Gonadal Dysfunction in Patients with Myotonic Dystrophy

 

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Summary

In order to investigate the frequency and type of gonadal dysfunction in myotonic dystrophy (MD), we studied 29 patients (13 women and 16 men). In addition to assesment of the basal reproductive hormone status, pituitary sensitivity to GnRH was evaluated with GnRH (Relisorm^®)-test in 12 (5 women and 7 men) patients with MD, and 10 (5 women and 5 men) control subjects. In two female patients, who had secondary amenorrhea, estradiol provocation test has been performed.

Testicular atrophy was found in 13 male patients. The elevated basal FSH levels were observed in 75%, and LH in 43.7% male patients, while testosterone levels were decreased in 37.5% of them.

Two female patients had normogonadotropic normoprolactinemic secondary amenorrhea, and four presented oligomenorrhea. Increased basal LH and FSH concentrations, together with the basal estradiol level at the lower limit of normal values, were observed only in one female patient with oligomenorrhea. Hyperprolactinemia has been established in 23.0% female patients.

After administration of GnRH, an increased pituitary sensitivity of LH and FSH secretion has been observed in male patients (male patients versus controls: p < 0.01). The most exaggerated FSH response has been noticed in male patients with increased basal FSH. Significant positive correlation was observed between basal FSH level and maximal FSH increment during GnRH test (r = +0.714; p < 0.05).

An increased response of FSH to GnRH has been also observed in female patients with MD, but when compared to controls, that difference was not statistically significant. Significant positive correlation was established between basal FSH levels and maximal FSH increase after GnRH in female patients (r = +0.927; p < 0.05). The response of LH to GnRH was lower in MD females in comparison to controls, but the difference was statistically insignificant.

In two female patients with normogonadotropic normoprolactinemic secondary amenorrhea positive feed-back effect of estradiol on LH secretion was observed, but only in one out of two female patients positive feed-back effect of estradiol on FSH was observed.