title: Distal 22q11.2 microduplication combined with typical 22q11.2 proximal deletion: a case report.
abstract: The 22q11 chromosomal region contains low copy repeats (LCRs) sequences that mediate non-allelic homologous recombination, which predisposes to copy number variations (CNVs) at this locus. Hemizygous deletions of the proximal 22q11.2 region result in the 22q11.2 deletion syndrome (22q11.2 DS). In addition, 22q11.2 duplications involving the distal LCR22s have been reported. This article describes a patient presenting a 2.5-Mb de novo deletion at proximal 22q11.21 region (between LCRs A-D), combined with a 1.3-Mb maternally inherited duplication at distal 22q11.23 region (between LCRs F-H). The presence of concomitant chromosomal imbalances found in this patient has not been reported previously. Clinical and molecular data were compared with literature, in order to contribute to genotype-phenotype correlation. These findings exemplify the complexity and genetic heterogeneity observed in 22q11.2 deletion syndrome and highlights the difficulty to make genetic counseling and predict phenotypic consequences in these situations.
authors.affiliation: Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas (UNICAMP), Sao Paulo, Brazil.
authors.forename: Miriam Coelho
authors.initials: MC
authors.lastname: Molck
authors.forename: Társis Paiva
authors.initials: TP
authors.lastname: Vieira
authors.forename: Milena
authors.initials: M
authors.lastname: Simioni
authors.forename: Ilária Cristina
authors.initials: IC
authors.lastname: Sgardioli
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: dos Santos
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Xavier
authors.forename: Vera Lúcia
authors.initials: VL
authors.lastname: Gil-da-Silva-Lopes
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D000328:Adult; D002648:Child; D058674:Chromosome Duplication / Q000235:genetics*; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D004062:DiGeorge Syndrome / Q000150:complications* / Q000235:genetics*; D019066:Facies; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D008297:Male
keywords: 22q11.2 deletion; 22q11.2 distal duplication; copy number variations; genotype-phenotype correlation