Table 1.
Phenotypic characteristics of the 5 patients with AOA2.
| Family | Patient | Nucleotide change (exon) | Age at onset | Disease duration | Initial symptom | Oculomotor phenotype | Tendon reflexes | Deep sensory loss | Functional score | ICARS total (/100) | MMSE (/30) | FAB (/18) | EMG | AFP level | Height (cm) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I | I-1 | 5413C > T (10) | 18 | 10 | Gait ataxia, writing ataxia, dysarthria | Gaze-evoked nystagmus, saccadic smooth pursuit, absent fixation inhibition of VOR and staircase hypometric saccades (oculomotor apraxia) *For family I: additional positional induced central vestibular nystagmus and vestibulo-ocular hyper-reflexia |
Abolished | Present | 5 | 69 | 29 (draw) | 18 | Axonal sensory–motor neuropathy | 60 | 168 |
| I | I-2 | 12 | 14 | Dysarthria | Abolished | Present | 4 | 50 | 29 (write) | 17 (luria) | Axonal sensory–motor neuropathy predominant in sensory | 45.9 | 180 | ||
| II | II-1 | 7267G > A (23) | 20 | 17 | Gait ataxia | Abolished | Present | 6 | 69 | 24/28 (write, calculation) | 13 | Axono-myelinic neuropathy | 22.5 | 171 | |
| II | II-2 | 17 | 24 | Gait ataxia | Abolished | Present | 6 | 68 | 24 (calculation) | 18 | ND | 15 | 158 | ||
| III | III-3 | 6292C > T (15) | 12 | 30 | Gait ataxia | Periodic alternating nystagmus | Abolished | Present | 6 | 56 | 29 (reminder) | 17 (fluency) | ND | 79 | 176 |
Functional score of motor disability was assessed by a seven-stage functional scale: 0 = normal; 1 = mild modifications at examination; 2 = mild functional disability, able to walk and run; 3 = able to walk without help up to 500 m, unable to run; 4 = needs unilateral help to walk; 5 = needs bilateral help to walk; 6 = wheelchair-bound; 7 = bedridden. ICARS total, Mini mental state examination (MMSE), Frontal assessment battery (FAB), electromyogram (EMG), Alpha-Fetoprotein (AFP) levels. ND: no data.