Signs of testicular insufficiency in adrenomyeloneuropathy and neurologically asymptomatic X-linked adrenoleukodystrophy: a retrospective study.
X-linked adrenoleukodystrophy (X-ALD) is characterized by central nervous system demyelination, and impaired steroidogenesis in the adrenal cortex and testis. Most patients develop adrenocortical insufficiency. We studied retrospectively the frequency and severity of testicular dysfunction in 26 men with X-ALD. Twenty-one had adrenomyeloneuropathy and five patients were neurologically asymptomatic. In addition to obtaining a routine history and physical examination, we studied plasma levels of testosterone, sex hormone binding globulin, the free androgen index, and the plasma concentrations of dehydroepiandrosterone-sulphate, LH and FSH. In a subset of patients, the testosterone response to hCG and the LH and FSH responses to GnRH were also determined. Clinical signs of gonadal dysfunction were manifested by diminished libido (46%), largely overlapping with erectile dysfunction (58%), and failure of the testes to descend (15%). Physical examination revealed diminished body sexual hair (50%), gynaecomastia (35%), and small testes (12%). Laboratory studies showed low plasma total testosterone levels in 12%, and an insufficient increase after stimulation with hCG in 88% (15 of 17 patients tested). Plasma LH concentration was increased in 16%, and the plasma FSH level was elevated in 32%. The response of LH concentrations to GnRH stimulation was abnormally high in 47% (nine of 19 patients studied), and the response of FSH levels was too low in 16% (three of 19 patients tested). In conclusion, in a retrospective study of 26 men' with X-ALD, in 20 some signs of clinical hypogonadism were found. Plasma testosterone values were generally in the normal range, but upon testing of the hypothalamo-pituitary-testis axis some abnormalities became apparent.