Table 2.
Clinical features of the individuals with BSN variants
| Case | Variants (NM_003458.3) |
Gender | Seizure onset | Seizure course | Seizure outcome | Effective AEDs | EEG | Brain imaging | Development | Diagnosis |
| Case 1 | c.418C>T/p.Arg140Trp c.10817C>G/p. Ser3606Cys |
Male | Early adolescence | GTCS once, absence 1–2 times/day, myoclonus one time/2–3 months | Sz free 1 year | VPA, LEV | Generalised spike-and-wave discharges | Normal | Normal | IGE |
| Case 2 | c.1473G>C/p. Gln491His c.8464G>A/p. Val2822Met |
Male | Early childhood | FS once, CPS 1–2 times/night | Sz free 2 years | CBZ, CZP, VPA | Right centroparietal area discharges | Normal | Normal | PE |
| Case 3 | c.3196C>T/p.Arg1066Cys c.10573G>T/p. Gly3525Trp |
Female | Toddler | FS 5–6 times/year, then afebrile sGTCS twice/year since 5 years old | Sz free 2 years | LEV | Normal | Normal | Normal | EFS+ |
| Case 4 | c.4359-4361del/p.Leu1454del c.10925C>T/p. Ala3642Val |
Male | Toddler | sGTCS six times/week, CPS 11 times/month | Sz free 7 mos | LEV, LTG, VPA | Left frontal discharges and bilateral frontal–parietal slow activities | Normal | Developmental delay and microcephalus | PE |
| Case 5–1 | c.10559C>T/p. Pro3520Leu | Female | Infancy | FS at 1 year, afebrile GTCS 4 times/year since 14 years old | Sz free 9 years | TPM | Irregular generalised spike-and-slow waves | Normal | Normal | IGE |
| Case 5–2 (M) | c.10559C>T/p.Pro3520Leu | Female | Infancy | FS 3 times | Sz free | Untreated | NA | NA | Normal | FS |
| Case 6–1 | c.10972A>T/p.Thr3658Ser | Male | Infancy | FS 3–4 times/year, afebrile GTCS twice within 2 years | Sz free 1 year | LEV | Normal | Normal | Normal | EFS+ |
| Case 6–2 (F) | c.10972A>T/p.Thr3658Ser | Male | Infancy | FS once | Sz free | Untreated | NA | NA | Normal | FS |
| Case 7 | c.3322G>T/p.Glu1108Ter | Male | Toddler | FS 5–6 times/year | Sz free 3 year | Untreated | Normal | Normal | Normal | EFS+ |
| Case 8 | c.7351C>T/p.Gln2451Ter | Female | Infancy | FS 3–4 times/year, CPS 4 times/months since 3 years old | Sz free 9 months | LEV | Generalised spike-and-slow waves | Normal | Normal | EFS+ |
AED, antiepileptic drug; CBZ, carbamazepine; CPS, complex partial seizure; CZP, clonazepam; EFS+, epilepsy with febrile seizures plus; F, father; FS, febrile seizure; GTCS, generalised tonic–clonic seizure; IGE, idiopathic generalised epilepsy; LEV, levetiracetam; LTG, lamotrigine; M, mother; NA, not available; PE, partial epilepsy; sGTCS, secondary generalised tonic–clonic seizure; Sz, seizure; TPM, topiramate; VPA, valproate.