Here, we report the case of a patient with a novel homozygous truncating mutation in KCNMA1 (p.Arg458Ter) presenting with both the loss- and gain-of-function phenotype with paroxysmal dyskinesia, epilepsy, intellectual delay, and corticospinal–cerebellar tract atrophy.
This report extends the KNCMA1 mutation phenotype with a patient who carries a novel frameshift variant, presenting with both the gain- and loss-of-function phenotypes along with spinal tract involvement as a novel characteristic.