Females are more affected than males and often fall within the six to eight year age group. Initial clinical signs are increased thirst and urination and an increase in body weight. Later observable is a change in body type, a pot bellied appearance, thinning of the dog's coat and other changes involving the skin. All of this is related to over production of adrenal cortex hormones. Various medications are available to counteract this over production.
Hypothyroidism is the number one inherited disease of dogs in general.
The metabolism is affected, causing depression, weight gain, hair loss, lethargy and an intolerance to cold. Untreated, it can lead to immune system, cardiovascular, and reproductive problems. Testing and treatment is relatively easy and inexpensive. Daily medication can give good results and many dogs live healthy lives. When it occurs in young dogs or several members of a family, a genetic cause is likely.