A targeting vector disrupted two genes via homologous recombination. Regulatory sequences and the first 7 exons of the Cntnap1 gene were replaced with a neomycin resistance cassette, as were the first two coding exons of the Ccr10 gene. Loss of Cntnap1 gene expression in homozygous mutants was demonstrated by Western blot analysis of whole brain and sciatic nerve homogenates and by immunohistochemistry of sciatic nerves and CNS. Effects on Ccr10 gene expression were not examined though the mutation was predicted to be a null allele due to the removal of the transcription start site for the gene.