The important role that GH and its receptors play in human development is very well illustrated by disease states that are caused by either growth hormone deficiency or hypersecretion:
Growth Hormone Deficiency
Deficiency in growth hormone or defects in its receptor result in growth retardation or dwarfism.
The manifestation of growth hormone deficiency depends upon the age of onset
of the disorder and can result from either heritable or acquired disease. The characteristic features of these disorders is short stature which is clinically-defined as an adult height of less than 147 cm. Probably one of the best known people with this disorder is the American actor Peter Dinklage 
who plays Tyrion Lannister in George R. R. Martin's Game of Thrones .
Growth Hormone Hypersecretion
Hypersecretion of growth hormone is manifest by two distinctive disorders that are differentiated by the age at which the elevated GH levels occur:
Gigantism is the result of excessive growth hormone secretion that begins in young children or adolescents and usually arises from a tumour affecting the pituitary gland. Hussain Bisad
.
Acromegaly results from excessive secretion of growth hormone in adults. This produces an increase in bone diameter (although not length) and hypertrophy in other tissues such as cardiac and skeletal muscle. Not surprisingly these changes result in a marked change in appearance