C9orf72 and Huntington disease: In a series of one-off case reports, in patients with features of psychosis or schizophrenia, an empiric strategy of targeted sequencing of select genes known to be associated with neurological disorders identified rare, repeat expansions (for example, in HTT, ATXN8OS and C9orf72, known to be associated with Huntington’s disease (HD), hereditary ataxias, and amyotrophic lateral sclerosis, respectively) [35–39].