Sarcosinemia

Sarcosinemia (also known as hypersarcosinemia or sarcosine dehydrogenase deficiency) is a rare autosomal recessive metabolic condition characterized by elevated levels of sarcosine (N-methylglycine) in the blood and increased excretion of sarcosine in the urine (sarcosinuria). It is caused by a deficiency of the enzyme sarcosine dehydrogenase (also called sarcosine oxidase), which is involved in the conversion of sarcosine to glycine in the folate metabolism pathway. The condition is associated with variants in the SARDH gene located on chromosome 9q34. Sarcosinemia is now widely considered a benign biochemical phenotype rather than a clinically significant disease. It was initially reported in association with neurological features such as intellectual disability, growth delay, and cardiomyopathy in early case reports. However, subsequent population-based newborn screening studies identified many individuals with elevated sarcosine levels who were completely asymptomatic, suggesting that the neurological findings in early cases were likely coincidental rather than causally related to the enzyme deficiency. The condition primarily affects amino acid metabolism without consistent clinical consequences. Because sarcosinemia is generally regarded as a benign metabolic variant, no specific treatment is typically required. Dietary restriction of sarcosine or its precursors has not been shown to be necessary or beneficial. Genetic counseling may be offered to affected families. Monitoring may be considered in rare cases where clinical symptoms are present, though the causal relationship between elevated sarcosine and any symptoms remains unestablished. The condition is most often detected incidentally through newborn screening programs or metabolic investigations performed for other reasons.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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