3-Hydroxy-3-methylglutaryl coenzyme A lyase deficiency. Follow-up of first described case.

We report the progress of a child with a defect in leucine metabolism due to a deficiency of 3-hydroxy-3-methylglutaryl Coenzyme A lyase activity. This child was reported briefly in 1976 when the abnormality was first suspected at which time he was 7 months old. He is now aged 4 years 7 months and appears to be well and developing satisfactorily. His diet has been difficult to control and the biochemical defect is extremely sensitive to small amounts of leucine in the diet.