Testicular dysfunction in adrenomyeloneuropathy

Department of Clinical Biochemistry, University of Bonn, Germany.

Adrenomyeloneuropathy (AMN) is a disorder due to a disturbance in the peroxisomal beta-oxidation of saturated very long chain fatty acids. It is characterized by symptoms of the nervous as well as the endocrine systems, especially the adrenal cortex and the gonads. We investigated the testicular function in 49 male AMN patients aged 36.2 +/- 1.5 years (range, 18.5-59 years). Twenty-four of these patients were suffering from adrenocortical insufficiency. Twenty-five AMN patients showed neurological symptoms without 'Addison's disease'. To register the frequency and the degree of gonadal impairment, LH and FSH, testosterone, free testosterone and inhibin-B were determined. Gonadotropin concentrations were significantly higher in AMN patients than in healthy controls (LH, 8.0 +/- 1.2 vs 2.77 +/- 0.11 IU/l; FSH, 10.1 +/- 1.6 vs 4.0 +/- 0.17 IU/l; P < 0.001). Serum LH was elevated in 31 patients (63.3%); 28 patients (57.1%) showed elevated serum FSH indicating deficient spermatogenesis. Mean testosterone did not differ significantly between patients and healthy controls, but mean free testosterone was significantly lower in patients than in controls (16.3 +/- 1.0 vs 28.5 +/- 1.68 pg/ml, P < 0.002). Inhibin-B concentrations did not differ between AMN patients and healthy men. The testosterone/LH ratio reflecting an impairment of the Leydig cells was significantly lower in AMN patients than in controls (P < 0.01). An impairment of the Leydig cells and/or of the Sertoli cells was evident in 81.6% of AMN patients. Twenty-one of thirty-nine patients (53.8%) admitted erectile dysfunction. These data indicate that endocrine dysfunction in AMN is not only confined to adrenocortical functions, but testicular dysfunctions also frequently occur, thus permitting the term 'adreno-testiculo-myelo-neuropathy'.