title: A 2.3 Mb duplication of chromosome 8q24.3 associated with severe mental retardation and epilepsy detected by standard karyotype.
abstract: Chromosome duplications are found in about 2% of subjects with a typical chromosomal phenotype but their frequency is likely to be higher, as suggested by the first array-CGH data. According to the orientation of the duplicated segment, duplications may be in tandem or inverted. The latter are usually associated with a distal deletion. We studied a de novo 2.3 Mb inverted duplication of 8q24.3 without apparently associated deletion in a subject with profound psychomotor retardation, idiopathic epilepsy and growth delay. In spite of its small size, the presence of the rearrangement was suspected on standard karyotypes (approximately 400 bands) and later confirmed by Fluorescent in situ hybridization (FISH) analysis. We hypothesize that the GRINA gene, a glutamate binding subunit of NMDA receptor ion channel lying within the duplicated segment, may be responsible for the epilepsy. This paper confirms that small subtelomeric de novo duplications may be responsible for mental retardation, facial dysmorphisms and/or congenital malformations, although their presence may be overlooked by FISH analysis.
authors.affiliation: IRCCS Eugenio Medea, Bosisio Parini, Italy. bonaglia@bp.lnf.it
authors.forename: Maria Clara
authors.initials: MC
authors.lastname: Bonaglia
authors.forename: Roberto
authors.initials: R
authors.lastname: Giorda
authors.forename: Romano
authors.initials: R
authors.lastname: Tenconi
authors.forename: Marco
authors.initials: M
authors.lastname: Pessina
authors.forename: Tiziano
authors.initials: T
authors.lastname: Pramparo
authors.forename: Renato
authors.initials: R
authors.lastname: Borgatti
authors.forename: Orsetta
authors.initials: O
authors.lastname: Zuffardi
mesh_terms: D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D007446:Chromosome Inversion / Q000235:genetics; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D004827:Epilepsy / Q000235:genetics*; D005260:Female; D020440:Gene Duplication; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate