Pituitary homeobox 3 is a protein that in humans is encoded by the PITX3 gene.[4][5]
This gene encodes a member of the RIEG/PITX homeobox family, which is in the bicoid class of homeodomain proteins. Members of this family act as transcription factors. This protein is involved in lens formation during eye development,[5] and the specification and terminal differentiation of mesencephalic dopamine neurons in the substantia nigra compacta that are lost in Parkinson's disease.[6]
Mutations of this gene have been associated with anterior segment mesenchymal dysgenesis (ASMD) and congenital cataracts.[5]