Organic acidurias and amino acidurias in the aetiology of long-term mental handicap.

In order to evaluate the contribution of patients with organic aciduria and amino acidopathies to populations with severe long-term mental handicap, urine from a total of 1,778 such patients from four hospitals has been examined for organic acids and amino acids. The patients have been classified into eight groups according to the nature of their handicap. It is concluded that, apart from phenylketonuria originating from before dietary treatment was available, known inherited metabolic diseases do not contribute significantly to the incidence of mental handicap in the population studied.