Motor Neurone Disease
STR: RFC1_CANVAS_ANNGN
PMID 38916676 reports three individuals from three families and PMID 38324175 reports three siblings from one family, all with biallelic RFC1 repeat expansions (AAGGG or ACAGG) presenting with adult‑onset motor neuron disease (ALS/PLS or motor neuronopathy) often accompanied by sensory neuropathy, cerebellar ataxia or vestibular deficits.Created: 22 Sep 2026, 10 p.m. | Last Modified: 22 Sep 2026, 10 p.m.
Panel Version: 2.17
Multiple apparently pathogenic expansions now reported (AGGGC, AAGGC, AGAGG, AAAGG, ACAGG) other than the common AAGGG expansionCreated: 25 Apr 2025, 11:24 a.m.
NM_001204747.1:c.132+2923_2927AAAAG[X]
Simple tandem repeat (AAAAG)n replaced with (AAGGG)n in intron 2 of RFC1. Loss of function is not the mechanism of disease. Maori population-specific CANVAS configuration (AAAGG)10-25(AAGGG)exp. (AAAGG)n repeat alone is not pathogenic. Mechanism of disease is unknown.
Normal: AAAAG 11 repeats (allele frequency = 0.75); AAAAG 12-200 (allele frequency = 0.13); AAAGG 40-1000 (allele frequency = 0.08)
Pathogenic: AAGGG repeat expansion, most frequently ranging from 400 to more than 2000 repeats (allele frequency = 0.01-0.04)
Sources: Expert listCreated: 29 Aug 2021, 4:30 p.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome MONDO:0044720
Publications
Str: rfc1_canvas_anngn has been classified as Green List (High Evidence).
Publications for STR: RFC1_CANVAS_ANNGN were set to 30926972; 32851396; 33237689; 31230722; 33237689; 32694621; 33103729; 35355059
STR: RFC1_CANVAS_ANNGN was added STR: RFC1_CANVAS_ANNGN was added to Motor Neurone Disease. Sources: Expert Review Green,Expert list adult-onset tags were added to STR: RFC1_CANVAS_ANNGN. Mode of inheritance for STR: RFC1_CANVAS_ANNGN was set to BIALLELIC, autosomal or pseudoautosomal Publications for STR: RFC1_CANVAS_ANNGN were set to 30926972; 32851396; 33237689; 31230722; 33237689; 32694621; 33103729; 35355059 Phenotypes for STR: RFC1_CANVAS_ANNGN were set to Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome MIM#614575