Around the holidays, Lucas went in for his three year check-up where blood work turned up an elevated TSH (thyroid stimulating hormone which controls thyroid function), which may be a warning sign of impending hypothyroidism (an auto-immune disease resulting in an underactive thyroid gland). They also measured T3 (active hormone) and T4 (thyroxine) which both came back within normal limits. He was referred to an endocrinologist who we went to see today. The doctor is now running further tests to check for antibodies ; the presence of antibodies may indicate hypothyroidism.
Hypothyroidism is common in people with Down syndrome. In fact, our friends' daughter, Krysta (who is 5), recently went to see the same endocrinologist because she also had an elevated TSH level.
The thyroid regulates growth and development as well as metabolism so we need to keep a very close eye on this potential issue. Lucas is not displaying any of the symptoms of an under-active thyroid. For now, Lucas continues to make good progress developmentally and is growing between the 25-50 percentiles with his weight at about the 50th percentile on the typically developing growth chart (kids with Down syndrome tend to be smaller and often are plotted on a different growth chart). We want to keep it that way.
If he needs treatment, it will be in the form of a replacement of thyroid hormone and the dose will need to be monitored by sequential blood tests to see how the thyroid responds. Although treatment is needed for life, at least it's something that can be treated effectively.
I'll post results when I have them.