Mutations in the P-type copper transporting ATPase, ATP7A, results in severe hereditary copper deficiency known as Menkes disease. Menkes follows an X-linked recessive inheritance pattern with male newborns exhibiting symptomatic illness. Menkes patients present with various hair and connective tissue abnormalities, failure to thrive, severe neurodegeneration, and death typically before three years of age. In the brain, copper deficiency impairs the function of cytochrome c oxidase, a component of mitochondrial electron transport required for energy generation.