Development of the gonadotrophic resistant ovary syndrome in myasthenia gravis: suggestion of similar autoimmune mechanisms.

A woman with myasthenia gravis who developed hypergonadotrophic amenorrhoea was studied. This patient fulfilled all accepted criteria for the diagnosis of the gonadotrophin resistant ovary syndrome: high levels of serum LH and FSH by radioimmunoassay and urinary gonadotrophin excretion by bioassay, low serum oestradiol, lack of response to exogenous gonadotrophin and ovaries with multiple non-stimulated primordial follicles. The serum of this patient contained a substance which behaving like a gamma globulin, inhibited FSH specific binding to receptors in an in vitro system. This inhibitor was looked for in further patients with hypergonadotrophic amenorrhoea, other immunological diseases or myasthenia gravis with normal menses. Ovarian biopsy was not available in these patients. In all except one who also had the association of myasthenia gravis and hypergonadotrophic amenorrhoea, the inhibitor was not detected. It is suggested that development of antibodies directed against gonadotrophin receptors or a receptor related membrane domain may play a role in the mechanism of failure of gonadotrophin stimulation in some patients with the gonadotrophin resistant ovary syndrome.