Mutations in BCKD-kinase lead to a potentially treatable form of autism with epilepsy
ABSTRACT: 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:Autism spectrum disorders (ASD) are a group of genetic disorders often overlapping with other neurological conditions. We previously described abnormalities in the branched chain amino acid (BCAA) catabolic pathway as a cause of ASD. Here we show that the solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter localized at the blood brain barrier (BBB), has an essential role in maintaining normal levels of brain BCAAs. In mice, deletion of Slc7a5 from the endothelial cells of the BBB leads to decreased levels of brain BCAAs, abnormal mRNA translation and severe neurological abnormalities. Furthermore, we identified several patients with autistic traits and motor delay carrying deleterious homozygous mutations in the SLC7A5 gene. Finally, we demonstrate that BCAA intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice. Our data elucidate a neurological syndrome defined by SLC7A5 mutations and support an essential role for the BCAA in human brain function. Overall design: RNA-sequencing of cerebellum from 3 wildtype mice and 3 Slc7a5 KO mice
Project description:Phosphatase and tensin homolog (PTEN) is a tumour suppressor gene associated with inherited tumour susceptibility conditions, macrocephaly, autism, ataxia, tremor and epilepsy. Functional implications of this protein have been investigated in Parkinson’s and Alzheimer’s diseases. We describe the first patient presented with multifocal demyelinating motor neuropathy in association with a de novo PTEN mutation. The pathogenicity of the mutation was supported by altered expression of several proteins involved in tumorigenesis and fibroblasts showed a reversible defect in catalytic activity of PTEN against the secondary substrate, phosphatidylinositol 3,4,-trisphosphate, suggesting a novel and potentially treatable mechanism for multi-focal demyelinating motor neuropathy.
Project description:Diamond-Blackfan anemia (DBA) is a congenital disorder that results predominantly from mutations in various ribosomal protein genes. In order to determine how these mutations affect the translation of specific mRNAs, we performed microarray analysis of polysomal transcripts isolated from lymphoblast cells derived from DBA patients carrying different haploinsufficient mutations in either RPS19 or RPL11. One of the few overlapping transcripts that we found significantly decreased on the polysomes codes for branched-chain aminotransferase-1 (BCAT-1). We go on to determine that translation of BCAT-1 is especially impaired in cells carrying mutations in the small ribosomal protein genes, and provide evidence that this effect is due to its unusually long 5’UTR. The BCAT-1 enzyme is critical for synthesis of the branched-chain amino acids, including leucine. It is known that DBA patients respond well to orally administered leucine, and large-scale clinical trials as such are currently underway. Our results suggest that the haploinsufficient loss of ribosomal protein genes results in a decrease of BCAT-1 translation and provide an explanation for why leucine administration is beneficial for DBA patients. In this expression study duplicate mRNA samples were generated from polysomes isolated from celllines with mutations in RPS19 or RPL11 or normal controls. In each group 3 cellines were tested. Duplicate samples were analyzed in dyeswap. As common reference the commercial universal human reference RNA (Stratagene) was used.
Project description:Arc is an activity regulated neuronal protein yet little is known about its protein interactions, assembly into multiprotein complexes, role in human disease and cognition. We applied an integrated proteomic and genetic strategy using targeted tagging of a Tandem Affinity Purification (TAP) tag and Venus fluorescent protein into the endogenous Arc gene in mice, biochemical and proteomic characterization of native complexes in wild type and knockout mice, and human genetic analyses of disease and intelligence. TAP tagging enabled efficient purification of complexes and identification of many novel Arcinteracting proteins, of which PSD95 was the most abundant. PSD95 was essential for Arc assembly into 1.5 MDa complexes and activity-dependent recruitment to excitatory synapses. Integrating human genetic data with proteomic data showed postsynaptic Arc- PSD95 complexes are enriched in schizophrenia, intellectual disability, autism and epilepsy mutations and normal variants in intelligence. Arc-PSD95 postsynaptic complexes are a molecular substrate for the convergence of normal and pathological genetic variants impacting on human cognitive function.
Project description:Kdm5c is an X-linked histone demethylase that acts as a transcriptional repressor via histone H3 lysine 4 (H3K4) – specific demethylation. In humans, KDM5C mutations cause intellectual disability and other neuropsychiatric comorbidities such as epilepsy, autism-like behavior, and aggression. To assess the role of Kdm5c in brain development and behavior, we generated mutant mice deficient for this enzyme and found cognitive deficits and other behavioral phenotypes (e.g. elevated aggression, reduced social interaction, low anxiety) in these mice. We then performed RNA-seq analysis of whole brain RNAs to determine the mis-regulated genes as listed in this dataset. Overall design: Genome-wide gene expression was determined in the brain between 3 adult male Kdm5c deficient and 3 wild type littermate mice.
Project description:Here we use 454 sequencing to determine the number and location of mutations in IgM plasma cells. Overall design: Heavy chain sequences from NP-specific plasma cells were analyzed for mutation.
Project description:gene expression profiles of lymphoblastoid cells from individuals with autism and full mutation of FMR1 Experiment Overall Design: Cy5; each individual with autism and FMR1FM Experiment Overall Design: Cy3; pool of 14 unrelated individuals.
Project description:gene expression profiles of lymphoblastoid cells from individuals with autism and full mutation of FMR1 Keywords: autism with FMR1-FM Overall design: Cy5; each individual with autism and FMR1FM Cy3; pool of 14 unrelated individuals.
Project description:RBFOX3 mutations are linked to epilepsy and cognitive impairments, but the underlying pathophysiology of these disorders is poorly understood. Here we report replication of human symptoms in a mouse model with disrupted Rbfox3. Rbfox3 knockout mice displayed increased seizure susceptibility and decreased anxiety-related behaviors. Focusing on hippocampal phenotypes, we found Rbfox3 knockout mice showed increased expression of plasticity genes Egr4 and Arc, and the synaptic transmission and plasticity were defective in the mutant perforant pathway. The mutant dentate granules cells exhibited an increased frequency, but normal amplitude, of excitatory synaptic events, and this change was associated with an increase in the neurotransmitter release probability and dendritic spine density. Together, our results demonstrate anatomical and functional abnormality in Rbfox3 knockout mice, and may provide mechanistic insights for RBFOX3-related human brain disorders. Two samples (one is from wild-type and the other is from Rbfox3 homozygous knockout mice)