Treatment of urea cycle disorders includes a low-protein diet, adequate calorie intake, alternative-pathway treatment for hyperammonaemic crises, and dialysis if needed. Alternative-pathway treatment consists of giving phenylacetate and benzoate so that waste nitrogen is excreted as phenylacetylglutamine and N-benzoylglycine rather than producing ammonia. It was first suggested by Brusilow and colleagues in 1979 and now a multicentre US study extending over 25 years has been reported by researchers including Dr Brusilow …