MLH1 and Leigh syndrome: Here, we report a novel MLH1 nonsense variant, NM_000249.4:c.856A>T/NP_000240.1:p.(Lys286Ter), associated with LS and classified as LP according to the joint consensus guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP)3.