Maple syrup urine disease (MSUD) is a rare inborn error of metabolism, caused by a deficiency in
activity of the branched chain alpha-keto acid dehydrogenase impairing the degradation of the branchedchain
amino acids (leucine, isoleucine and valine). Classic MSUD usually manifests in the neonatal period
with poor feeding, vomiting, lethargy, muscular hypertonicity, seizure, coma and death. Thirteen cases of
classic MSUD were diagnosed from 1997-2007 at the Queen Sirikit National Institute of Child Health. All
cases presented in the neonatal period. The onset of symptoms ranged from 3 to 20 days (median 8 days). The
time taken to make the diagnosis ranged from 18 to 356 days (median 55 days). The diagnosis was accomplished
by clinical diagnosis and confirmed by detecting abnormal levels of amino acids in the blood and
organic acids in the urine. Clinical manifestations were non-specific such as poor suck, weak cry, drowsiness
and seizures. Majority of cases were initially diagnosed as sepsis and/or meningitis. All patients had neurological
sequelae and psychomotor retardation. This results show the need for increase awareness of metabolic
disorder such as MSUD and the requirement for early detection and treatment to ensure a better outcome.

Keywords: Maple syrup urine disease, Branched-chain amino acids