Abstract
FARS2, a nuclear gene, encodes the mitochondrial phenylalanyl-tRNA
synthetase (mtPheRS). Previous reports have described two distinct
phenotypes linked to FARS2 gene mutation: an early onset epileptic
encephalopathy and spastic paraplegia. This report describes a
distinctive phenotype of FARS2-linked, juvenile onset refractory
epilepsy, caused by a hemizygous mutation (p.V197M and exon 2
microdeletion). A 17-year- old woman with normal development presented
with a super refractory focal motor status epilepticus. Only an
emergency life-saving surgery aborted her status after all therapeutic
interventions, including anesthesia, failed to control her seizures.
Pathological and biochemical activities on muscle biopsy showed
mitochondrial proliferation with enhanced isolated activities of
complexes II and IV, suggestive of a compensatory mechanism for the
bioenergetic deficiency. Postoperatively, the patient started
experiencing focal aware motor seizures originating from the
contralateral hemisphere after being seizure free for a few months. This
report confirms a third phenotypic manifestation of FARS2 gene mutation.