title: Phenotypic spectrum of 20 novel patients with molecularly defined supernumerary marker chromosomes 15 and a review of the literature.
abstract: Supernumerary marker chromosomes (SMC) originating from chromosome 15 are the most common SMCs. They encompass clinically irrelevant SMC(15)s containing only heterochromatin and 15p material, and clinically relevant SMC(15)s that consist of both eu- and heterochromatic 15q material. On the basis of size, the clinically relevant SMC(15)s can be subdivided into type A, "large" asymmetric and type B, "small" symmetric SMC(15)s. Type B SMC(15)s contain the triplicated 15pter to BP3 (located at 26.5 Mb) region, while type A SMC(15)s consist of 15pter --> BP4(28.5 Mb)::BP5(30.5 Mb) --> 15pter. In this study, the clinical and molecular features of 18 patients with A and B SMC(15)s and two patients with a partial trisomy 15q were reviewed. Questionnaires (including Child Behavior Check Lists) were used to assess behavior and developmental features in more detail. The marker size and parental origin were determined by multiplex ligation-dependent probe amplification (MLPA). Based on the MLPA results, the majority of patients (14/18) had type A SMC(15)s. The phenotype observed did not show significant differences between types A and B SMC(15)s. A high prevalence of autistic-like behavior, attention problems, aggressive behavior, anxiety, and sleeping problems was reported. Motor and speech development varied extensively among the patients. An association was found between positive seizure history and degree of intellectual disability.
authors.affiliation: Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. t.kleefstra@antrg.umcn.nl
authors.forename: Tjitske
authors.initials: T
authors.lastname: Kleefstra
authors.forename: Nicole
authors.initials: N
authors.lastname: de Leeuw
authors.forename: Roy
authors.initials: R
authors.lastname: Wolf
authors.forename: Willy M
authors.initials: WM
authors.lastname: Nillesen
authors.forename: Gaby
authors.initials: G
authors.lastname: Schobers
authors.forename: Hanneke
authors.initials: H
authors.lastname: Mieloo
authors.forename: Marjolein
authors.initials: M
authors.lastname: Willemsen
authors.forename: Concetta Simona
authors.initials: CS
authors.lastname: Perrotta
authors.forename: Pino J
authors.initials: PJ
authors.lastname: Poddighe
authors.forename: Ilse
authors.initials: I
authors.lastname: Feenstra
authors.forename: Jos
authors.initials: J
authors.lastname: Draaisma
authors.forename: Conny M A
authors.initials: CM
authors.lastname: van Ravenswaaij-Arts
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D001523:Mental Disorders / Q000235:genetics*; D010641:Phenotype; D012640:Seizures / Q000235:genetics; D011795:Surveys and Questionnaires
chemical_list: D005819:Genetic Markers