MLH1 and Leigh syndrome: Specifically, as regards the 19 probands with a molecular diagnosis of LS, six different PVs/LPVs in the MLH1 gene were identified in nine patients (47.4%), four different PVs/LPVs in the MSH2 gene were identified in four patients (21.1%), two different PVs in the MSH6 gene were identified in five patients (26.3%), and one PV in the PMS2 gene was identified in one patient (5.3%) (Table S1, Figure 2).