Secondary infertility as early symptom in a man with multiple endocrine neoplasia-type 1

Multiple endocrine neoplasia-type 1 (MEN1) is an autosomal dominant familial cancer syndrome characterized by parathyroid hyperplasia, pancreatic endocrine tumours and pituitary adenomas. Here, we report a patient with a history of insulinoma who developed secondary infertility as a further symptom of the disease. When he was first examined at the age of 36 years, he complained of weakness, reduced libido and impotence. Laboratory evaluation revealed non-obstructive azoospermia and hyperprolactinaemia. In contrast to sexual activity and serum prolactin, semen quality did not significantly respond to bromocriptine therapy. During follow-up, a growing pituitary adenoma caused acromegaly with elevated serum concentrations of growth hormone, insulin-like growth factor 1 (IGF-1), and prolactin. After microsurgery of the tumour at the age of 44 years, sperm concentration persistently increased up to 5.6 x 10(6)/ml. In accordance with the clinical diagnosis of MEN1, DNA sequencing revealed a mutation in exon 2 of the menin gene which results in a truncated, inactive protein product. In conclusion, MEN1 with pituitary lesions may cause severe hypogonadism and infertility. Both hyperprolactinaemia and overproduction of growth hormone and IGF-1 seem to be involved in testicular dysfunction in the present case. The possible role of menin in the testis, however, remains to be elucidated.