VNTRs and repeat expansions are of special interest as they have been heavily studied as functional variants and biomarkers in neurodegenerative diseases, as reported for the C9orf72 hexanucleotide and ataxin-1 and -2 repeat expansions associated with ALS and a VNTR within the ALS risk gene CFAP41040,41,49,50. The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.