Mutations within the chromodomain helicase DNA-binding protein 7 (CHD7) have been identified in patients with CHARGE association, a syndrome in which hypogonadotropic hypogonadism and hyposmia are associated with choanal atresia, coloboma of the iris (Figure 3), cardiovascular malformations, retardation of mental and somatic development, and ear anomalies [13, 39]. Here, CHD7 is linked to hypogonadotropic hypogonadism.