Addison disease and cerebral sclerosis in an apparently heterozygous girl: evidence for inactivation of the adrenoleukodystrophy locus.

Cerebral sclerosis and Addison disease were observed at age 14 years in a previously healthy sister of an affected boy. Clinical findings and family history established the diagnosis of X-linked adrenoleukodystrophy, which is normallly confined to males. The affected female has a normal karyotype; both X chromosomes are morphologically inconspicuous. Thus, this patient may be the first documented example of clinically manifest adrenoleukodystrophy in a heterozygote, which supports our previous conclusion that this X-linked locus is subject to inactivation.