In our study, although no statistical significance was found, drug-refractory epilepsy showed a trend of increased incidence in the positive genetic test group compared with the negative genetic test group, which was likely because drug-refractory epilepsy was more likely have a genetic etiology, such as has been reported for PCDH19 (20) and SCN1A gene mutations (21), which carry a greater risk of drug-refractory epilepsy. Here, PCDH19 is linked to epilepsy.