In a large study of consanguineous families with autism, a homozygous deletion of SCN7A gene was identified in one family, which is adjacent to SCN1A gene within the sodium channel gene cluster (SCN1A, SCN2A, SCN3A, and SCN9A) on chromosome 2 (Morrow et al., 2008; Table 3). The gene discussed is SCN1A; the disease is autism.