For the unique negative interactions of btn1102–208del, where introduction of this mutation into cells deleted for another gene causes these cells to become synthetically sick, the interacting genes are linked to eye diseases (gal1, aim22, fab1, ath1, rad24), epilepsies (tef103, rad24), inherited inborn mitochondrial (hem25, mss1), neurological (sst2, rav1) immune system (ski3) and lipid metabolism (erg32) disorders. The gene discussed is PIKFYVE; the disease is epilepsy.