This conclusion is consistent with previous findings showing expansions of Vα2.3+Vβ22+ CD4+ T-cells in the presence of HLA-DRB1*03, irrespective of other features of LS (14), and highlights the necessity of a future classification of patients based on genetic and/or immunological features rather than symptomatic presentation. Here, HLA-DRB1 is linked to Leigh syndrome.