BRD2 and cartilage-hair hypoplasia: In males, CHH affects between 1 in 4400 and 15 000 live births.2 The condition may be secondary to a lack of gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus or abnormal gonadotropin (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) secretion from the anterior pituitary gland, leading to reduced endogenous sex steroid production from the gonads.