De novo unbalanced translocation 2;4 characterized by metaphase CGH and array CGH in a child with mental retardation and dysmorphic features.

It is known from postnatal diagnosis that imbalances of the subtelomeric regions contribute significantly to idiopathic mental retardation. We report a case of a 4-year-old child with growth retardation, minor physical abnormalities, hypotonia and developmental delay associated with a derivative chromosome 4. Molecular cytogenetic investigations were performed to characterize the chromosomal rearrangement. Multi fluorescence in situ hybridization revealed the presence of chromosome 2 material on the derivative chromosome 4. Metaphase comparative genomic hybridization detected a terminal 4q34 deletion. Array CGH analysis could precise breakpoints with duplication 2q36 → qter. The clinical phenotype was similar to those described in cases with a trisomy 2qter. This study emphasizes the value of array CGH to detect or characterize chromosome rearrangements in mentally retarded patients. Unlike metaphase CGH, the high resolution of array CGH in subtelomeric regions allows an accurate description of chromosomal aberrations.

Debost-Legrand A ，Capri Y ，Gouas L ，Pebrel-Richard C ，Veronese L ，Tchirkov A ，Haoud K ，Boespflug-Tanguy O ，Goumy C ，Vago P ... -  《-》

Subtelomeric chromosomal rearrangements detected in patients with idiopathic mental retardation and dysmorphic features.

Caliskan MO ，Karauzum SB ，Mihci E ，Tacoy S ，Luleci G ... -  《genetic counseling》

Characterization of a de novo complex chromosome rearrangement (CCR) involving chromosomes 2 and 12, associated with mental retardation and impaired speech development.

We report on a currently six-year-old patient with a de novo complex chromosome rearrangement (CCR) involving chromosomes 2 and 12. A translocation 2;12 that appeared to be reciprocal after standard banding turned out to be a complex event with seven breaks after molecular cytogenetic analyses. Array CGH analysis showed no imbalances at the breakpoints but revealed an additional microdeletion of about 80 kb on chromosome 11. The same deletion was also present in the phenotypically normal father. The patient showed relatively mild mental retardation, defined mainly as impaired speech development (orofacial dyspraxia) and psychomotor retardation. In addition, mild dysmorphic facial features like hypertelorism, a prominent philtrum and down-turned corners of the mouth were observed. We narrowed down all breakpoint regions to about 100 kb, using a panel of mapped bacterial artificial chromosome (BAC) clones for fluorescence in situ hybridization (FISH). BACs spanning or flanking all seven breakpoints were identified and no chromosomal imbalances were found consistent with the array CGH results. Our investigations resulted in the following karyotype: 46,XY,t(2;12)(2pter-->2p25.3::2p23.3-->2p25.2::2p23.3-->2p14::2q14.3-->2p14::2q14.3-->2q14.3::12q 12-->12qter;12pter-->12q12::2p25.3-->2p25.2::2q14.3-->2qter).

Schwarzbraun T ，Ullmann R ，Schubert M ，Ledinegg M ，Ofner L ，Windpassinger C ，Wagner K ，Kroisel PM ，Petek E ... -  《-》

Cytogenetic, FISH and array-CGH characterization of a complex chromosomal rearrangement carried by a mentally and language impaired patient.

Ballarati L ，Recalcati MP ，Bedeschi MF ，Lalatta F ，Valtorta C ，Bellini M ，Finelli P ，Larizza L ，Giardino D ... -  《-》

Detection of chromosomal imbalances in children with idiopathic mental retardation by array based comparative genomic hybridisation (array-CGH).

Schoumans J ，Ruivenkamp C ，Holmberg E ，Kyllerman M ，Anderlid BM ，Nordenskjöld M ... -  《-》