In addition, in primary skin fibroblasts obtained from Leigh syndrome patients with isolated complex I deficiency, abnormalities in mitochondrial membrane potential, ROS levels, and intracellular ATP content were closely associated with mutations in the nuclear-encoded complex I genes, including Ndufs7, Ndufs8, and Ndufv130. This evidence concerns the gene NDUFS8 and hyperinsulinemic hypoglycemia, familial, 4.