MEOX1 and MEOX2 are homeodomain transcription factors that have been shown to be partially functionally redundant during development. They regulate the cyclin dependent kinase inhibitors p21 and p16 in vascular endothelial cells []. Nevertheless, MEOX1 also plays important, non-redundant roles in maintaining sclerotome polarity and the formation of cranio-cervical joints []. Mutations in the MEOX1 gene cause Klippel-Feil syndrome 2, autosomal recessive (KFS2), a skeletal disorder characterised by congenital fusion of cervical vertebrae [, ].
