Macrotestes associated with hyperprolactinemia

IGSF1 deficiency syndrome: A newly uncovered endocrinopathy

A recently uncovered X-linked syndrome, caused by loss-of-function of IGSF1, is characterized by congenital central hypothyroidism and macroorchidism, variable prolactin deficiency, occasional growth hormone deficiency, delayed pubertal testosterone secretion and obesity. We propose to call this endocrinopathy “IGSF1 deficiency syndrome.” Based on an estimated incidence of isolated congenital central hypothyroidism of 1:65,000, we predict that the incidence of IGSF1 deficiency related hypothyroidism is approximately 1:100,000. IGSF1 encodes a plasma membrane immunoglobulin superfamily glycoprotein that is highly expressed in pituitary and testis, but is of unknown function. The variable profile of pituitary dysfunction suggests that IGSF1 may play a role in pituitary paracrine regulation. The clinical significance of the syndrome, particularly the clinical consequences of untreated hypothyroidism, justifies screening family members of patients with IGSF1 mutations for carriership and to study potential carriers of IGSF1 mutations, including patients with idiopathic central hypothyroidism, combined GH and TSH deficiency, macroorchidism or delayed puberty.

Macroorquidismo: a propósito de un caso

Macroorchidism is a rare condition in children and is usually associated with fragile X syndrome. Other possible etiologies of macroorchidism are long-standing primary hypothyroidism, adrenal remnants in congenital adrenal hyperplasia, follicle stimulating hormone (FSH)-secreting pituitary macroadenomas, local tumors, lymphomas, and aromatase deficiency. Bilateral macroorchidism can be a normal variant in adult men. We report the case of an 11.5-year-old boy who was referred to our hospital for evaluation of marked bilateral testicular enlargement in the previous few months. Physical examination revealed a testicular volume larger than 30 ml. Complementary investigations allowed us to rule out all hitherto reported etiologies of bilateral macroorchidism and therefore a diagnosis of idiopathic macroorchidism was established. The increased number of Sertoli cells found on biopsy, without elevated plasma FSH levels, prompted us to speculate about a hypothetical FSH receptor hyperfunction as a possible cause of the exaggerated testicular enlargement in this patient.