Interestingly, one group reported an ALS patient presenting with behavioural variant FTD who carried a loss-of-function splice site mutation (c.601 -2A > G) that created a premature stop codon (p.I201fsX235), resulting in reduced C9orf72 mRNA levels in leukocytes relative to control cases [31]. The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.