C9ORF72 repeat expansions not detected in a group of patients with schizophrenia.

A hexanucleotide repeat expansion in C9ORF72 was recently found to cause some cases of frontotemporal lobar degeneration, frontotemporal dementia (FTD)-amyotrophic lateral sclerosis, and amyotrophic lateral sclerosis. Patients with frontotemporal lobar degeneration with the C9ORF72 repeat expansion are more likely than those without to present with psychosis. In this study, we screened DNA samples from 192 unrelated subjects with schizophrenia for the C9ORF72 repeat expansion. None of the subjects with schizophrenia had the pathogenic expansion. C9ORF72 repeat expansions either do not cause schizophrenia, or do so rarely (less than 1% of cases).