Management of SARS1-related disorders is primarily supportive and requires a multidisciplinary approach. Regular surveillance is essential to monitor for and proactively manage the multisystemic complications associated with the condition.
Surveillance
● Neurological: Regular assessment by a pediatric neurologist is critical for monitoring developmental progress, tone, and movement disorders (ataxia, spasticity). Electroencephalogram (EEG) monitoring should be performed to characterize and manage seizure activity. Early and aggressive intervention with anti-epileptic drugs (AEDs) is indicated for seizure control.
● Developmental: Patients should undergo comprehensive developmental assessments to guide therapies. Enrolment in early intervention programs, including physical, occupational, and speech therapy, is fundamental to maximizing developmental potential.
● Cardiac: Given the reported risk of cardiomyopathy in individuals with biallelic mutations, a baseline echocardiogram and electrocardiogram (EKG) at the time of diagnosis are recommended. Ongoing surveillance by a cardiologist should be tailored to the individual's clinical status.
● Audiology: A formal hearing evaluation should be conducted at diagnosis and periodically thereafter to screen for sensorineural hearing loss.
● Growth and Nutrition: Growth parameters, including head circumference, weight, and height, should be monitored closely. A formal feeding evaluation is warranted for individuals with dysphagia or failure to thrive, with a low threshold for considering gastrostomy tube placement to ensure adequate caloric intake.
Therapeutic Approaches
● Supportive Care: The cornerstone of management includes standard-of-care interventions for seizures, spasticity, and developmental support. A critical aspect of care is the aggressive management of fever and intercurrent illnesses to prevent episodes of acute clinical decompensation, which have been reported in severe cases.
● Targeted Therapy - L-serine Supplementation: An emerging, personalized treatment strategy involves supplementation with high doses of L-serine. The biochemical rationale for this approach is based on fundamental principles of enzyme kinetics. Since SARS1 is responsible for charging tRNA with L-serine, a deficiency in its function creates a bottleneck in protein synthesis. Supplementing with high doses of L-serine aims to increase the intracellular concentration of the substrate, which can enhance the residual activity of the mutant enzyme and boost the overall rate of tRNA serylation.
This approach represents a potential shift from purely supportive care to a disease-modifying therapy. Studies involving cohorts of patients with various cytosolic aminoacyl-tRNA synthetase (ARS) deficiencies, including SARS1, have demonstrated beneficial effects from supplementation with the corresponding cognate amino acid. Reported improvements have included better growth (reducing the need for tube feeding), increased head circumference, developmental gains, and improved tolerance of infections. One study reported the use of L-serine at dosages of 85.7–97.5 mg/kg/day. This therapy should be considered experimental and must be undertaken under the close supervision of a metabolic specialist. The potential of such a targeted therapy underscores the importance of a rapid and accurate molecular diagnosis to facilitate early intervention.
SARS1