Table 2 |.
SCAs caused by point mutations
| Disease | Gene | Mutation | Notable characteristic clinical signs |
|---|---|---|---|
| SCA5 | SPTBN2 | Missense | Downbeat nystagmus and some patients with spasticity, anticipation |
| SCA11 | TTBK2 | Missense | Some patients with pyramidal signs |
| SCA13 | KCNC3 | Missense | Variable between families |
| SCA14 | PRKCG | Missense | Tremor or myoclonus, facial myokymia |
| SCA15 and 16 | ITPR1 | Deletion | Pure cerebellar ataxia with tremor |
| SCA18 | IFRD1 | Missense | Sensorimotor neuropathy |
| SCA19 and 22 | KCND3 | Missense, in-frame 3bp deletion | Extracerebellar features variable between families |
| SCA20 | Multiple (DAGLA)a | 260kb duplication | Pure cerebellar ataxia with spasmodic dysphonia, palatal tremor |
| SCA21 | TMEM240 | Missense | Cognitive impairment, extrapyramidal signs |
| SCA23 | PDYN | Missense | Extracerebellar features variable between families |
| SCA26 | EEF2 | Missense | Pure cerebellar ataxia |
| SCA27 | FGF14 | Missense | Mental retardation, tremor |
| SCA28 | AFG3L2 | Missense | Spastic ataxia |
| SCA29 | ITPR1 | Missense | Pure cerebellar ataxia, congenital non-progressive |
| SCA34 | ELOVL4 | Missense | Hyperkeratosis, MSA-C-like |
| SCA35 | TGM6 | Missense | Hyperreflexia and variable other extracerebellar features |
| SCA38 | ELOVL5 | Missense | Pure cerebellar ataxia, some patients have sensory neuropathy |
| SCA40 | CCDC88C | Missense | Spastic ataxia |
| SCA41 | TRPC3 | Missense | Pure cerebellar ataxia |
| SCA42 | CACNA1G | Missense | Dementia |
| SCA43 | MME | Missense | Peripheral neuropathy |
| SCA44 | GRM1 | Missense, +1bp frameshift | Spasticity |
| SCA45 | FAT2 | Missense | Pure cerebellar ataxia (single family) |
| SCA46 | PLD3 | Missense | Sensory neuropathy |
MSA-C, multiple system atrophy of cerebellar type. Data were extracted from Online Mendelian Inheritance of Men (OMIM) and GeneReviews of corresponding SCAs.
aThe duplicated region in direct orientation contains 12 or more genes, including DAGLA.