Table 3.
Summary of clinical findings in 25 cases of confirmed SCA‐PRKCG given as proportion (%) of sample with specific findings, ordered by possible structural attribution.
| Structure | System | Sign | Observed or reported (% of sample) | n = 25 unless stated otherwise |
|---|---|---|---|---|
| Cerebellum | Cerebellar ataxia (SARA ratings > 0) | Gait ataxia | 25 (100) | |
| Stance ataxia | 21 (84) | |||
| Dysarthria | 23 (92) | |||
| Limb ataxia | 25 (100) | |||
| Cerebellar oculomotor signs | Saccadic pursuit | 25 (100) | ||
| Saccadic dysmetria | 24 (96) | |||
| Gaze‐evoked nystagmus | 15 (60) | |||
| Non‐ataxia movement disorder, observed or reported | Myoclonus | 10 (40) | ||
| Dystonia | 8 (32) | |||
| Tremor | 3 (12) | |||
|
Other symptoms or signs of suspected cerebellar attribution |
Diplopia | 11 (44) | ||
| Dysphagia | 12 (48) | |||
| Mild cognitive impairment by clinical suspicion or subjective complaint | 11 (44) | |||
| Cognitive screening test positive | 6 (25) | (n = 24) | ||
| Brainstem |
Brainstem oulomotor signs |
Ophthalmoparesis | 0 | |
| Slowing of saccades | 0 | |||
| Retina/optic nerve | Symptoms or signs of retinal/optic nerve involvement | Reduced visual acuity (monocular) | 0 | (n = 13) |
| Optical coherence tomography pRNFL reduction | 0 | (n = 13) | ||
| Spinal tract | Symptoms or signs of pyramidal involvement | Hyperreflexia | 5 (20) | |
| Spasticity | 0 | |||
| Plantar extensor | 0 | |||
| Electrophysiology: CMCT abnormal | 0 | (n = 8) | ||
| Symptoms or signs of spinal or peripheral involvement | Fasciculations | 5 (20) | ||
| Muscle atrophy | 4 (16) | |||
| Pareses | 3 (12) | |||
| Reduced vibration sense (ankle) | 4 (16) | (n = 25) | ||
| Electrophysiology: mild neuropathy | 8 (44) | (n = 18) | ||
| Electrophysiology: SSEP abnormal | 5 (33) | (n = 15) | ||
| Undefined | Symptoms of unclear attribution | Depression/anxiety screening test positive | 11 (48) | (n = 23) |
| Depression/anxiety clinically relevant | 5 (22) | (n = 23) | ||
| Cramps or sensation of muscle stiffness | 10 (40) | |||
| Pain in legs or lower back unpexplained otherwise | 5 (20) |
CMCT, central motor conduction time; PRKCG, protein kinase C gamma; pRNFL, peripapillary retinal nerve fiber layer; SARA, scale for the assessment and rating of ataxia; SSEP, somatosensory‐evoked potentials; VUS, variant of uncertain significance.