When investigating patients and choosing genetic testing for FTD-ALS, it is imperative to ensure that C9orf72 is being sequenced; it is not currently included in all targeted genetic testing panels for early onset dementia and may need to be specifically ordered with a sample sent to an alternate laboratory for Sanger Sequencing.24 Whole genome sequencing in contrast has been shown to detect most repeat expansions for these conditions,25,26 but is not yet widely clinically available. Here, C9orf72 is linked to amyotrophic lateral sclerosis.