Likely, other unknown genetic mechanisms (modifier genes, epigenetics) or environmental influences could modify the epilepsy phenotype.17,29,31 Moreover, variants in the PRRT2 gene display pleiotropy, a high degree of variable expressivity, and incomplete penetrance (50%–90%).17,28 Understanding the spectrum of epilepsy in patients with PRRT2 variants is important when counseling patients and caregivers. This evidence concerns the gene PRRT2 and epilepsy.