TABLE 2. Paediatric disorders with chronic ataxia in which neuro-ophthalmological signs (N-OS) occur frequently are displayed with the commonest N-OS and their frequencies.
| Disorders with at least five patients | Number of patients with N-OS/Total number of patients with the disorder (%) | Commonest N-OS | Number of patients with the commonest N-OS |
|---|---|---|---|
| Hypoxic-ischaemic encephalopathy following birth | 5/5 (100) | Strabismus | 4 |
| Episodic ataxia* | 6/7 (85.7) | Nystagmus | 5 |
| Neuronal ceroid lipofuscinosis‡ | 5/6 (83.3) | Abnormal optic discs | 5 |
| Joubert syndrome–related disorders | 4/5 (80) | Strabismus | 4 |
| Neuronal migration disorder | 4/5 (80) | Strabismus | 4 |
| Ischaemic stroke† | 7/9 (77.8) | Nystagmus | 6 |
| Friedreich ataxia | 5/7 (71.4) | Hypometric saccades/ impaired SP/nystagmus | 2 for each sign |
| Mitochondrial disease | 6/9 (66.7) | Strabismus/nystagmus | 2 for each sign |
| Severe epilepsy syndrome | 3/5 (60) | Impaired visual acuity | 2 |
| Ataxia telangiectasia | 6/13 (46.2) | Impaired SP | 4 |
| Angelman syndrome | 5/16 (31.3) | Strabismus | 3 |
SP = smooth pursuit.
*Acetazolamide-responsive episodic ataxia, proven on DNA testing in three patients, whereas the other four patients have positive family history of episodic ataxia that was not confirmed on DNA testing.
‡Consists of five patients with types 1 and 2 and one patient with type 3.
†Consists of one prenatal and eight postnatal thrombo-embolic and vasculitic aetiologies.