Informing & Supporting Thyroid Patients Since 1985
Informing & Supporting Thyroid Patients Since 1985
Thyroid Research 
Thyroid Research Archive Development
(July 2003)
The background of the study. Absence (agenesis) of one lobe of the thyroid gland is a rare anomaly that is usually detected by thyroid imaging in patients thought to have a thyroid disorder. In this study, the frequency of thyroid hemiagenesis was determined in a population-based group of healthy children.
How the study was done. Between 1999 and 2001, 24,032 children (12,280 girls, 11,752 boys) aged 11 to 14 years living in Sicily underwent thyroid ultrasonography as part of a study of iodine nutrition. The length, depth, and width of both thyroid lobes were measured, and the volume was calculated as the volume of an ellipsoid ( /6 x length x depth x width). Thyroid hemiagenesis was defined as complete absence or marked hypoplasia (volume <10 percent of that of normal) of a thyroid lobe. Serum free thyroxine (T4), free triiodothyronine (T3), and thyrotropin (TSH) were measured in most of the affected children and in 18 age- and sex-matched normal children.
The results of the study. Twelve of the 24,032 children (0.05 percent) had thyroid hemiagenesis (seven boys [1:1678; 0.06 percent], five girls [1:2456; 0.04 percent]). Eleven children had complete absence of the left thyroid lobe, and one had severe hypoplasia of the left lobe. The volume of the remaining lobe in these 12 children was similar to the average total thyroid volume in normal children of the same age in 4 (33 percent), larger in 3 (25 percent), and smaller in 5 (42 percent).
All nine children in whom thyroid function was studied had serum TSH, free T4, and free T3 concentrations within the normal range, although their mean serum TSH and free T3 concentrations were slightly higher than in the 18 age-matched normal children.
The conclusions of the study. In this large group of children, all with thyroid hemiagenesis, had a missing left thyroid lobe, and most had some compensatory enlargement of the remaining lobe.
The original article. Maiorana R, Carta A, Floriddia G, Leonardi D, Buscema M, Sava L, Calaciura F, Vigneri R. Thyroid hemiagenesis: prevalence in normal children and effect on thyroid function. J Clin Endocrinol Metab 2003;88:1534-6.
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