Dendritic spine pathology in autism： lessons learned from mouse models

Autism spectrum disorders （ASD） are a group of neurodevelopmental disorders that affect up to 1.5% of population in the world. Recent large scale genomic studies show that genetic causes of ASD are very heterogeneous. Gene ontology, pathway analysis and animal model studies have revealed several potential converging mechanisms including postsynaptic dysfunction of excitatory synapses. In this review, we focus on the structural and functional specializations of dendritic spines, and describe their defects in ASD. We use Fragile X syndrome, Rett syndrome and Phe- lan-McDermid syndrome, three of the most studied neurodevelopmental disorders with autism features, as examples to demonstrate the significant contribution made by mouse models towards the understanding of monogenic ASD. We envision that the development and application of new technologies to study the function ofdendritic spines in valid animal models wi l l eventually lead to innovative treatments for ASD.

Mutation inε-Sarcoglycan Induces a Myoclonus-Dystonia Syndrome-Like Movement Disorder in Mice

Myoclonus dystonia syndrome(MDS)is an inherited movement disorder,and most MDS-related mutations have so far been found in theε-sarcoglycan(SGCE)coding gene.By generating SGCE-knockout(KO)and human 237 C>T mutation knock-in(KI)mice,we showed here that both KO and KI mice exerted typical movement defects similar to those of MDS patients.SGCE promoted filopodia development in vitro and inhibited excitatory synapse formation both in vivo and in vitro.Loss of function of SGCE leading to excessive excitatory synapses that may ultimately contribute to MDS pathology.Indeed,using a zebrafish MDS model,we found that among 1700 screened chemical compounds,Vigabatrin was the most potent in readily reversing MDS symptoms of mouse disease models.Our study strengthens the notion that mutations of SGCE lead to MDS and most likely,SGCE functions to brake synaptogenesis in the CNS.