We found 1 case of right kidney agenesis, which is consistent with previous reports that STXBP1 copy number variations are associated with kidney abnormalities.[17,18] In addition, we 1st reported 1 case of testicular hydrocele and 1 case of foot varus deformity in STXBP1-encephalopathy, and their pathogenic correlation needs to be verified by more cases. This evidence concerns the gene STXBP1 and testicular hydrocele.