The progressive ankylosis gene (Ank; ANKH in humans) encodes a multipass transmembrane protein (ANK) that was reported to regulate the transport of intracellular PPi to extracellular spaces (Gurley et al., 2006; Gurley, Reimer, & Kingsley, 2006; Ho, Johnson, & Kingsley, 2000), and, more recently, proposed to transport adenosine triphosphate (ATP) to the extracellular compartment (Szeri et al., 2022). This evidence concerns the gene ANKH and ankylosis.