By contrast, the profuse generation of RNA transcripts from the hexanucleotide-expanded C9orf72 gene in ALS and FTD neurons, which has been observed to cause the assembly and persistence within the cytosol of aggregated RNA tangles and foci, may supply significantly higher numbers of heme-binding and –activating sites within these cells. This evidence concerns the gene C9orf72 and frontotemporal dementia.