SERAC1 and deafness: As an example of proteins responsible for the impairment of mitochondrial respiration, we had the possibility to analyze in our laboratories the case of NDUFAF6, which plays a crucial role in the assembly of complex I [23] and SERAC1 responsible for the MEGDEL syndrome (3-methylglutaconic acidemia, deafness, encephalopathy and Leigh-like syndrome; https://www.omim.org/entry/614739, accessed on 8 April 2022), which shares with Leigh syndromes several phenotypic traits [163,164].