Investigations

The diagnosis is often suspected because of the peculiar odour of maple syrup found in the urine and sweat.

• analysis of amino acid plasma concentrations reveals:
  • raised levels of leucine, isoleucine, valine and alloisoleucine - latter is an amino acid that is not usually found in the bloodstream.
• leucine level in the plasma is usually higher than the other three amino acids.
  
  
• urinanalysis - high levels of leucine, isoleucine and valine - the ketoacids of these amino acids are also raised.