neomorphic Pcdhg variants were detected in Pcdhgtcko/tcko mutants with splice junction analysis of the RNA-Seq data (Table S2). The striking phenotypic similarities in contrast to the vastly distinct Pcdh repertoires in Pcdhgtcko/tcko and Pcdhgdel/del mutants suggest that lack of the C-type Pcdhg isoforms themselves, which is common for both mutants, is the primary cause of the common phenotypes.