The first evidence linking neuropsychiatric disorders to heterozygous deletions affecting α-neurexin I (NRXN1α) was the discovery of a de novo deletion of the promoter and exons 1–5 of NRXN1α in a 7-year old boy with autism (Friedman et al., 2006), and a deletion of the promoter and exon 1 in two schizophrenic siblings, inherited from their unaffected mother (Kirov et al., 2009). Here, NRXN1 is linked to autism.