Leukoencephalopathy with thalamus and brainstem involvement and high lactate caused by novel mutations in the EARS2 gene in two siblings.

Leukoencephalopathy with thalamus and brainstem involvement, and high lactate (LTBL) is a recently identified disease related to mutations in the EARS2 gene encoding glutamyl-tRNA synthetase. We report clinical and radiological findings for two siblings with new pathogenic mutations in the EARS2 gene. Both patients showed symptoms of mild-type disease, but there were clinical differences between the two siblings. While the older brother had hypotonia and delayed developmental milestones, the younger brother had seizures and spasticity in the lower extremities. Brain magnetic resonance imaging (MRI) findings were quite similar for the two siblings. MRI findings were specific to LTBL. MRI lesions of the older sibling had regressed over time. Clinical and radiological improvement, as in the previously reported patients with LTBL, may be an important clue for diagnosis.