Hypoadrenocorticism (also known as Addison's disease) is a disease in Bearded Collies, although the inheritance is not known. It occurs when the adrenal cortex produces less then needed numbers of glucocorticoid and/or mineralocorticoid hormones. It affects approximately 2–3.4% of Bearded Collies in the USA/Canada, and causes the death of at least 1% of Bearded Collies in the UK. These are higher percentages than for the average dog population (0.1%), and hypoadrenocorticism causes a disproportionate number of deaths among young dogs. Early symptoms are vague and easily mistaken for other conditions. Symptoms include unexplained lethargy, frequent gastric disturbances, or an inability to tolerate stress. Untreated, hypoadrenocorticism can cause death. Thankfully, with medication, most dogs can live a normal life.