Sixty children with congenital hypothyroidism detected by neonatal thyroid: mental development at 1, 4, and 7 years: a longitudinal study.

A prospective study of mental development has been carried out in 60 unselected children with congenital hypothyroidism (C.H.) detected between 1976 and February 1985. Treatment with 1-thyroxin was initiated at the age of 10.4 +/- 2.5 days and supervised by T4 and TSH monitoring in 3-6 monthly intervals. Although clinical signs were mild or missing, skeletal maturation was prenatal in more than half. Developmental testing was carried out at 1, 4 and 7 years by the Brunet-Lezine (n = 60), the non-verbal Snijders-Oomen (n = 40), and the german version of the Wechsler intelligence test (n = 20), respectively. The global DQ/IQ in all but a few children at each age group are within the 3rd and 97th percentile of the DQ/IQ distribution in a control group tested during the same period of time. The mean values of all global and subscores, however, are lower than that one in the control group, differences being highly significant at 1 year. In 21 of our 60 children, associated findings and/or risk factors were present. The DQ/IQ in children without risk factors are identical to that of the control group. There are no significant DQ/IQ differences neither between athyroidism and ectopic thyroid glands, nor between prenatal bone age and normal skeletal maturation at diagnosis. We assume that the favourable results in our children with C.H. may be ascribed to the early onset of thyroid hormone replacement and the strictly controlled compliance.