[P3-156] Eyelid myoclonia with absences-like epileptic syndrome in a child with SYNGAP1 gene mutation
[Introduction] Eyelid myoclonia with absences (EMA) is one of the rare phenotype of epileptic syndrome. Caraballo et al. described 63 patients with EMA among 2,300 patients with idiopathic generalized epilepsy (2.7%) out of 11,285 with epilepsy (0.56 %) (Caraballo et al. Seizure. 2009). Whereas, 3 patients presented with eyelid myoclonia (18.7%) among 16 patients with SYNGAP1 gene mutation, but these were not assigned as EMA (Mignot et al. J Med genet. 2016).
[Case Report] We report a 4-year-old boy who developed recurrent eyelid myoclonia at 1 year 5 months of age. The seizures gradually increased in frequency to more than 50 times per day, which manifested with upward deviation of the eyes, motion arrest, loss of consciousness and eyelid twitching lasting up to 5 seconds. Ictal electroencephalography showed rhythmic generalized slow or spike and wave complex activity. Moderate psychomotor developmental delay and unsteady gate were also noted. The seizures were refractory to carbamazepine and levetiracetam but were reduced in frequency by ethosuximide and lamotrigine. Genetic analysis identified a heterozygous mutation in the SYNGAP1 gene.
[Discussion] Seizure phenotype of the present patient resembled that of eyelid myoclonia with absences (EMA). However, early seizure onset and intellectual disability in the patients with SYNGAP1 were uncommon as EMA. SYNGAP1 gene analysis should be considered for the patient with early onset eyelid myoclonia with/without absences and intellectual disability.
[Case Report] We report a 4-year-old boy who developed recurrent eyelid myoclonia at 1 year 5 months of age. The seizures gradually increased in frequency to more than 50 times per day, which manifested with upward deviation of the eyes, motion arrest, loss of consciousness and eyelid twitching lasting up to 5 seconds. Ictal electroencephalography showed rhythmic generalized slow or spike and wave complex activity. Moderate psychomotor developmental delay and unsteady gate were also noted. The seizures were refractory to carbamazepine and levetiracetam but were reduced in frequency by ethosuximide and lamotrigine. Genetic analysis identified a heterozygous mutation in the SYNGAP1 gene.
[Discussion] Seizure phenotype of the present patient resembled that of eyelid myoclonia with absences (EMA). However, early seizure onset and intellectual disability in the patients with SYNGAP1 were uncommon as EMA. SYNGAP1 gene analysis should be considered for the patient with early onset eyelid myoclonia with/without absences and intellectual disability.