Project description:Epilepsy is a heterogenous group of disorders defined by recurrent seizure activity due to abnormal synchronized activity of neurons. A growing number of epilepsy cases are believed to be caused by genetic factors and copy number variants (CNV) contribute to up to 5% of epilepsy cases. However, CNVs in epilepsy are usually large deletions or duplications involving multiple neurodevelopmental genes. Here we identify focal amplifications of regulatory regions of receptor tyrosine kinase genes as a genetic abnormality in epileptogenic brains. Whole genome DNA methylation profiling identified three main clusters of which one showed strong association with receptor tyrosine kinase genes. By copy number analysis, we identified focal copy number gains involving EGFR and PDGFRA in brain tissue of patients who underwent seizure focus resection for treatment-resistant epilepsy. The dysplastic neurons showed marked overexpression of pEGFR and pPDGFRA, while glial and endothelial cells were negative. Sequencing and DNA methylation analysis revealed that enhancer regions of EGFR and PDGFRA gene promoter were amplified, while coding regions did not show copy number abnormalities or somatic mutations. Our results identify somatic focal copy number gains of noncoding regulatory regions in the brain as a previously unrecognized genetic driver in epilepsy. Somatic copy number aberrations of regulatory regions represent a mechanism of abnormal activation of receptor tyrosine kinase genes in epilepsy. Upregulated receptor tyrosine kinases provide a potential avenue for therapy in seizure disorders.
Project description:Autism is present in 1% of the population, yet treatments are extremely limited. We identified homozygous inactivating mutations in the BCKDK gene in families presenting with autism and epilepsy. The encoded branched chain ketoacid dehydrogenase kinase protein is responsible for phosphorylation-mediated inactivation of the E1-alpha subunit of branched chain ketoacid dehydrogenase, itself mutated in Maple Syrup Urine Disease (MSUD). Patients with homozygous BCKDK mutations display reductions in BCKDK mRNA and protein, E1-alpha phosphorylation and serum branched chain amino acids (BCAAs). Bckdk knockout mice show abnormal brain amino acids profiles and neurobehavioral defects, which are largely corrected by dietary BCAA supplementation. Thus autism presenting with epilepsy due to BCKDK mutations represent a new and potentially treatable disease. A 51 chip study that includes both human and mouse samples to investigate the expression changes that result in a mutation or knockout of the BCKDK gene. Starting with human fibroblasts from three affecteds and two controls, cells were converted into IPSs, then NPCs, and finally Neurons. Each of these cell types were used to view the expression changes between a cells with a BCKDK mutation versus controls. Finally, a mouse knockout was performed to verify consistency of the expression pattern differences between the BCKCK knockout and wild-type. Samples are labeled as Affected if the sample came from a patient with a BCKDK mutation and WildType otherwise. Samples were usually replicated once.
Project description:Malformations of cortical development (MCD) are neurological conditions displaying focal disruption of cortical architecture and cellular organization arising during embryogenesis, largely from somatic mosaic mutations. Identifying the genetic causes of MCD has been a challenge, as mutations remain at low allelic fraction in brain tissue resected to treat epilepsy. Here, we report genetic atlas from 283 brain resections, identifying 69 mutated genes through intensive profiling of somatic mutations, combining whole-exome and targeted-amplicon sequencing with functional validation and single-cell sequencing. Genotype-phenotype correlation analysis elucidated specific MCD gene sets associating distinct pathophysiological and clinical phenotypes. Moreover, the unique spatiotemporal expression patterns deconvolved from single-nuclear transcriptional sequences of mutated genes in control and patient brains suggest critical roles driving excitatory neurogenic pools during brain development, and in establishing neuronal excitation after birth.