Table 1.
Phenotypic variability of cataplexy episodes in members of family 1 carrying KCNA1 mutations
| Affected family members | II:1 | II:2 | II:3 | III:2 | III:6 (proband) | III:7 |
|---|---|---|---|---|---|---|
| Gender/age in years (age of onset) | F/60 (childhood) | F/58 (childhood) | F/53 (childhood) | M/33 (10 years) | F/24 (5 years) | M/17 (5 years) |
| Isolated episodes | Present | Present | Present | Present | Present | Present |
| Features during isolated episodes | ||||||
| Imbalance | + | + | + | + | + | + |
| Slurred speech | + | + | + | − | + | +/− |
| Coordination difficulties in arms | + | + | + | − | + | − |
| Visual disturbance | − | + | + | − | + | + |
| Myokymia | − | + | − | − | + | − |
| Weakness | + | + | + | + | − | + |
| Stiffness | − | +/− | − | − | − | − |
| Dizziness/vertigo | − | + | + | + | − | − |
| Frequency of isolated episodes | ||||||
| Times per week during childhood (age <20 years) | 1–5 | 1–5 | 1–5 | 1–5 | Daily | 1–5 |
| During adulthood (times per week) | <1 | <1 | <1 | 1–5 | 1–5 | N/A |
| Duration of longest attack | 10 min. | 3–5 min. | 3–5 min. | 10 min. | 6–7 hrs. | 3–5 min. |
| Triggers for isolated episodes | ||||||
| Physical activity or exercise | − | + | + | − | + | + |
| Stress | + | + | + | + | + | + |
| Startle | − | + | + | + | + | + |
| Emotion | − | + | + | + | + | + |
| Illness/fever | + | + | + | +/− | + | + |
| Postural change (e.g., bending, standing up, looking down) | − | + | + | + | + | + |
| Environmental temperature | + | +/− | + | +/− | + | + |
| Health issues between episodes | ||||||
| Involuntary muscle contractions | − | − | + | + | + | − |
| Ataxia/difficulties with balance | − | − | + | − | − | − |
| Tremors | − | +/− | + | + | − | − |