title: Possible genes responsible for developmental delay observed in patients with rare 2q23q24 microdeletion syndrome: Literature review and description of an additional patient.
abstract: Cases of 2q23q24 microdeletion syndrome are rare. Patients with chromosomal deletions in this region often show language impairment and/or developmental delay of variable severity. Previous genotype-phenotype correlation study suggested GALNT13 and KCNJ3 as possible candidate genes for such phenotypes. We identified a new overlapping deletion in a patient with severe developmental delay. The identified deletion extended toward the distal 2q24.1 region, and more severe phenotypes in the present patient were considered to be related to the additionally deleted genes including NR4A2 and GPD2. Previously reported chromosomal translocation and the mutation identified in GPD2 suggested that this gene would be responsible for the developmental delay. Re-evaluation for the critical region for behavior abnormalities commonly observed in the patients with overlapping deletions of this region suggested that KCNJ3 rather than GALNT13 may be responsible for abnormal behaviors, although there was phenotypic variability. Combinatory deletions involving KCNJ3 and GPD2 may lead to more severe developmental delay. Further studies would be necessary to establish clearer genotype-phenotype correlation in patients with 2q23q24 microdeletion syndrome.
authors.affiliation: Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan.|Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Shimojima
authors.affiliation: Department of Medical Genetics, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Okamoto
authors.affiliation: Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan.|Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D002648:Child; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2 / Q000737:chemistry*; D055028:Comparative Genomic Hybridization; D002658:Developmental Disabilities / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels / Q000172:deficiency / Q000235:genetics*; D015870:Gene Expression; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D009154:Mutation; D017350:N-Acetylgalactosaminyltransferases / Q000172:deficiency / Q000235:genetics*; D010641:Phenotype
chemical_list: D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; C497066:KCNJ3 protein, human; D017350:N-Acetylgalactosaminyltransferases; C000589774:GALNT13 protein, human
keywords: Microarray; contiguous gene deletion syndrome; modifier; overlapping deletion