title: Are 22q11.2 distal deletions associated with math difficulties?
abstract: Approximately 6% of school-aged children have math difficulties (MD). A neurogenetic etiology has been suggested due to the presence of MD in some genetic syndromes such as 22q11.2DS. However, the contribution of 22q11.2DS to the MD phenotype has not yet been investigated. This is the first population-based study measuring the frequency of 22q11.2DS among school children with MD. Children (1,564) were identified in the schools through a screening test for language and math. Of these children, 152 (82 with MD and 70 controls) were selected for intelligence, general neuropsychological, and math cognitive assessments and for 22q11.2 microdeletion screening using MLPA. One child in the MD group had a 22q11.2 deletion spanning the LCR22-4 to LCR22-5 interval. This child was an 11-year-old girl with subtle anomalies, normal intelligence, MD attributable to number sense deficit, and difficulties in social interactions. Only 19 patients have been reported with this deletion. Upon reviewing these reports, we were able to characterize a new syndrome, 22q11.2 DS (LCR22-4 to LCR22-5), characterized by prematurity; pre- and postnatal growth restriction; apparent hypotelorism, short/upslanting palpebral fissures; hypoplastic nasal alae; pointed chin and nose; posteriorly rotated ears; congenital heart defects; skeletal abnormalities; developmental delay, particularly compromising the speech; learning disability (including MD, in one child); intellectual disability; and behavioral problems. These results suggest that 22q11.2 DS (LCR22-4 to LCR22-5) may be one of the genetic causes of MD.
authors.affiliation: Pós-Graduação em Genética, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; Departamento de Biologia Geral, Instituto de Ciências Biológias, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Maria Raquel Santos
authors.initials: MR
authors.lastname: Carvalho
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Vianna
authors.forename: Lívia de Fátima Silva
authors.initials: Lde F
authors.lastname: Oliveira
authors.forename: Annelise Julio
authors.initials: AJ
authors.lastname: Costa
authors.forename: Pedro
authors.initials: P
authors.lastname: Pinheiro-Chagas
authors.forename: Rosane
authors.initials: R
authors.lastname: Sturzenecker
authors.forename: Paulo Ricardo Gazzola
authors.initials: PR
authors.lastname: Zen
authors.forename: Rafael Fabiano Machado
authors.initials: RF
authors.lastname: Rosa
authors.forename: Marcos José Burle
authors.initials: MJ
authors.lastname: de Aguiar
authors.forename: Vitor Geraldi
authors.initials: VG
authors.lastname: Haase
mesh_terms: D002648:Child; D004062:DiGeorge Syndrome / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007859:Learning Disabilities / Q000235:genetics*; D008297:Male; D008433:Mathematics
keywords: 22q11.2 DS (LCR22-4 to LCR22-5); chromosome 22q11.2 deletion syndrome; developmental dyscalculia; distal; learning disability; math difficulties