Studies have reported alpha-, and gamma- clustered protocadherins proteolysis by presenilins (Buchanan et al., 2010), whereas the non-clustered protocadherin-X, Y have been investigated as candidate genes for schizophrenia (Giouzeli et al., 2004; Kalmady and Venkatasubramanian, 2009). This evidence concerns the gene PCDH11X and schizophrenia.