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SUCLG1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SUCLG1 gene

The SUCLG1 gene provides instructions for creating the alpha subunit of an enzyme essential for cellular energy production and mitochondrial DNA maintenance.

Overview

The SUCLG1 gene provides instructions for making the alpha subunit of an enzyme called succinyl-CoA ligase. This alpha subunit is used to form two versions of the enzyme: one most active in high-energy tissues like the brain and muscle, and another active in tissues with lower energy requirements.

These enzymes function within the mitochondria, facilitating the citric acid cycle (or Krebs cycle) to produce energy. Furthermore, succinyl-CoA ligase interacts with nucleoside diphosphate kinase to maintain mitochondrial DNA (mtDNA), which is vital for cellular energy production.

Health Conditions Related to Genetic Changes

SUCLG1-related mitochondrial DNA depletion syndrome

Variants in the SUCLG1 gene cause this inherited disorder, which affects early brain development.

  • Mechanism: Most variants change a single amino acid in the alpha subunit, reducing but not eliminating enzyme activity. Individuals with some residual enzyme activity typically experience milder symptoms than those with no activity.
  • Impact: A deficiency of succinyl-CoA ligase leads to mtDNA depletion, which impairs energy production across many of the body's cells and tissues.

Leigh syndrome

The SUCLG1 gene is also associated with Leigh syndrome.

Other Names for This Gene

  • GALPHA
  • succinate-CoA ligase, ADP-forming, alpha subunit
  • succinate-CoA ligase, GDP-forming, alpha subunit
  • succinyl-CoA synthetase, alpha subunit
  • SUCLA1

Frequently Asked Questions

The condition often presents in early infancy with signs of impaired brain development, such as hypotonia (low muscle tone), developmental delay, and feeding difficulties. Because the enzyme deficiency affects energy production in high-demand tissues like the brain, parents may notice that the infant is unusually floppy, has poor head control, or fails to meet standard motor milestones. Seizures and progressive neurological decline are also common early indicators that prompt medical evaluation.
Yes, the severity of SUCLG1-related disorders is directly correlated with the amount of residual enzyme activity. Most variants change a single amino acid, which reduces but does not completely eliminate the function of the succinyl-CoA ligase alpha subunit. Individuals with some remaining enzyme activity typically experience milder symptoms and a slower disease progression compared to those with variants that result in no enzyme activity at all, who tend to have more severe and rapid neurological deterioration.
The SUCLG1 gene encodes the alpha subunit of succinyl-CoA ligase, an enzyme critical for the citric acid cycle. This enzyme also interacts with nucleoside diphosphate kinase, a protein essential for maintaining the pool of nucleotides required for mitochondrial DNA replication. When SUCLG1 function is impaired, this interaction is disrupted, leading to a shortage of nucleotides and subsequent depletion of mitochondrial DNA. This loss of mtDNA compromises the mitochondria's ability to produce energy, causing widespread cellular dysfunction.
The condition is inherited in an autosomal recessive pattern, meaning an individual must inherit two mutated copies of the SUCLG1 gene, one from each parent, to be affected. Parents who are carriers typically do not show symptoms but have a 25% chance with each pregnancy of having a child with the disorder. Genetic counseling and carrier testing are recommended for families with a history of the condition to assess risks and discuss reproductive options.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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