Identification of 19 individual CD4+ T cell clusters of different abundance between LS and non-LS patients:• LS patients had more expression of immunoregulatory molecules (CTLA4, PD1, ICOS+ TREGS)• Non-LS patients had higher expression of effector markers (HLADR, CD127, CD39, CD44). The gene discussed is CD44; the disease is Leigh syndrome.