title: Unbalanced translocation 9;16 in two children with dysmorphic features, and severe developmental delay: Evidence of cross-over within derivative chromosome 9 in patient #1.
abstract: We describe 2 children with dysmorphic features, and severe developmental delay presenting with overlapping unbalanced translocations of 9q34.3 and 16p13. Patient #1: A 4 year old African-American female with normal karyotype with a pericentric inversion on one chromosome 9 known to be a benign variant. Low resolution array CGH revealed a single BAC clone loss at 9q34.3 and a single BAC clone gain at 16p13.3, confirmed by FISH. Whole genome SNP array analysis refined these findings, identifying a terminal 1.28 Mb deletion (138,879,862-140,164,310) of 9q34.3 and a terminal 1.62 Mb duplication (45,320-1,621,753) of 16p13.3. Sub-telomeric FISH showed an unbalanced cryptic translocation involving the inverted chromosome 9 and chromosome 16. FISH of the father showed a balanced t(9;16)(q34.3;p13.3) involving the non-inverted chromosome 9, and a pericentric inversion on the normal 9 homologous chromosome. The presence of two rearrangements on chromosome 9, both an unbalanced translocation and a pericentric inversion, indicates recombination between the inverted and derivative 9 homologues from her father. Patient #2: A 1 year old Iraqi-Moroccan female with normal karyotype. Array-CGH identified a 0.56 Mb deletion of 9q34.3 (139,586,637-140,147,760) and an 11.31 Mb duplication of 16p13.3p13.13 (31,010-11,313,519). Maternal FISH showed a balanced t(9;16)(q34.3;p13.13). Both patients present with similar clinical phenotype.
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, USA.
authors.forename: Regina M
authors.initials: RM
authors.lastname: Zambrano
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wohler
authors.forename: Göran
authors.initials: G
authors.lastname: Annerén
authors.forename: Ann-Charlotte
authors.initials: AC
authors.lastname: Thuresson
authors.forename: Garry R
authors.initials: GR
authors.lastname: Cutting
authors.forename: Denise A
authors.initials: DA
authors.lastname: Batista
mesh_terms: D002675:Child, Preschool; D007446:Chromosome Inversion; D002885:Chromosomes, Human, Pair 16; D002899:Chromosomes, Human, Pair 9; D002658:Developmental Disabilities / Q000235:genetics*; D005220:Fathers; D005260:Female; D006801:Humans; D007223:Infant; D014178:Translocation, Genetic