CNTNAP2 and autism: To examine the effect of the essential α-secretase cleavage of CNTNAP2 on autism-like phenotypic behaviors, we generated mutant I1254T knock-in mice (Cntnap2-I1254T) using the CRISPR/Cas9 technique to express the I1254T mutant CNTNAP2 protein, corresponding to the pathogenic I1253T mutation in ASD patients (Fig. 5a).