Adrenal steroid dysregulation in dystrophia myotonica.

OBJECTIVE

To evaluate circulating adrenal steroid hormones, cortisol diurnal rhythm and the negative feedback function of the cortisol axis in patients with dystrophia myotonica (DyM), a disease where metabolic disturbances, peripheral insulin insensitivity and cognitive dysfunction are common features.

DESIGN

Morning serum levels of dehydroepiandrosterone sulphate, androstenedione, 17 alpha-hydroxy progesterone and cortisol; morning serum levels of testosterone and insulin; diurnal rhythm of saliva cortisol; and an overnight dexamethasone suppression test, together with a cognitive screening test in men with DyM and in controls.

SETTING

Outpatient clinic in co-operation with Umeå University Hospital.

SUBJECTS

Fifteen men with DyM and 13 age-matched controls.

MAIN OUTCOME MEASURES

Adrenal steroid hormone levels, diurnal rhythm of saliva cortisol, dexamethasone suppression test and Mini Mental State Examination scores.

RESULTS

Morning serum levels of dehydroepiandrosterone sulphate, androstenedione and 17 alpha-hydroxy progesterone were significantly decreased in DyM after inclusion of age and body mass index in multiple regression analyses (48, 26 and 32% decreases, respectively). An abnormal diurnal rhythm of saliva cortisol was present in all patients, mean saliva cortisol levels being significantly increased (33%) in DyM patients. Dexamethasone suppressibility did not differ between groups. DyM patients scored significantly lower on the Mini Mental State Examination (P < 0.001).

CONCLUSIONS

These results indicate an abnormal adrenal steroid hormone secretion in DyM, which may contribute to peripheral insulin sensitivity as well as cognitive impairment in these patients.