TABLE 2.
Epilepsy syndromes diagnosed before age 7 years
| Epilepsy syndrome |
Onset age <12 mo |
All cases, onset age <24 mo, n (%) |
Birth prevalence | |
|---|---|---|---|---|
| n (%) | Incidence (95% CI) | |||
| West syndrome | 31 (35) | 49 (34‐69) | 33 (28) | 1/2100 |
| Lennox‐Gastaut syndrome | 10 (11) | 16 (8‐29) | 10 (8.6) | 1/6900 a |
| EIMFS | 2 (2.3) | 2 (1.7) | ||
| Dravet | 1 (1.1) | 1 (0.9) | ||
| GEFS+ | 0 | 4 (3.4) | ||
| Myoclonic atonic epilepsy | 0 | 1 (0.9) | ||
| Benign familial infantile epilepsy | 5 (5.7) | 7.9 (3.3‐19) | 5 (4.3) | 1/13,900 |
| Benign infantile epilepsy | 13 (15) | 20 (12‐35) | 13 (11) | 1/5,300 |
| Benign neonatal epilepsy | 1 (1.1) | 1 (0.9) | ||
| Myoclonic epilepsy in infancy | 1 (1.1) | 1 (0.9) | ||
| Any epilepsy syndrome | 56 (64) | 88 (68‐115) | 63 (54) | 1/1,100 a |
| No syndrome | 32 (36) | 50 (36‐71) | 53 (46) | |
| Total | 88 (100) | 139 (112‐171) | 116 (100) | |
Onset refers to the first unprovoked seizure, not necessarily syndrome onset. CI, confidence interval; EIMFS, epilepsy of infancy with migrating focal seizures; GEFS+, genetic epilepsy with febrile seizures plus; n, number of cases (% of all cases). Incidence: cases/100 000 person‐years. Birth prevalence rounded to nearest hundred.
a
Potentially underestimations because Lennox‐Gastaut syndrome and some other syndromes may have seizure onset >24 mo of age.