TABLE 1A.
Clinical features and previous treatments.
| Patient No/current age/sex | CHD2 Gene alteration | Age of onset/type of first seizure | Seizure types | Cognitive development before seizures | Currently intellectual disability/autism spectrum disorder | Age ataxia | ASM used |
|---|---|---|---|---|---|---|---|
| 1/14/F |
c.1934C > A pathogenic missense |
6/Eyelid fluttering | Upward deviation of eyes/eyelid fluttering, evaluated as myoclonic | Borderline at 3 | Severe/Yes | 5 | ESX, LZP |
| 2/8/M |
c.236 T > C missense VUS |
2/Myoclonic jerks | Myoclonic jerks, eyelid myoclonus | Normal | No/No | No | CZP, ESX |
| 3/8/F |
c.2647_2649 Del in‐frame VUS |
6/Staring, then loss of consciousness | Absence with hypersalivation and oral automatisms, with postictal confusion and inability to communicate, myoclonic jerks, eyelid myoclonus | Mild speech disability | Mild/No | No | LEV, CBZ |
| 4/14/F |
c.3774Dup (p.Tyr1246IllfsTer13) likely pathogenic frameshift |
2/Febrile convulsive seizure | Myoclonic seizures, GTCS | Mild disability | Mild/No | No | CBZ, LEV, VPA |
| 5/17/M |
CHD2‐c.4176_4177Del pathogenic frameshift |
2y/Febrile convulsive seizure | GTCS, eyelid myoclonus | Normal | Moderate/Yes | 3 | VPA. LEV, CBZ |
| 6/13/F |
c.1717dupA likely pathogenic frameshift |
4/GTCS |
Myoclonic‐atonic seizures, oro‐alimentary automatisms, GTCS Comment: Spontaneous seizures stopped on LEV, Before ACZ treatment, only myoclonic seizures on IPS |
Mild disability from birth | Mild disability/No | No | LTG, VPA, LEV |
| 7/10/F |
c.1453C > T pathogenic nonsense |
3/Eyelid myoclonus | Eyelid myoclonus, GTCS | Disability from first year | Mild/Yes | No | VPA, ESX, CBD, LEV |
| 8/6/M |
c.294 + 1G > A noncoding likely pathogenic |
1/Myoclonic jerks | Myoclonic jerks, eyelid myoclonus | Disability from first year | Mild/No | No | LEV, VPA |
| 9/15/F |
c.1143_1146delAAGA p.Glu381fs likely pathogenic nonsense |
1/Eyelid myoclonus | Eyelid myoclonus, GTCS | Disability from first year | Mild/No | No | VPA, LEV |
| 10/4/F |
c.2686C > T pathogenic nonsense |
1.5/Absences with eyelid myoclonus | Absences with eyelid myoclonus | Moderate disability | Moderate/Yes | 1.5 | LEV, VPA, ESX |
| 11/9/F | Microdeletion chromosome 15 including exons 6–12 of the CHD2 gene | 7/Myoclonic jerks | Myoclonic jerks | Moderate disability | Moderate/Yes | 2 | VPA, LEV |
| 12/17/F |
c.5035C > T pathogenic nonsense |
6/Absences with eyelid myoclonus |
Absences with eyelid myoclonus, GTCS. Comment: Spontaneous seizures stopped on VPA, eyelid myoclonus remained on IPS |
Moderate disability | Moderate/Yes | No | VPA, LEV, TPM |
Abbreviations: ASM, antiseizure medication; CBD, cannabidiol; CLB, clobazam; CZP, carbamazepine; ESX, ethosuximide; F, female; GTCS, generalized tonic–clonic seizure; IPS, intermittent photic stimulation; LEV, levetiracetam; LTG, lamotrigine; LZP, lorazepam; M, male (Age is given in years); TPM, topiramate; VPA, valproate; ZNS, zonisamide.