X-LINKED ADRENOLEUKODYSTROPHY IN PATIENTS WITH IDIOPATHIC ADDISON-DISEASE

The two main causes of primary adrenal disease are tuberculosis and au to-immune adrenal destruction. The latter is responsible for about 70% of the cases of primary adrenal insufficiency (Addison disease). Comm only referred to as a rare cause of adrenal failure is X-linked adreno leukodystrophy (ALD), a demyelinating peroxisomal disorder affecting 1 : 20000 Caucasian males. Albeit primary adrenal insufficiency is a rar e entity per se, we decided to study patients with idiopathic Addison disease and establish the frequency of ALD as a cause of adrenal insuf ficiency. The biochemical defect of ALD was found in 5 out of 24 patie nts. The small number of cases in our series led us to include in our analysis the published results of two other groups of investigators. T his analysis indicates that the proportion of cases in which Addison d isease is attributable to ALD is age dependent. It is highest when the adrenal insufficiency manifests before 15 years. This study clearly d emonstrates that the proportion of ALD in patients presenting primary adrenal insufficiency has been underestimated.