PITX2 and Axenfeld-Rieger syndrome: Two genes encoding Paired-like homeodomain 2 (Pitx2), a homeobox transcription factor whose human orthologue is implicated in Axenfeld-Rieger syndrome type 1 (OMIM #180500), and Catenin beta 2 (Ctnnb2), an adherens junction protein that also functions as a transducer of the canonical Wnt pathway, are detected mainly in the corneal endothelium (arrowheads in Fig. 2A-B), with less expression in the corneal epithelium (arrows in Fig. 2A-A’).