Propionic acidaemia. First case in the Finnish population.

Propionic acidaemia is a defect of propionyl-CoA-carboxylase activity characterized by urinary excretion of propionic acid, its metabolites and hyperglycinaemia. The clinical picture of this autosomally, recessively inherited disorder, which has been reported in the literature in 63 patients varies from overwhelming metabolic crisis in the neonate to an almost asymptomatic disease responding to protein restriction and biotin supplementation. The first Finnish patient with propionic acidaemia had a severe type of disease with neonatal onset simulating nonketotic hyperglycinaemia. In spite of protein restriction and biotin supplementation this infant developed progressive psychomotor retardation and died of intercurrent infection at the age of 8.5 months. The definite, correct diagnosis was not reached until a severe infection occurred, during which the pathognomonic organic aciduria manifested. This delay in the diagnosis illustrates the importance of performing the analysis of urinary excretion of organic acids during stress situations, such as infections, since the metabolic block may be undetectable under normal conditions.