The biochemical and clinical efficacy of dietary erucic acid (C22:1) therapy for X-l inked adrenoleukodystrophy (ALD) was investigated at the Departments of Pediatrics, Human Genetics, Neurology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, and the Department of Neurology, University of California, Davis, Sacramento, CA. Twelve patients, aged six to 12 years, were treated with a diet enriched with erucic acid and oleic acid for 2-19 months. The mean plasma C26:0 concentration decreased to normal by four weeks, and the C26:0 composition of plasma sphingomyelin and phosphatidylcholine became normal by four months. Two mildly affected patients remained clinically stable whereas six with moderate to advanced disease deteriorated. The diet may prevent further demyelinization in some mildly affected boys with X-linked adrenoleukodystrophy. [1]

COMMENT. X-linked adrenoleukodystrophy is an inborn error of metabolism characterized by adrenal insufficiency and progressive demyelinization. ALD is usually fatal within several years after onset of neurologic abnormalities. A clinically milder form of ALD, adrenomyeloneuropathy, has a later age of onset and slower progression. The authors consider that the dietary erucic acid therapy may be more useful in patients with this milder form of ALD and in presymptomatic boys who express the biochemical defect of ALD.

The possibility of adrenomyeloneuropathy should be considered in any boy with Addison's disease [2]. These authors measured the plasma concentrations of very long chain saturated fatty acids in eight patients with adrenal insufficiency; five had elevated plasma hexacosanoic acid confirming the presence of adrenomyeloneuropathy. MRI showed brain involvement in all five patients. It was concluded that adrenomyeloneuropathy may present as Addison's disease in childhood.

In a further recent study from the Departments of Pediatric Endocrinology and Radiology, Hopital Saint Vincent de Paul, Paris, France, the MRI detected white matter lesions in two of seven patients with biochemically proven ALD but without neurologic manifestations. The ages at the time of MRI diagnosis were 14 and 21 years [3]. Six of the seven neurological ly asymptomatic ALD patients in this study had adrenal insufficiency.