyotype and normal CGH and array-CGH-profiles. However, FISH on peripheral blood cells from the mother showed the inv dup(2) in 9% of metaphases and 19% of interphase nuclei. To our knowledge this is the first report of a mosaic carrier of duplication in the long arm of chromosome 2. The finding of chromosomal mosaicism of at least 19% in the mother increases the recurrence risk. The exact characterisation of the inv dup(2) with FISH probes enabled us to offer a reliable prenatal FISH test. Comparison of the clinical features of the two children with those of previously described cases supports the hypothesis that the characteristic facial phenotype is linked to the distal part of the 2q33-q37 region. This report illustrates that in case of two sibs with an identical structural chromosomal abnormality the possibility of parental chromosomal mosaicism must be thoroughly investigated.
authors.affiliation: Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Bert H
authors.initials: BH
authors.lastname: Eussen
authors.forename: Ingrid
authors.initials: I
authors.lastname: van de Laar
authors.forename: Hannie
authors.initials: H
authors.lastname: Douben
authors.forename: Leo
authors.initials: L
authors.lastname: van Kempen
authors.forename: Ron
authors.initials: R
authors.lastname: Hochstenbach
authors.forename: Stella A
authors.initials: SA
authors.lastname: De Man
authors.forename: Diane
authors.initials: D
authors.lastname: Van Opstal
authors.forename: Annelies
authors.initials: A
authors.lastname: de Klein
authors.forename: Pino J
authors.initials: PJ
authors.lastname: Poddighe
mesh_terms: D015193:Chorionic Villi Sampling; D007446:Chromosome Inversion; D002874:Chromosome Mapping; D020223:Chromosome Painting; D002889:Chromosomes, Human, Pair 2; D020732:Cytogenetic Analysis / Q000379:methods*; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D020440:Gene Duplication; D006579:Heterozygote; D006801:Humans; D007621:Karyotyping; D009030:Mosaicism; D009693:Nucleic Acid Hybridization; D010375:Pedigree; D035781:Siblings
chemical_list: D004247:DNA