Gallbladder mucocoele (GBM) causes an abnormal accumulation of inspissated bile and/or mucous within the gallbladder. Older, small- to medium-breed dogs seem to be predisposed. Clinical signs are often non-specific and include vomiting, lethargy, anorexia, abdominal pain, jaundice and excessive drinking and urinating. If left untreat, or the gallbladder ruptures, it can cause death. As an autosomal dominant disease with incomplete penetrance, it is know that dogs inheriting one copy of the causal mutation are at increased risk for the disease. However, the disease development and onset varies between dogs, and not all dogs with one copy of the mutation will go on to develop the disease. It is possible environmental or other factors (genetic or not) impact the clinical expression of the disease.