title: Clinical and molecular characterization of the 20q11.2 microdeletion syndrome: six new patients.
abstract: Interstitial microdeletions of 20q chromosome are rare, only 17 patients have been reported in the literature to date. Among them, only six carried a proximal 20q11.21-q11.23 deletion, with a size ranging from 2.6 to 6.8 Mb. The existence of a 20q11.2 microdeletion syndrome has been proposed, based on five previously reported cases that displayed anomalies of the extremities, intellectual disability, feeding difficulties, craniofacial dysmorphism and variable malformations. To further characterize this syndrome, we report on six new patients with 20q11.2 microdeletions diagnosed by whole-genome array-based comparative genomic hybridization. These patient reports more precisely refined the phenotype and narrowed the minimal critical region involved in this syndrome. Careful clinical assessment confirms the distinctive clinical phenotype. The craniofacial dysmorphism consists of high forehead, frontal bossing, enophthalmos, and midface hypoplasia. We have identified a 1.62 megabase minimal critical region involved in this syndrome encompassing three genes—GDF5, EPB41L1, andSAMHD1—which are strong candidates for different aspects of the phenotype. These results support that 20q11.2 microdeletion syndrome is a new contiguous gene deletion syndrome with a recognizable phenotype.
authors.affiliation: Unité de Génétique Médicale et Oncogénétique, Centre Hospitalier Universitaire Amiens Picardie, Amiens, France; Laboratoire de Cytogénétique et Biologie de la Reproduction, Centre Hospitalier Universitaire Amiens Picardie, Amiens, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Jedraszak
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Demeer
authors.forename: Michèle
authors.initials: M
authors.lastname: Mathieu-Dramard
authors.forename: Joris
authors.initials: J
authors.lastname: Andrieux
authors.forename: Aline
authors.initials: A
authors.lastname: Receveur
authors.forename: Astrid
authors.initials: A
authors.lastname: Weber
authors.forename: Una
authors.initials: U
authors.lastname: Maye
authors.forename: Nicola
authors.initials: N
authors.lastname: Foulds
authors.forename: I K
authors.initials: IK
authors.lastname: Temple
authors.forename: John
authors.initials: J
authors.lastname: Crolla
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Alex-Cordier
authors.forename: Damien
authors.initials: D
authors.lastname: Sanlaville
authors.forename: Lisa
authors.initials: L
authors.lastname: Ewans
authors.forename: Meredith
authors.initials: M
authors.lastname: Wilson
authors.forename: Ruth
authors.initials: R
authors.lastname: Armstrong
authors.forename: Amanda
authors.initials: A
authors.lastname: Clarkson
authors.forename: Henri
authors.initials: H
authors.lastname: Copin
authors.forename: Gilles
authors.initials: G
authors.lastname: Morin
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis* / Q000235:genetics*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D056905:Chromosome Breakpoints; D002872:Chromosome Deletion; D002890:Chromosomes, Human, Pair 20; D055028:Comparative Genomic Hybridization; D019066:Facies; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D010641:Phenotype; D013577:Syndrome; D055815:Young Adult
keywords: 20q11.2 deletion syndrome; 20q11.21q11.23 deletion; Anomalies of feet; Anomalies of hands; Contiguous gene deletion syndrome; EPB41L1; Facial dysmorphisms; GDF5; SAMHD1