Transient trimethylaminuria in childhood.

Trimethylaminuria, also called fish-odour syndrome, is an inherited disorder caused by deficient N-oxidation and increased excretion of trimethylamine. This study reports on two unrelated and otherwise healthy children with transient trimethylaminuria, a hitherto unknown abnormality, without N-oxidation deficiency. This demonstrates that a diagnosis of fish-odour syndrome should include the analysis of urinary excretion not only of trimethylamine but also of trimethylamine-N-oxide. Since transient trimethylaminuria may be a common condition and no cause for it can presently be recognized, such patients will require careful follow-up.