C9orf72 and amyotrophic lateral sclerosis: FTD at diagnosis was present in 62 ALS patients (10.35%) among those who underwent genetic analysis; 72.58% of patients with FTD at diagnosis did not carry genetic mutations, whereas 22.58% had C9orf72 expansion (OR 6.34, p = 0.004) and 1.61% FUS mutation.