In humans, heterozygous SOX2 loss-of-function mutations are associated with anophthalmia (Fantes et al. 2003) and hypogonadotrophic hypogonadism (reduced gonadal function of hypothalamic origin) (Kelberman et al. 2006), while both SOX3 deletions and duplications are linked to mild hypopituitarism (Laumonnier et al. 2002). The gene discussed is SOX2; the disease is hypogonadotropic hypogonadism.