Analysis of physical and mental development of children with aplasia, hypoplasia and ectopy of the thyroid gland.

Objective: Evaluation of clinical and biochemical differences between various forms of thyroid dysgenesia in children.

Methods: The study involved 102 children at the age between 4.8 and 14.2 years who were born with congenital hypothyroidism (CH), as diagnosed by neonatal screening examinations. In all the children diagnosis was settled and the levothyroxine (L-T4) administration was started by the 19th day of life. Out of the examined children, 79 were selected with following three forms of developmental thyroid disorders: Group I--athyroidism (thyroid aplasia or agenesis), Group II--thyroid hypoplasia, Group III--thyroid ectopy. On the basis of neonatal TSH (nTSH) levels obtained by screening and serum TSH, FT4 and Tg concentrations, the severity of hypothyroidism was determined at the time of diagnosis. Physical and mental development of the children was evaluated on the basis of growth and bone age indices and Wechsler's scale, respectively.

Results: Developmental disorders were diagnosed in 79 cases (77.4% CH) which included 45 cases (44.1%) of athyroidism, 31 cases (30.4%) of thyroid hypoplasia and 3 cases (2.9%) of thyroid ectopy. The physical and mental development in the studied groups was evaluated as normal.

Conclusions: In the group of children with athyroidism, significantly lower growth indices and IQ values were found in comparison with respective values observed in the other study groups. However, the indices of physical and mental development in all the studied groups were within the normal values for children population. An early diagnosis and early administration of hormonal replacement therapy by L-T4 ensure normal development of children with CH, regardless of underlying causes and associated with them severity of congenital hypothyroidism.