Homozygous null mutations in DMXL2 are associated with Ohtahara syndrome, a progressive epileptic encephalopathy65, and homozygous null mutations in ROGDI cause Kohlschütter–Tönz syndrome, a condition marked by enamel formation defects, seizures, severe developmental delays and intellectual disability24,66. The gene discussed is DMXL2; the disease is early-infantile DEE.