COQ8B and kidney disorder: Most mitochondrial cytopathies are involved in multiple organ systems and often present with prominent neurologic and myopathic deficits in childhood.[1] Recent studies have found that mitochondrial dysfunction caused by genetic mutations in mitochondrial genes or nuclear genes can also lead to renal disease, for example, mitochondrial DNA A3243G mutation,[2]PDSS2 gene,[3]COQ2 gene,[4] and ADCK4 gene mutation.[5] Mitochondrial nephropathy has a poor prognosis and often leads to the end-stage renal disease.