Synaptic dysfunction in human neurons with Autism associated deletions in PTCHD1-AS

The Xp22.11 locus that encompasses PTCHD1, DDX53, and the long noncoding RNA (lncRNA) PTCHD1-AS is frequently disrupted in males with autism spectrum disorder (ASD), but the functional consequences of these genetic risk factors for ASD are unknown. : iPSC-derived neurons from the ASD subjects exhibited reduced miniature excitatory post-synaptic current (mEPSC) frequency and NMDA receptor hypofunction. We found that 35 ASD-associated deletions mapping to the PTCHD1 locus disrupt exons of PTCHD1-AS. We also report a novel ASD-associated deletion of PTCHD1-AS exon 3, and we show exon 3 loss alters PTCHD1-AS splicing without affecting expression of the neighboring PTCHD1 coding gene. Finally, targeted disruption of PTCHD1-AS exon 3 recapitulated diminished mEPSC frequency, supporting a role for the lncRNA in the etiology of ASD. Our genetic findings provide strong evidence that PTCHD1-AS deletions are risk factors for ASD, and human iPSC-derived neurons implicate these deletions in the neurophysiology of excitatory synapses and in ASD-associated synaptic impairment. To evaluate the functional consequences of PTCHD1 locus deletions, we generated induced pluripotent stem cells (iPSCs) from unaffected controls and two ASD subjects with microdeletions affecting PTCHD1-AS/PTCHD1or PTCHD1-AS/DDX53. Function of iPSC-derived cortical neurons was assessed using molecular approaches and electrophysiology. We also compiled novel and known genetic variants of the PTCHD1 locus to explore the roles of PTCHD1 and PTCHD1-AS in genetic risk for ASD and other neurodevelopmental disorders. Finally, genome editing was used to explore the functional consequences of deleting a single conserved exon of PTCHD1-AS.