Ohtahara syndrome is a clinical manifestation that is present in a heterogeneous group of epileptic encephalopathies.
Specifically, Ohtahara syndrome is the most severe variant of earlier-onset epileptic encephalopathies. The disease usually begins to manifest during the neonatal period or within a few months.
Ohtahara syndrome is characterized by the frequent occurrence of tonic seizures or spasms, which arise in childhood, during periods of sleep or wakefulness. EEG has a specific pattern, which shows peaks of high voltage discharge, alternating with periods of almost flat suppression. It has been observed that about 75% of individuals affected, progressing to a West syndrome phenotype characterized by a hypsarrythmic EEG, presence of tonic spasms and delayed psychomotor development.
Ohtahara syndrome is associated with alterations in a wide array of genes. Mutations have been reported in ARX (Xp21.3); CACNA2D2 (3p21.31), KCNQ2 (20q13.33); PLCB1 (20p12.3); SCN2A (2q24.3); SCN8A (12q13.13), SLC25A22 (11p15 .5); SPTAN1 (9q34.11) and STXBP1 (9q34.11). All of them are listed in our panel NGS.
The type of inheritance and prevalence of the disorder depends on the gene affected.