Abstract

Seven subjects with raised plasma histidine and low skin histidase levels (histidinaemia) are described: 4 were severely retarded, 2 showing in addition features of an early infantile psychosis (autism); 3 were of normal intelligence. There were no biochemical differences between the two groups.

In view of these findings and a study of patients reported in the literature, attention is drawn to the difficulty in making a decision about treatment of a neonate detected by screening and shown to have the biochemical features of histidinaemia. The natural history of the condition is further examined, particularly the question of deterioration at time of seizures or infection.