Table 1 summarizes the methods of identification of COL4A1/2 mutations in the cohort of new patients. Table 2 reports the phenotypes of previously-published patients with COL4A1/2 mutations and epilepsy. Tables 3a/b describes the clinical, EEG and brain MRI data of the new cohort of patients with COL4A1/2 mutations. Additional Method describes immunohistochemistry performed from consented surplus resected tissue from 1 case.