There are numerous other syndromic conditions associated with hypogonadotropic hypogonadism (Table 6), including IGSF1 deficiency, which results in a syndrome of X‐linked central hypothyroidism with delayed puberty and macro‐orchidism in male patients, reflecting their relative FSH excess.72 The gene discussed is BRD2; the disease is hyperinsulinemic hypoglycemia, familial, 4.