A 4 1/2-year-old girl with a so far unremarkable medical history became comatose 
during a simple infection. She showed severe metabolic acidosis without 
elevation of lactate. In blood the branched-chain amino acids were increased. In 
urine ketone-bodies, increased 3-OH-isovaleric and 3-OH propionic acid excretion 
were detected, while methylmalonate was not found. The profile of acylcarnitines 
revealed increased propionylcarnitine. Despite restriction of protein supply, 
high-caloric nutrition, correction of acidosis, and supplementation of biotin 
and carnitine, the girl died 2 days after admission due to arrhythmia of the 
heart. In skin fibroblasts the activity of propionyl-coenzyme A carboxylase 
(PCC) was markedly decreased. Mutation analysis confirmed the diagnosis of 
propionic acidemia (PA) with compound heterozygosity for 2 new missense 
mutations L417W/Q293E in the PCCA gene, with the mother carrying the Q293E and 
the father the L417W mutation. Late-onset PA should be included in the 
differential diagnosis of unclear coma. Determination of the acylcarnitines 
using tandem mass spectrometry as well as organic acids in urine is recommended.