Recently on the Thyroid Health forum, a member asked about hereditary thyroid disease and what their chances were, as the child of a thyroid disease parent, for eventually experiencing the onset of the disease. I felt the thread would make a good feature article and a good one for the BellaOnline Thyroid Health archives. The information that came from that forum thread follows below.

According to Dr. Hossein Gharib, M.D. of the American Association of Clinical Endocrinologists and Professor at the Mayo Medical School, “Fifty percent of thyroid disease patients’ offspring will inherit the thyroid disease gene.” I actually didn't know that chances for children of thyroid disease parents were at 50% risk until I found that quote from the MD above. I knew it was a high percentage risk but 50% was surprising. That's not great news for children of thyroid disease parents but shows the importance of getting blood tested at any point thyroid type symptoms arise and if they don't manifest earlier, to start getting tested at age 35 regardless.

Some reputable thyroid statistics state that between ages 35 and 40 is a common age for the onset of thyroid disease. If you are the child of a parent or parents with thyroid disease, you should educate yourself about thyroid disease symptoms, so that you can recognize when there is a need to be tested, before age 35.

In my opinion, when symptoms arise in someone at risk for developing thyroid disease, they should have not only tests ordered for thyroid function but also the ones to detect "thyroid antibodies". These are the killer cells the immune system creates and sends out to attack what it perceives as invaders in the body (e.i. viruses & allergens). In the case of autoimmune thyroid disease, it recognizes the thyroid as one of those invaders. These antibodies can cause thyroid disease symptoms in advance of causing eventual thyroid hormone imbalance and is why I believe they are important to have tested.

The thyroid antibodies that should be tested for are the "anti-thyroidperoxidase" (TPO),"anti-thyroglobulin" (TG) and "thyroid stimulating imunnoglobulins" (TSI). Those first two are common findings (found to be positive) in autoimmune hypothyroidism or “Hashimoto’s thyroiditis”, while that third one is more commonly found in people with autoimmune hyperthyroidism or Grave’s Disease, so depending upon the symptoms one is having, they may want only certain ones tested for.

The thyroid function tests, that detect thyroid hormone imbalances, are the "TSH", "T-4" and "T-3" levels. Some Doctors believe the "Free" levels of the T-4 and T-3 are best and from what I've read, I agree with them. These are the ones I have tested in follow up on my thyroid hormone therapy for hypothyroidism but are good for diagnosing thyroid disorders as well. If only one test is used to evaluate thyroid function, it will usually be the TSH level. This one is the pituitary hormone that accurately reflects how well the thyroid gland is supplying hormone to the body and is sensitive in that it usually detects a change in thyroid function earlier than any other tests.