BONE METABOLISM IN CHILDREN WITH CONGENITAL HYPOTHYROIDISM - A LONGITUDINAL-STUDY

In order to evaluate the effect of thyroid replacement therapy on bone metabolism in congenital hypothyroid children, we studied 23 (10 girl s and 13 boys) consecutive patients, Their age ranged from 3 to 8 week s. One of these patients had familiar dyshormonogenesis, 21 had ectopi c glands and one hemiagenesis, As a control group, we studied 46 sex- and age-matched healthy newborns. Before the beginning of therapy, the hypothyroid patients showed higher values of calcium (2.78 +/- 0.04 v s 2.65 +/- 0.07 mmol/l; p < 0.05) and of 1,25-dihydroxy-vitamin D (159 .7 +/- 31.6 vs 90.5 +/- 33.1 ng/l; p < 0.01), while they showed lower values of osteocalcin (1.9 +/- 0.8 vs 2.9 +/- 0.9 ng/ml; p < 0.01) tha n controls, After 3 months of therapy, we found a complete normalizati on of all these parameters and a progressive increase of osteocalcin. Our data show that in congenital hypothyroid children there are abnorm alities in calcium metabolism which seem to be transient and reversibl e after L-thyroxine replacement therapy.