Planar Cell Polarity Gene Mutations in Autism Spectrum Disorder, Intellectual Disabilities, and Related Deletion/Duplication Syndromes

In this chapter, we focus on inherited or de novo human mutations associated with autism spectrum disorder (ASD) or intellectual disability (ID) disorder, which involve members of the noncanonical planar cell polarity (PCP) pathway(s). Although most of these gene mutations give rise to multisystemic phenotypes, some mutations are involved in monogenic disorders. In the past 15 years, whereas they have been studied mostly in invertebrates, the involvement of PCP genes in numerous functions in mammals has been identified. Planar cell polarity genes have been implicated in brain development, sensory functions, synaptic plasticity, learning and memory, and social behavior, to cite a few. Thus, it is not surprising, given their impact on many crucial cellular functions, that by sequencing the exomes of ASD patients and their parents for studies of single nucleotide polymorphism association, global rare copy number variation, rare de novo variants, or de novo mutations, some PCP genes have emerged as susceptibility genes in ASD or ID syndromes and related pathologies.