<i>NDUFS8</i> -Related Leigh Syndrome Mimicking a Leukodystrophy

Leigh syndrome is a progressive infantile neurodegenerative disorder of mitochondrial metabolism that often leads to decompensation in the setting of metabolic stress. It is genetically heterogenous with varied inheritance patterns. One subtype includes <i>NDUFS8-</i>related autosomal recessive Leigh syndrome. This nuclear gene encodes a complex I subunit of the mitochondrial complex chain. Although Leigh syndrome is typically associated with basal ganglia and brainstem involvement, cases of confluent white matter disease have been described with <i>NDUFS8</i>-related disorders. We present the case of a 6-month-old girl with initial imaging suggestive of a leukodystrophy, later found to have a novel homozygous variant in <i>NDUFS8</i>. In conjunction with the clinical course, a diagnosis of Leigh syndrome was made. This case highlights that mitochondrial disorders should be considered on the differential for confluent cerebral white matter disease in early childhood.