Table 1.

Disease	Locus	Premutation/reduced penetrance	Full Mutation repeat threshold
Spinal and bulbar muscular atrophy	AR	35–37	38
Dentatorubral-pallidoluysian atrophy	ATN1	35–47	48
Spinocerebellar ataxia 1	ATXN1	39–43	44
Spinocerebellar ataxia 2	ATXN2	33–34	35
Spinocerebellar ataxia 3	ATXN3	45–59	60
Spinocerebellar ataxia 7	ATXN7	34–36	37
C9orf72-related Frontotemporal dementia and/or amyotrophic lateral sclerosis 1	C9orf72	-	31
Spinocerebellar ataxia 6	CACNA1A	19	20
Myotonic dystrophy 1	DMPK	35–49	50
Friedreich ataxia	FXN	45–65	66
Huntington disease	HTT	36–39	40
Huntington disease-like 2	JPH3	29–39	40
Oculopharyngodistal myopathy 3; Neuronal intranuclear inclusion disease (NIID)	NOTCH2NLC	41–55	56
Spinocerebellar ataxia 12	PPP2R2B	32–65	66
Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome	RFC1	-	1042 (median number of repeats)56 IQR=844–1306 range=249–3885
Spinocerebellar ataxia 17	TBP	41–48	49