[Adrenoleukodystrophy: significance for genetic counseling of the determination of very long-chain fatty acids and of molecular biology].

Juvenile adrenoleukodystrophy (ADL) is a peroxisomal, X-linked, consistently fatal condition for which no treatment is currently available. Detection of heterozygote females and antenatal diagnosis by determination of very long chain fatty acid levels are therefore mandatory. We report the case of a family with two affected first cousins but six unaffected maternal uncles. Plasma levels confirmed the usual X-linked pattern with transmission by the grandmother and ruled out the hypothesis of delayed adrenomyeloleukodystrophy in the grandfather with heterozygosis of all the daughters. Although all six sons are unaffected, two certainly heterozygote females have normal plasma very long chain fatty acid levels. Heterozygosis in these women was confirmed by family restriction fragment length polymorphism studies (TAQ1) using the St 14 probe whose reliability for the diagnosis of heterozygotes with normal plasma very long chain fatty acid levels has previously been documented.