In the present invention, intractable epilepsy accompanying severe intellectual disability and motor development retardation is detected by using a sample removed from a living organism to examine whether a mutation in gene GNAO1 is present in the living organism. Intractable epilepsy is detected in cases when a harmful mutation in at least one allele of gene GNAO1 is detected. In epilepsy cases where GNAO1 mutations are present, there are cases affiliated with involuntary movement, a symptom rare in ordinary epileptic encephalopathy, and thus the likelihood of involuntary movement can also be predicted using gene GNAO1 mutation as an index.
METHOD FOR DETECTING INTRACTABLE EPILEPSY ACCOMPANYING SEVERE INTELLECTUAL DISABILITY AND MOTOR DEVELOPMENT RETARDATION