Cerebral palsy (CP), a neurodevelopmental disorder characterized by irreversible, nonprogressive central motor dysfunction, is commonly associated with prematurity or perinatal brain injury. However, accumulating evidence suggests deleterious genomic variants may contribute to CP in addition to environmental insults. To identify genes contributing to risk for CP, we performed whole-exome sequencing on 250 parent-offspring CP trios. We identified a significant contribution of damaging de novo mutations (DNMs), especially in genes that are intolerant to loss of function mutations. Eight genes had multiple, independently-arising damaging DNMs, including two novel CP-associated genes, FBXO31 and RHOB, and four genes previously implicated in cerebral palsy phenotypes, TUBA1A, CTNNB1, SPAST, and ATL1. Functional experiments, including molecular and biochemical assays and patient fibroblast studies indicate that the recurrent RHOB mutation identified in patients enhances Rho effector binding in the active state and that the FBXO31 mutation leads to elevated levels of cyclin D. Analysis of candidate CP risk genes highlighted genetic overlap with hereditary spastic paraplegia as well as intellectual disability, autism, and epilepsy, converging with epidemiologic findings. Computational network analysis of risk genes identified significant enrichment of Rho GTPase, extracellular matrix, focal adhesions, cytoskeleton, and cell projection pathways. CP risk genes in Rho GTPase, cytoskeleton and cell projection pathways were found to play an important role in neuromotor development via a Drosophila reverse genetics screen. Based on enrichment analysis, we estimate that an excess of damaging de novo and inherited recessive variants collectively account for ~14% of the cases in our cohort, whereas perinatal asphyxia is currently estimated to occur in 8-10% of CP cases. Together, these findings provide evidence for the role of genetically-mediated dysregulation of early brain connectivity in CP.

Glutamatergic neurotransmission governs excitatory signaling in the mammalian brain, and abnormalities of glutamate signaling have been shown to contribute to both epilepsy and hyperkinetic movement disorders. The etiology of many severe childhood movement disorders and epilepsies remains uncharacterized. We describe a neurological disorder with epilepsy and prominent choreoathetosis caused by biallelic pathogenic variants in FRRS1L, which encodes an AMPA receptor outer-core protein. Loss of FRRS1L function attenuates AMPA-mediated currents, implicating chronic abnormalities of glutamatergic neurotransmission in this monogenic neurological disease of childhood.

The vacuolar H ؉ -ATPase (V-ATPase) along with ion channels and transporters maintains vacuolar pH. V-ATPase ATP hydrolysis is coupled with proton transport and establishes an electrochemical gradient between the cytosol and vacuolar lumen for coupled transport of metabolites. Btn1p, the yeast homolog to human CLN3 that is defective in Batten disease, localizes to the vacuole. We previously reported that Btn1p is required for vacuolar pH maintenance and ATP-dependent vacuolar arginine transport. We report that extracellular pH alters both V-ATPase activity and proton transport into the vacuole of wild-type Saccharomyces cerevisiae. V-ATPase activity is modulated through the assembly and disassembly of the V 0 and V 1 V-ATPase subunits located in the vacuolar membrane and on the cytosolic side of the vacuolar membrane, respectively. V-ATPase assembly is increased in yeast cells grown in high extracellular pH. In addition, at elevated extracellular pH, S. cerevisiae lacking BTN1 (btn1-⌬), have decreased V-ATPase activity while proton transport into the vacuole remains similar to that for wild type. Thus, coupling of V-ATPase activity and proton transport in btn1-⌬ is altered. We show that down-regulation of V-ATPase activity compensates the vacuolar pH imbalance for btn1-⌬ at early growth phases. We therefore propose that Btn1p is required for tight regulation of vacuolar pH to maintain the vacuolar luminal content and optimal activity of this organelle and that disruption in Btn1p function leads to a modulation of V-ATPase activity to maintain cellular pH homeostasis and vacuolar luminal content.The neuronal ceroid-lipofuscinoses (NCLs) 2 are the most common group of progressive neurodegenerative diseases in children, with an incidence as high as 1 in 12,500 live births (1, 2). The NCL disorders are inherited in an autosomal recessive manner, with mutations in seven distinct genes resulting in pathologically similar disease with a different age of onset (3, 4). The NCLs are characterized by the accumulation of autofluorescent hydrophobic material in the lysosomes of neurons, and to lesser extent, other cell types (5, 6); however, the molecular basis behind this storage and the disease remains unknown. The juvenile form of NCL results from mutations in the CLN3 gene, which codes for a lysosomal transmembrane protein (7-9).We have previously reported that the Saccharomyces cerevisiae BTN1 gene product has high sequence similarity with the human CLN3 gene product. BTN1 encodes a non-essential protein that is 39% identical and 59% similar to human CLN3 (10). Studies have revealed that Btn1p is located in the vacuolar membrane (11, 12) and, although the primary function of this protein remains unclear, it has been implicated in several cellular pathways. Lack of BTN1 resulted in resistance to D-(Ϫ)-threo-2-amino-1-[p-nitrophenyl]-1,3-propanediol (ANP), and this phenotype is complemented by expression of human Cln3p, indicating that yeast Btn1p and human Cln3p likely have a conserved function (13). Resistance of btn1-⌬...