Gigantism is a rare growth disorder characterized by excessive height and growth significantly above average. This condition results from an overproduction of growth hormone (GH) during childhood or adolescence. The primary focus of understanding gigantism often revolves around its infrequency, marking it as an uncommon medical condition.
Understanding Gigantism
Gigantism stems from an excessive secretion of growth hormone (GH), typically caused by a benign tumor on the pituitary gland, known as a pituitary adenoma. This overproduction of GH occurs before the growth plates in the long bones have fused, which usually happens after puberty. The elevated GH levels accelerate the growth of muscles, bones, and connective tissues, leading to an abnormally increased height.
Individuals with gigantism often exhibit distinct physical characteristics due to this accelerated growth. They experience unusually rapid height increase and develop disproportionately large hands and feet. Other common features include a prominent forehead and jaw, along with a thickening of facial features such as an enlarged nose, lips, and tongue. Beyond these visible changes, individuals may also experience symptoms like headaches, vision problems, joint pain, and excessive sweating. Delayed puberty and irregular menstruation are also reported in some cases.
Global Prevalence and Incidence
Gigantism is considered an ultra-rare condition, making its precise global prevalence and incidence challenging to determine. Its rarity means that the total number of reported cases worldwide is only in the hundreds. The incidence of gigantism is estimated to be approximately 8 new cases per million person-years.
Obtaining exact global statistics for such rare diseases is difficult due to potential underdiagnosis in various regions and the limited number of affected individuals. Despite these challenges, available data consistently confirm gigantism as an exceptionally uncommon pediatric condition.
Gigantism Versus Acromegaly
Both gigantism and acromegaly result from the excessive production of growth hormone (GH), primarily due to a pituitary adenoma. The fundamental distinction between these two conditions lies in the timing of the GH hypersecretion relative to skeletal development. Gigantism occurs when the excess GH is produced during childhood or adolescence, before the epiphyseal growth plates in the bones have closed. This early onset leads to an overall increase in linear growth, resulting in significantly increased height.
Conversely, acromegaly develops when GH hypersecretion begins in adulthood, after the growth plates have already fused. Since linear growth is no longer possible, the excess GH in acromegaly causes the disproportionate enlargement of certain body parts, such as the hands, feet, and facial features, rather than an increase in height.