ELP4 and Rolandic epilepsy: Elp1 is one of six subunits of the elongator holoenzyme, and in addition to the ELP1 mutation giving rise to FD, polymorphisms in four other subunit loci have been associated with neurologic diseases, including intellectual disability (ELP2, ELP4, ELP6), ALS (ELP3), and ASD and Rolandic epilepsy (ELP4)48–52.