This assignment eventually led to the identification of mutations in the SLC4A11 gene as the genetic basis of CHED [5]. SLC4A11 encodes a membrane protein that was originally termed “BTR1” (Bicarbonate Transporter Related protein 1): a name that reflects its membership in the SLC4 family of bicarbonate transporting membrane proteins [26]. This evidence concerns the gene SLC4A11 and congenital hereditary endothelial dystrophy of cornea.