Expression of either wild type Miro1 or Miro1E208K/E328K should rescue the effect of ALS mutant SOD1 on mitochondrial transport if the defect was caused by reduced levels of Miro1, but only Miro1E208K/E328K should rescue if the defect was Ca2+ dependent. The gene discussed is RHOT1; the disease is amyotrophic lateral sclerosis.