Developmental and Epileptic Encephalopathy 8, also known as epileptic encephalopathy, early infantile, 8, is related to aicardi syndrome and developmental and epileptic encephalopathy 1, and has symptoms including reflex, abnormal and hyperexplexia. An important gene associated with Developmental and Epileptic Encephalopathy 8 is ARHGEF9 (Cdc42 Guanine Nucleotide Exchange Factor 9), and among its related pathways/superpathways is Ectoderm differentiation. Affiliated tissues include brain, and related phenotypes are developmental regression and hypertonia