SOX2 and microphthalmia: For instance, the association of congenital multiple pituitary hormone deficiency with septo-optic dysplasia (midline neural defects and optic nerve hypoplasia) has been observed in patients with mutations in HESX1, SOX2 and SOX3. Midline defects, coloboma and polydactyly are also present in HESX1 patients, anophthalmia or microphthalmia and esophageal atresia in SOX2 cases, and X-linked mental retardation in SOX3 mutations.