Elliptocytosis is a mild disorder which causes red blood cells to be formed oval-shaped (elliptocytes) instead of in the typical round “biconcave” shape. While typically harmless by itself, the disorder can leave affected dogs more vulnerable to other cardiovascular disorders. This variant of elliptocytosis, observed in a Labrador/Chow mixed-breed dog, is believed to be caused by a dominant mutation to the SPTB gene.