These gene mutations included: ATP1A3 (associated with the expanding phenotypic spectrum of alternating hemiplegia of childhood, rapid-onset dystonia-parkinsonism, CAPOS and FIPWE) [18], POLG (mitochondrial depletion syndrome), NPC1 (Niemann–Pick disease, type C1), TUBB4A (DYT4), MTTP (abetalipoproteinemia), SPG7 –(spastic paraplegia 7) and SLC2A1 (GLUT1 deficiency syndrome). The gene discussed is POLG; the disease is abetalipoproteinemia.