Children may have insufficiency of GH secretion from birth or may acquire it later, either as a result (rarely) of a tumour in the area of the hypothalamus or pituitary or (more commonly) secondary to cranial irradiation.
A congenital deficiency may arise through deletion of the GH gene. Congenital insufficiency, which is the commonly encountered condition, is usually associated with pituitary hypoplasia secondary to a deficiency of the secretion of GH-releasing hormone from the hypothalamus.
The difference between deficiency and insufficiency is important since children with the former have no immunological tolerance to the GH molecule and thus develop antibodies when exposed to therapy.
