Evolution of height and bone age in primary congenital hypothyroidism

Thyroid hormones are fundamental for growth and bone maturity. Retarded physical and osseous development signals congenital hypothyroidism. This study assessed the evolution of height and bone age and final height after hormone replacement treatment in 25 patients with primary congenital hypothyroidism. Bone ages, measured periodically for 12 years after treatment began, were expressed as standard deviation scores (SDS) corresponding to chronologic age. Heights were expressed as SDS and related to standardized curves and genetic height. All patients experienced height recovery during the first year. Of 19 patients who reached their final height, 16 surpassed the expected mean for genetic height. Bone age accelerated progressively, with total recovery toward the third year, and remained accelerated, reaching +1.43 +/- 1.27 in relation to chronologic age 12 years after hormone replacement began. Thus, early diagnosis and adequate treatment of congenital hypothyroidism improved growth and osseous development, although progressive acceleration of bone age may have limited final height in some children.