Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (commonly referred to as LBSL) is a progressive disorder that affects the brain and spinal cord. Leukoencephalopathy refers to abnormalities in the white matter of the brain, which is tissue containing nerve cell fibers (axons) that transmit nerve impulses.

Most affected individuals begin to develop movement problems during childhood or adolescence. However, in some individuals, these problems do not develop until adulthood. People with LBSL have abnormal muscle stiffness (spasticity) 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, although 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.

Distinct changes in the brains of people with LBSL can be seen using magnetic resonance imaging (MRI). These characteristic abnormalities typically involve particular parts of the white matter of the brain and specific regions (called tracts) within the brainstem and spinal cord, especially the pyramidal tract and the dorsal column. In addition, most affected individuals have a high level of a substance called lactate in the white matter of the brain, which is identified using another test called magnetic resonance spectroscopy (MRS).

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

LBSL is caused by mutations in the DARS2 gene, which 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 centers in cells. While most protein synthesis occurs in the fluid surrounding the nucleus (cytoplasm), some proteins are synthesized in the mitochondria.

During protein synthesis, in either the mitochondria or the cytoplasm, building blocks (amino acids) are connected together in a specific order, creating a chain of amino acids that forms the protein. Mitochondrial aspartyl-tRNA synthetase plays a role in adding the amino acid aspartic acid at the proper place in mitochondrial proteins.

Mutations in the DARS2 gene result in decreased mitochondrial aspartyl-tRNA synthetase enzyme activity, which hinders the addition of aspartic acid to mitochondrial proteins. It is unclear how the gene mutations lead to the signs and symptoms of LBSL. Researchers do not understand why reduced activity of mitochondrial aspartyl-tRNA synthetase specifically affects certain parts of the brain and spinal cord.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

LBSL is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. In this condition, each copy of the gene carries a different mutation (compound heterozygous mutations). An affected individual never has the same mutation in both copies of the gene (a homozygous mutation). The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

LBSL is a rare condition. Its exact prevalence is not known.

Which doctor should you see?

The suggested department for discussing Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation is Neurology, with a neurologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.