99.5% of all FD patients, including the patient’s cells analyzed here29, harbor a homozygous mutation in ELP1. To examine whether hyperactivity is the direct consequence of the ELP1 mutation, we first performed symN differentiations using an ELP1 rescued line, iPSC-EPL1rescued-T6, in which the ELP1 mutation is heterozygously corrected by CRISPR-cas9 from the iPSC-FD-S2 line29. Here, ELP1 is linked to Fabry disease.