Mitochondrial Complex I Deficiency Masquerading as Stroke-Like Episode Clinically and as Alexander Disease Radiologically Following Chicken Pox.

Mitochondrial disorders are a group of metabolic disorders with variable presentation and usually affect organs with high energy requirements like the brain, eye, and heart. Seventeen-month-old girl child presented with right hemiparesis and regression of milestones following chicken pox. Investigations showed elevated lactate, white matter signal changes in both periventricular and subcortical white matter with frontal predominance in the MRI of the brain, cardiomyopathy in the echocardiography, with complex I deficiency in respiratory enzyme assay in the muscle biopsy. A homozygous missense variant c.304C>T (p. Arg102Cys) in exon 5 of NDUFS8 gene (chr11:67800682C>T; NM_002496.4) was detected on whole exome sequencing with positive parental Sanger for the same gene. The child was started on a mitochondrial cocktail, ramipril, and frusemide. Mitochondrial complex deficiency should be considered in cases with stroke-like episodes, and predominant white matter involvement on imaging mimicking classical genetic leukodystrophy like Alexander disease.