Graves' Disease Support Group
Graves-Basedow disease is a medical disorder that may manifest several different conditions including hyperthyroidism (over activity of thyroid hormone production), infiltrative exophthalmos (protruberance of one or both eyes and associated problems) and infiltrative dermopathy (a skin condition usually of the lower extremities). This disorder is the most common cause of...

HypO and HypER can happen back and forth according to which of the thyroid antibodies are currently active. The antibodies being either the stimulating or the blocking kinds.
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If you have Graves Disease and your father has Hashimoto’s Disease, they are both auto-immune diseases. I have experienced both sides. There were times when I had the hyper symptoms and then get the hypo symptoms - this went on for many years but I was diagnosed until the beginning of 2018. BTW, my dad was diagnosed when he was 60 (30 years ago) and me just recently. This runs in the family.