Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL)


Autosomal recessive

Inheritance from both parents will result in the disease

Age range at onset:

Usually childhood or adolescence, sometimes adulthood

Specialists you may see:


LBSL is a progressive disorder that affects the brain and spinal cord. Most present with move-ment problems during childhood or adolescence. They have abnormal muscle stiffness (spastici-ty) and difficulty with coordinating movements (ataxia). In addition, affected individuals lose the ability to sense the position of their limbs or vibrations with their limbs. These movement and sensation problems affect the legs more than the arms, making walking difficult. Most affected individuals eventually require wheelchair assistance, sometimes as early as their teens, alt-hough the age varies.

People with LBSL can have other signs and symptoms of the condition. Some affected individuals develop recurrent seizures (epilepsy), speech difficulties (dysarthria), learning problems, or mild deterioration of mental functioning. Some people with this disorder are particularly vulnerable to severe complications following minor head trauma, which may trigger a loss of consciousness, other reversible neurological problems, or fever.


Mutations of the DARS2 gene cause LBSL. DARS2 gene provides instructions for making an enzyme called mitochondrial aspartyl-tRNA synthetase. This enzyme is important in the production (synthesis) of proteins in cellular structures called mitochondria, the energy-producing centres in cells. While most protein synthesis occurs in the fluid surrounding the nucleus (cytoplasm), some proteins are synthesized in the mitochondria.

LBSL presents with similar symptoms to Hypomyelination with brainstem and spinal cord in-volvement and leg spasticity.