4,5-dimethyl-3-hydroxy-2[5H]-furanone (sotolone) - The odour of maple syrup urine disease

Maple syrup urine disease is an autosomal recessive inherited disorder of b ranched-chain amino acid metabolism due to deficiency of the branched-chain alpha-keto acid dehydrogenase complex. The disease was originally named af ter the characteristic sweet aroma, reminiscent of maple syrup, present in the body fluids of affected patients. Until now, the substance responsible for the odour has not been positively identified. Using enantioselective mu ltidimensional gas chromatography-mass spectrometry (enantio-MDGC-MS), we c ould demonstrate that 4,5-dimethyl-3-hydroxy-2[5H]-furanone (sotolone), a w ell-known flavour impact compound present in fenugreek and lovage, was pres ent in urine from seven patients with maple syrup urine disease. Urine samp les from healthy control persons lacked sotolone. We have shown that sotolo ne is responsible for the characteristic odour of maple syrup urine disease and, since maple syrup also contains sotolone, the naming of this disease appears to be correct.