AARS1 / AARS2

AARS2 belongs to a group of "mitochondrial" tRNA-synthetase genes whose faults cause hard-to-diagnose conditions, often with childhood brain disease and seizures. Drawing on a large Europe-wide rare-disease cohort, this study built a systematic way to compare a patient's features with previously reported cases to judge whether a genetic variant is truly the cause. Approaches like this make it easier and faster to confirm a diagnosis of AARS2-related and similar disorders, which can otherwise take years.

In diseases like AARS2-related leukoencephalopathy, a gene needed to build proteins inside mitochondria doesn't work properly. Earlier lab work hinted that supplying the specific amino acid each faulty enzyme handles might help. This pilot clinical trial tested that idea in six adults, including patients with AARS2, by giving the corresponding amino-acid supplement and tracking safety and response. Early-stage studies like this are the first careful step toward a possible treatment for a group of conditions that currently have none.

AARS2-related disease belongs to a family of conditions caused by faulty mitochondrial "aminoacyl-tRNA synthetase" enzymes, and doctors need simple blood tests to detect and monitor them. This study measured FGF21, a hormone that tends to rise when mitochondria are stressed, in patients whose genetic testing revealed changes in AARS2 and related genes, comparing them with healthy volunteers. Finding that FGF21 was elevated suggests a straightforward blood marker could support diagnosis and follow-up for this group of rare mitochondrial diseases, including AARS2.

AARS1 gene changes can cause disease in two different inheritance patterns, recessive multi-system disorders and a later-onset dominant nerve disease, and it is unclear how the same gene produces both. Using a "humanized yeast" model, researchers tested the recessive disease-causing variants side by side and found they reduce the enzyme's function to varying degrees. The study validates yeast as a reliable tool for judging whether an AARS1 variant is harmful, useful for interpreting uncertain genetic results in patients.

AARS2-related disease can appear in infancy with developmental delay and progressive neurological symptoms, and reaching a diagnosis often hinges on genetic testing. This case describes a 17-month-old child with global developmental delay and low muscle tone whose AARS2 gene change was initially labeled "uncertain," then later recognized as the cause once similar cases were published. It is a reminder that genetic results sometimes need re-interpreting over time, and that comparing a child's features with newly reported cases can secure a diagnosis.

AARS2-related leukoencephalopathy and the more familiar CSF1R-related leukoencephalopathy can look almost identical, clinically, on MRI, and even under the microscope, yet they arise from faults in different genes and are easily confused. Researchers at a Chinese leukoencephalopathy clinic compared 23 CSF1R and 6 AARS2 patients to find the features that reliably tell them apart. Practical guidance like this helps doctors reach the correct genetic diagnosis sooner, which matters because management and family counseling differ between the two conditions.

Diseases caused by faults in aminoacyl-tRNA synthetases (the family that includes AARS1 and AARS2) currently have no disease-specific treatments. This review surveys the emerging therapeutic ideas being explored: supplying the amino acid the enzyme normally handles, delivering healthy tRNA molecules to relieve bottlenecks in protein-making, and using small molecules or nucleic-acid-based drugs. It offers patients and families a clear picture of the experimental strategies that could one day lead to treatments for AARS1/AARS2-related disease.

GeneReviews is a trusted, regularly updated reference written by experts. This entry describes the two faces of AARS2-related disorder: a severe infantile-onset heart-muscle disease (cardiomyopathy) on one hand, and, on the other, the adult neurodegeneration-with-leukoencephalopathy form marked by movement problems, cognitive decline, ovarian failure in women, and psychiatric symptoms. It explains how the diagnosis is confirmed genetically and how the condition is managed and inherited, a practical, authoritative orientation for families navigating this rare AARS2 disease.