Riboflavin responsive multiple acyl-CoA dehydrogenation deficiency. Assessment of 3 years of riboflavin treatment.

A boy with riboflavin-responsive beta-oxidation deficiency (multiple acyl-CoA dehydrogenation deficiency) was assessed clinically and biochemically after 3 years of continuous riboflavin medication. He was diagnosed at the age of three years after an attack of a Reye's syndrome-like disease. During the 3 years of assessment he has experienced no serious disease; although short episodes of fatigue and loss of appetite have been noted. His mental and physical development has been normal. Biochemically the abnormal excretion of organic acid metabolites, characteristic of the acyl-CoA dehydrogenation deficiency, has been continuously present. Quantitatively there has been a trend to a more simple picture with ethylmalonic acid as the predominant metabolite. However, because of the large within-day variation in the excretion of all the metabolites, changes following diet and riboflavin trials must be interpreted with caution in these patients.