Pathogenic expansions range from 400 to 2750 repeat units.72, 76 Biallelic RFC1 expansions are relatively common in patients with neuropathy: 14.5% and 34% of genetic diagnoses in two independent chronic idiopathic axonal polyneuropathy cohorts,77 78 and 25.3% and 72.7% of selected patients with HSAN.79 80 Since the initial discovery, additional polymorphic and pathogenic repeats, and loss-of-function SNVs have been identified.7576 81, 84. The gene discussed is RFC1; the disease is neuropathy.