Clinical symptoms include hair loss or lack of coat, over or under-weight, listlessness.
Research is currently ongoing to further understand the thyroid.
The thyroid tests currently available are diagnostic tests, rather than genetic tests. They simply tell us what the thyroid function was at a given point in time, much like a human cholesterol test. Just because our cholesterol level was ok today doesn't mean that it won't change or that we didn't inherit a tendency towards heart disease. The presence of autoantibodies is currently the only way to determine whether or not a dog's hypothyroid state is genetic. The current protocol is to begin testing for autoantibodies before age two, then yearly.