Whole exome sequencing from the patient and her parents (trio-based variant analysis) identified a single de novo variant within the epilepsy candidate genes, a heterozygous mutation GRCh37/hg19:chr16:56370645, NM_020988.2: c.596 T > C in GNAO1, producing the amino acid change p.Leu199Pro (NP_066268.1) in the proband. The gene discussed is GNAO1; the disease is epilepsy.