Growth hormone excess is typically associated with gigantism and acromegaly. Gigantism is an abnormal high linear growth due to excessive action of hGH and IGF‑1 while the epiphyseal growth plates are open during childhood resulting in tall stature.
Acromegaly is the same disorder of hGH and IGF‑1 excess when it occurs after the growth plate cartilage fuses in adulthood. The clinical manifestations of acromegaly range from subtle signs, such as acral overgrowth and coarsening of facial features, to significant metabolic, cardiovascular, and respiratory manifestations, leading to an increase in morbidity and mortality.
Growth hormone deficiency (GHD) in children results in retardation of longitudinal growth compared to bone age whereas severe GHD in adults is associated with reduced muscle strength and bone mass, insulin sensitivity, abdominal adiposity and increased cardiovascular risk factors (i.e. abnormal lipid profile, atherosclerosis).