Figure. Patient's pedigree, paraclinical tests, and novel NDUFS4 gene mutation.

(A) Pedigree of the proband III1. (B) Patient brain MRI. T2-weighted MRI showed bilateral posterior putaminal atrophy and hyperintensities. (C) Mitochondrial respiratory enzyme activities of muscle and fibroblasts from the NDUFS4 patient and controls. Mitochondrial respiratory chain and citrate synthase (CS) activities were determined by spectrophotometric analysis. CS activity is expressed in nanomoles per minute per milligram. Mitochondrial respiratory chain data are expressed as the ratio of complexes/CS activities. (D) Blue native polyacrylamide gel (BN-PAGE) analysis from NDUFS4 patients: a proband and a patient with severe Leigh syndrome carrying nonsense mutations (c.262C>T; p.Gln88X and c.316C>T; p.Arg106X) and control using antibodies against NDUFB6 and NDUFS3 subunits detecting complex I and SDHA (70 kDa) revealing complex II. Primary fibroblasts were cultured from the patient and controls, and BN-PAGE analysis was performed as described elsewhere.⁷ (E) Identification of the c.369C>A mutation in the proband compared with wild-type and interspecies amino acid comparison, showing that the asparagine (N) at position 123 is highly conserved (in orange).