HCCS and McLeod neuroacanthocytosis syndrome: The reduction in cytochromes content was paralleled by a decrease in the respiratory activity of the B-8025-Δcyc3 strain expressing either the HCCS mutant alleles or the pYEX empty vector (Supporting Information Fig S1B), indicating that the mutated HCCS alleles identified in MLS patients are pathogenic via impaired OXPHOS.