This is a non-interventional longitudinal study of children and adults with Developmental and Epileptic Encephalopathy (DEE) due to a genetic cause. There are six arms of the study.
Arms 1, 2, and 3 are devoted to one example DEE, MEF2C Haploinsufficiency Syndrome (MCHS). Arms 4, 5, and 6 are open to all DEE.
Arm 1 (in-person) will enroll children 0 to 15, who will make in-person visits to Weill Cornell Medicine four times over two years.