title: A de novo 1.1-1.6 Mb subtelomeric deletion of chromosome 20q13.33 in a patient with learning difficulties but without obvious dysmorphic features.
abstract: We report on a de novo submicroscopic deletion of 20q13.33 identified by subtelomeric fluorescence in situ hybridization (FISH) in a 4-year-old girl with learning difficulties, hyperlaxity and strabismus, but without obvious dysmorphic features. Further investigations by array-based comparative genomic hybridization (array-CGH) and FISH analysis allowed us to delineate the smallest reported subterminal deletion of chromosome 20q, spanning a 1.1-1.6 Mb with a breakpoint localized between BAC RP5-887L7 and RP11-261N11. The genes CHRNA4 and KCNQ2 implicated in autosomal dominant epilepsy are included in the deletion interval. Subterminal 20q deletions as found in the present patient have, to our knowledge, only been reported in three patients. We review the clinical and behavioral phenotype of such "pure" subterminal 20q deletions.
authors.affiliation: Service of Medical Genetics, Department of Gynecology and Obstetrics, Geneva University Hospitals, Geneva, Switzerland. frederique.bena@hcuge.ch
authors.forename: Frédérique
authors.initials: F
authors.lastname: Béna
authors.forename: Armand
authors.initials: A
authors.lastname: Bottani
authors.forename: Fabienne
authors.initials: F
authors.lastname: Marcelli
authors.forename: Loredana D'Amato
authors.initials: LD
authors.lastname: Sizonenko
authors.forename: Bernard
authors.initials: B
authors.lastname: Conrad
authors.forename: Sophie
authors.initials: S
authors.lastname: Dahoun
mesh_terms: D002675:Child, Preschool; D002872:Chromosome Deletion; D002890:Chromosomes, Human, Pair 20; D005145:Face / Q000002:abnormalities; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007859:Learning Disabilities / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D013285:Strabismus / Q000175:diagnosis; D016615:Telomere / Q000235:genetics*