Based on results from Lucas' most recent bloodwork, his endocrinologist told us that as of now Lucas does not have autoimmune thyroid disease (hypothyroidism) -- he tested negative for antibodies. However, his TSH level is higher than it was last time (now at 8.89) although his T3 (143) and T4 (1.2) levels are well within normal range. The doctor said the TSH level sometimes fluctuates in people with Down syndrome and they don't require treatment. In fact, sometimes the issue even resolves on its own.
Lucas will be rechecked in three months and if he continues to have elevated TSH level, then the endocrinologist will order a thyroid nuclear scan to investigate further. The doctor said he generally will treat anyone with a TSH level above 10; he added that people with Down syndrome most often present with thyroid dysfunction between 5-6 years old or during adolescence. Given how important the thyroid is to so many aspects of development, we will keep a close eye on it and treat Lucas if/when the need arises.