Professional
Technical
IVT
leucine:isoleucine ratio
A calculated ratio used to distinguish maple syrup urine disease from other aminoacidopathies.
Full Definition
The leucine to isoleucine ratio is a diagnostic marker for maple syrup urine disease (MSUD). In MSUD, leucine levels rise disproportionately compared to isoleucine due to preferential metabolism of isoleucine by residual enzyme activity. This ratio helps differentiate MSUD from other causes of elevated branched-chain amino acids and guides the urgency of follow-up testing.
Usage
Usage note: Use full amino acid names when first mentioned, then abbreviations are acceptable.
In Context
- "The leucine:isoleucine ratio was 4.8, strongly suggestive of MSUD." — Biochemical genetics report
- "A normal leucine:isoleucine ratio helps exclude MSUD in cases with mildly elevated leucine." — Screening protocol
Also known as
leu:ile ratio
Don't confuse with
valine levels
alloisoleucine