Copy number variants and infantile spasms: evidence for abnormalities in ventral forebrain development and pathways of synaptic function

• Published in: European journal of human genetics : EJHG Vol. 19; no. 12; pp. 1238 - 1245
• Main Authors: Paciorkowski, Alex R, Thio, Liu Lin, Rosenfeld, Jill A, Gajecka, Marzena, Gurnett, Christina A, Kulkarni, Shashikant, Chung, Wendy K, Marsh, Eric D, Gentile, Mattia, Reggin, James D, Wheless, James W, Balasubramanian, Sandhya, Kumar, Ravinesh, Christian, Susan L, Marini, Carla, Guerrini, Renzo, Maltsev, Natalia, Shaffer, Lisa G, Dobyns, William B
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2011; Nature Publishing Group
• Subjects: 631/114; 631/208/2489/1381; 631/208/457/649; 631/378/1689/178; Autism; Bioinformatics; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Brain research; Child clinical studies; Chromosome Aberrations; Chromosomes; Classical genetics, quantitative genetics, hybrids; Clonal deletion; Computational Biology; Copy number; Cytogenetics; Developmental disorders; Encephalopathy; Epilepsy; Forebrain; Fundamental and applied biological sciences. Psychology; Gene Dosage; Gene Expression; Gene Regulatory Networks; General aspects. Genetic counseling; Genes; Genetic diversity; Genetic Loci; Genetics; Genetics of eukaryotes. Biological and molecular evolution; Genotype & phenotype; Human; Human Genetics; Humans; Hypotheses; Infant; Infant, Newborn; Infantile autism; Infants; Medical genetics; Medical sciences; Molecular and cellular biology; Neurology; Pathogenesis; Pediatrics; Phenotypes; Postsynaptic density; Prosencephalon - abnormalities; Prosencephalon - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Seizures; Spasms, Infantile - genetics; Synaptic Transmission - genetics; Synaptogenesis; γ-Aminobutyric acid; United States > US; Italy; copy number variation; deletion 1p36 syndrome; infantile spasms; autism; bioinformatics; Chromosomal aberration; Human; Genetic mapping; Nervous system diseases; Copy number; Variations; Developmental disorder; Variant; Autism; Deletion; Development; Spasm; Genetics; Neurological disorder; Child
• ISSN: 1018-4813; 1476-5438; 1476-5438
• DOI: 10.1038/ejhg.2011.121

Infantile spasms (ISS) are an epilepsy disorder frequently associated with severe developmental outcome and have diverse genetic etiologies. We ascertained 11 subjects with ISS and novel copy number variants (CNVs) and combined these with a new cohort with deletion 1p36 and ISS, and additional published patients with ISS and other chromosomal abnormalities. Using bioinformatics tools, we analyzed the gene content of these CNVs for enrichment in pathways of pathogenesis. Several important findings emerged. First, the gene content was enriched for the gene regulatory network involved in ventral forebrain development. Second, genes in pathways of synaptic function were overrepresented, significantly those involved in synaptic vesicle transport. Evidence also suggested roles for GABAergic synapses and the postsynaptic density. Third, we confirm the association of ISS with duplication of 14q12 and maternally inherited duplication of 15q11q13, and report the association with duplication of 21q21. We also present a patient with ISS and deletion 7q11.3 not involving MAGI2. Finally, we provide evidence that ISS in deletion 1p36 may be associated with deletion of KLHL17 and expand the epilepsy phenotype in that syndrome to include early infantile epileptic encephalopathy. Several of the identified pathways share functional links, and abnormalities of forebrain synaptic growth and function may form a common biologic mechanism underlying both ISS and autism. This study demonstrates a novel approach to the study of gene content in subjects with ISS and copy number variation, and contributes further evidence to support specific pathways of pathogenesis.