IGSF1 and fragile X syndrome: In addition, the testicular volume is of interest to assess macroorchidism, such as in Fragile X syndrome, FSH secreting pituitary macroadenomas, immunoglobulin superfamily member 1 (IGSF1) deficiency syndrome [2], long-standing hypothyroidism, adrenal rest cell tumors in congenital adrenal hyperplasia, lymphomas and so on.