A mouse mutation that dysregulates neighboring Galnt17 and Auts2 genes is associated with phenotypes related to the human AUTS2 syndrome

AUTS2 was originally discovered as the gene disrupted by a translocation in human twins with Autism spectrum disorder (ASD), intellectual disability, and epilepsy. Since that initial finding, AUTS2-linked mutations and variants have been associated with a very broad array of neuropsychiatric disorders, suggesting that AUTS2 is required for fundamental steps of neurodevelopment. However, genotype-phenotype correlations in this region are complicated, because most mutations could also involve neighboring genes. Of particular interest in this regard is the nearest downstream neighbor of AUTS2, GALNT17, encoding a brain-expressed N-acetylgalactosaminyltransferase of unknown brain function. Here we describe a mouse (Mus musculus) mutation, T(5G2;8A1)GSO (abbreviated 16Gso), a reciprocal translocation that breaks between Auts2 and Galnt17 and dysregulates both genes. Despite this complex regulatory effect, 16Gso homozygotes model certain human AUTS2-linked phenotypes very well. In addition to abnormalities in growth, craniofacial structure, learning and memory, and behavior, 16Gso homozygotes display distinct pathologies of the cerebellum and hippocampus that are similar to those associated with ASD and other types of neurological disease associated with this genomic region. Analyzing the mutant cerebellar and hippocampal transcriptomes, we identified disturbances in pathways related to neurite and synapse maturation, neurotransmitter signaling, and cellular stress, suggesting possible cellular mechanisms for 16Gso phenotypes. These pathways, coupled with the translocation's selective effects on Auts2 isoforms and coordinated dysregulation of Galnt17, suggest novel hypotheses regarding the etiology of the human “AUTS2 syndrome” and the wide array of neurodevelopmental disorders linked to variance in this genomic region. Overall design: We collected cerebellum (CB) and hippocampus (HC) from 16Gso homozyotes and wild type (WT) animals at postnatal day 14 (P14) and P35. RNA from three animals of each genotype and age was used to generate Illumina RNA-seq libraries. We compared mutant and WT gene expression at each age in each tissue to identify differentially expressed genes.