Leigh Syndrome

---

Description

Leigh Syndrome is a rare and severe neurological disorder that affects the central nervous system. It is characterized by progressive neurological deterioration, typically starting in infancy or early childhood. While there is no cure for Leigh Syndrome, early diagnosis and management can help improve quality of life and maximize developmental potential.

Genes Involved

Leigh Syndrome is often linked to genetic mutations. While over 75 genes have been associated with the condition, some of the most common include:

• SURF1: Involved in the assembly of a key enzyme for cellular energy production.
• MT-ATP6: Encodes a subunit of the ATP synthase complex, essential for energy production in mitochondria.
• POLG: Encodes DNA polymerase gamma, responsible for DNA replication in mitochondria.
• SLC25A4: Transports pyruvate into mitochondria, a crucial step in energy production.
• DGUOK: Involved in the metabolism of deoxyguanosine, a nucleotide essential for DNA synthesis.

Recognizing the Signs and Symptoms

Recognizing the signs and symptoms of Leigh Syndrome is crucial for early intervention. Common symptoms include:

• Developmental delays: Slowed growth, difficulty reaching milestones, and impaired motor skills.
• Muscle weakness and hypotonia: Floppy limbs, difficulty with movement and coordination.
• Breathing difficulties: Shortness of breath, irregular breathing patterns, and respiratory failure.
• Feeding problems: Difficulty swallowing, poor sucking reflex, and failure to thrive.
• Seizures: Uncontrolled electrical activity in the brain, causing convulsions or other unusual behaviors.
• Vision and hearing loss: Impaired sight or hearing.
• Cognitive impairment: Delays in cognitive development and learning difficulties.
• Vomiting and diarrhea: Gastrointestinal issues that can contribute to malnutrition.
• Encephalopathy: Swelling of the brain, leading to altered mental status, confusion, and coma.

Causes

Leigh Syndrome is primarily caused by mutations in genes involved in mitochondrial function. These mutations disrupt the energy production process within cells, leading to a wide range of neurological symptoms.

Other potential causes include:

• Metabolic disorders: Conditions affecting the body‘s ability to process nutrients can also contribute to Leigh Syndrome.
• Environmental factors: Exposure to toxins or certain medications can trigger the onset of Leigh Syndrome in some individuals.

Inheritance/recurrence risk

The inheritance pattern of Leigh Syndrome varies depending on the underlying genetic mutation. Many cases are inherited in an autosomal recessive manner, meaning both parents must carry the gene mutation to pass it on to their child. In other cases, the mutation may be spontaneous or inherited in an autosomal dominant manner. The recurrence risk for families with Leigh Syndrome depends on the specific inheritance pattern and the genetic testing results.