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SARS2
seryl-tRNA synthetase 2, mitochondrial
SARS2 is located on the long (q) arm of chromosome 19, at band 19q13.2. Arm ratio per GRCh38 - banding schematic.
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Clinical tests that include this
Overview
The SARS2 gene encodes seryl-tRNA synthetase 2, a mitochondrial enzyme responsible for charging transfer RNA molecules with the amino acid serine during mitochondrial protein synthesis. This process is essential for producing the thirteen protein subunits of the electron transport chain that mitochondria encode themselves. Because mitochondria generate most of the cell's energy through oxidative phosphorylation, proper functioning of SARS2 is critical for cellular energy metabolism. Tissues with high energy demands, including the brain, heart, kidneys, and muscles, are particularly vulnerable to disruptions in mitochondrial protein synthesis.
What the gene does
Seryl-tRNA synthetase 2 belongs to the aminoacyl-tRNA synthetase family, a group of enzymes that ensure accurate translation of the genetic code. The enzyme catalyses the attachment of serine to its cognate transfer RNA molecules in a two-step reaction requiring ATP. First, serine and ATP form an activated aminoacyl-adenylate intermediate. Second, the enzyme transfers serine from this intermediate onto the appropriate tRNA molecule. This aminoacylation reaction must achieve high fidelity to prevent mistranslation errors that could compromise mitochondrial protein quality. The enzyme specifically recognises mitochondrial tRNA-Ser molecules, distinguishing them from cytoplasmic serine tRNAs. By maintaining an accurate supply of seryl-tRNA, SARS2 supports the continuous production of essential respiratory chain components within the mitochondrial matrix.
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Chromosome location
SARS2 is located on chromosome 19 at position 19q13.2. This chromosomal region contains numerous genes, and the precise genomic context contributes to the gene's regulation and expression patterns across different tissues.
Protein structure
The SARS2 protein comprises 518 amino acids. The C-terminal region includes a disordered segment spanning amino acids 498 to 518, which may provide flexibility for protein interactions or regulatory modifications. The catalytic core contains the characteristic features of class II aminoacyl-tRNA synthetases, enabling both ATP-dependent amino acid activation and tRNA recognition.
Key variants
Pathogenic variants in SARS2 typically reduce or abolish the enzyme's ability to charge mitochondrial tRNA molecules with serine. Missense variants affecting the catalytic domain or tRNA-binding regions are commonly reported. The severity of clinical manifestations often correlates with the degree of residual enzyme activity, with complete loss-of-function variants generally associated with more severe early-onset presentations.
No pathogenic or likely-pathogenic ClinVar variants recorded yet for this gene.
Associated conditions
SARS2-related disorders manifest as mitochondrial diseases with variable presentations affecting multiple organ systems. Common features include developmental delay, intellectual disability, metabolic disturbances, and progressive neurological decline. Some individuals develop hyperuricaemia and gout due to disturbed purine metabolism. Renal involvement can present as tubulopathy or unexplained kidney dysfunction in young people. Pulmonary arterial hypertension has been documented in certain cases. The clinical spectrum reflects the critical dependence of high-energy-demand tissues on efficient mitochondrial protein synthesis.
No disease links recorded for this gene in our reference set.
UK clinical status
SARS2 appears on multiple NHS Genomic Medicine Service gene panels with green (high-evidence) classification. It is included in panels for mitochondrial disorders, intellectual disability, likely inborn errors of metabolism, undiagnosed metabolic disorders, renal tubulopathies, unexplained kidney failure in young people, and pulmonary arterial hypertension. This broad panel representation reflects the diverse clinical presentations associated with SARS2 variants and supports genetic testing in individuals presenting with compatible multisystem features.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Frequently asked questions
What does the SARS2 gene do?
The SARS2 gene encodes an enzyme that attaches the amino acid serine to specific transfer RNA molecules within mitochondria. This process is essential for mitochondria to produce their own proteins, which are critical components of the cellular energy-production machinery.
How are SARS2 variants inherited?
SARS2-related conditions typically follow an autosomal recessive inheritance pattern, meaning an individual must inherit a pathogenic variant from both parents to develop the condition. Carriers with one variant copy generally do not show symptoms.
Which organs are most affected by SARS2 variants?
Organs with high energy requirements are most vulnerable, including the brain, kidneys, heart, and skeletal muscles. The specific pattern of organ involvement varies among affected individuals, but neurological and metabolic features are commonly observed.