RFC1 and Tay-Sachs disease: Excluding patients with variants of unknown significance, 17 patients had a biallelic expansion in FXN (Friedreich’s ataxia), 8 a biallelic expansion in RFC1 (Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome, CANVAS), 7 had biallelic variants in SACS (ARSACS), 6 biallelic variants in SYNE1 (SCAR8), 5 biallelic variants in SETX (AOA2) and 9 had rarer forms (4 patients with Tay Sachs disease, 3 patients with 4H-Syndrom and 2 patients with SCAR17).