The Epi4K study. 165 patient-parent trios with Infantile Spasms and Lennox-Gastaut Syndrome were subjected to exome sequencing. The researchers found many known epilepsy genes, several single hits and some double hits. In summary, their data explains 15% of cases with IS/LGS. Taken together, 25% of cases can be explained through CNVs of single-gene mutations.