According to your son’s symptoms (extremely tired and sleepy, dry skin, constipation, short stature, coarse hair, hoarseness, cold intolerance, memory and concentration trouble, severe forgetfulness, delayed tooth development, paper thin nails, headaches, and moody) he might be experiencing congenital hypothyroidism but this must be confirmed with laboratory analyses of levels of Thyroid-Stimulating Hormones (TSH), Free Thyroxins (FT4) and Thyroxin Binding Globulins (TBG). To confirm hypothyroidism, FT4 levels must be under the normal reference values. TBG is also decreased in hypothyroidism. TSH can be increased in primary hypothyroidism or decreased in secondary hypothyroidism. In primary hypothyroidism, the problem is in the thyroid gland itself while in secondary hypothyroidism the problem is in the pituitary gland. Other examinations that have to be performed are an X-ray image of the long bones and a radio-scan of the thyroid gland. I can’t now make a judgment about your son’s laboratory reports because every laboratory has its own reference values when dealing with hormones. You can ask for expert help from a pediatrician-endocrinologist.