Epilepsy, Early-Onset, 2, with or Without Developmental Delay, also known as epilepsy, early-onset, with or without developmental delay, is related to early-onset epilepsy 2. An important gene associated with Epilepsy, Early-Onset, 2, with or Without Developmental Delay is SETD1A (SET Domain Containing 1A, Histone Lysine Methyltransferase). Affiliated tissues include brain and testis, and related phenotypes are bilateral tonic-clonic seizure and hydrocele testis