OTX2 is also involved in pituitary gland development through the control of HESX1 and POU1F1 transcription factors [57,58], and in adult functioning, as observed in patients where deletion or mutations of OTX2 are associated with pathologies with variable expression, ranging from anophthalmia, ear abnormalities, and hypopituitarism [59] to pituitary hypoplasia and defects in pituitary hormone production [58,60,61,62,63]. This evidence concerns the gene OTX2 and Abnormality of the ear.