gigantism /jigan″tizəm/ [L, gigas, giant] , an abnormal condition characterized by excessive size and stature. It is caused most frequently by hypersecretion of growth hormone (GH) that occurs before the closure of the bone epiphyses; it occurs to a lesser degree in hypogonadism and in certain genetic disorders. Gigantism with normal body proportions and normal sexual development usually results from hypersecretion of GH in early childhood. Hypogonadism, by delaying puberty and closure of the epiphyses, may lead to gigantism. Excessive linear growth often occurs in males with more than one Y chromosome, and it may accompany Klinefelter’s syndrome, Marfan’s syndrome, and some cases of generalized lipodystrophy. Children with cerebral gigantism are cognitively impaired and have a large head and extremities and a clumsy gait. Growth is rapid during their first few years and then reverts to a normal rate. Appropriate gonadal hormones may be administered to control abnormal growth of children with hypogonadism. The treatment of acromegalic gigantism is usually irradiation or surgical removal of the GH-secreting adenoma. Compare acromegaly. See also eunuchoidism.
