Table 1:

Summary of clinical and epilepsy characteristics by variant type

Clinical Characteristic	All variants, n = 24	LoF variants*, n = 20	Missense variants, n = 4
Neurodevelopmental disability	24 (100 %)	19 (100 %)	4 (100 %)
Developmental regression	2 (8.33 %)	2 (10 %)	0
Autistic features or Autism	12 (50 %)	10 (50 %)	2 (50 %)
Microcephaly or borderline microcephaly	3 (12.50 %)	3 (15 %)	0
Epilepsy	15 (62.50 %)	12 (60 %)	3 (75 %)
Epilepsy Characteristic	All variants, n = 15	LoF variants, n = 12	Missense variants, n = 3
Age of epilepsy onset
< 1 year	2 (13.33 %)	2 (16.67 %)	0
1-4 years	11 (73.33 %)	8 (66.67 %)	3 (100 %)
> 4 years	2 (13.33 %)	2 (16.67 %)	0
Generalized seizures	12 (80 %)	10 (83.33 %)	2 (66.67 %)
Myoclonic	7 (46.67 %)	6 (50 %)	1 (33.33 %)
Atonic and/or myoclonic-atonic	5 (33.33 %)	5 (41.67 %)	0
Absence or atypical absence	5 (33.33 %)	5 (41.67 %)	0
Tonic, clonic and/or tonic-clonic	10 (66.67 %)	8 (66.67 %)	2 (66.67 %)
Focal and generalized seizures	4 (26.67 %)	2 (16.67 %)	2 (66.67 %)
Focal seizures only	1 (6.67 %)	0	1 (33.33 %)
Unclassified seizures only	2 (13.33 %)	2 (16.67 %)	0
Epileptiform abnormalities on EEG
Generalized spike/polyspike and wave	9 (60 %)	8 (66.67 %)	1 (33.33 %)
Focal and generalized discharges	1 (6.67 %)	1 (8.33 %)	0
Focal discharges	2 (13.33 %)	1 (8.33 %)	1 (33.33 %)
Unclassified discharges	2 (13.33 %)	2 (16.67 %)	0
No epileptiform abnormalities	1 (6.67 %)	0	1 (33.33 %)

^*All deletions, frameshift, nonsense and splice-site were considered loss of function (LoF) for this table