SCD is caused by mutations in the UBIAD1 gene (MIM *611632), encoding a membrane-embedded UbiA prenyltransferase domain-containing protein which catalyses the Mg2+-dependent transfer of a hydrophobic polyprenyl chain onto a variety of acceptor molecules, including vitamin K and coenzyme Q [1, 4, 5]. Here, UBIAD1 is linked to Schnyder corneal dystrophy.