The syndrome caused by mutations in the DARS2gene — leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) — is a disorder characterized by slowly progressive unsteadiness (cerebellar ataxia), spasticity and disturbed position and vibration sense, caused by involvement of the cerebral white matter, brain stem and the long tracts of the spinal cord. Onset is usually in childhood or adolescence, but ranges from before birth to adulthood.
Marc Engelen, MD, PhD, Amsterdam Leukodystrophy Center, Department of (Pediatric) Neurology, Amsterdam UMC, The Netherlands, m.engelen@amsterdamumc.nl