Here is what I found, this is for humans although I believe it pertains to chickens as well to some level! In yo face, Cyprus!!
Gigantism :
Finding a specific
genetic cause for gigantism has proven to be difficult. Gigantism is the primary example of growth hormone hyper-secretion disorders, a group of illnesses that are not yet deeply understood.
[6]
Some common
mutations have been associated with gigantism. Pediatric gigantism patients have shown to have duplications of genes on a specific chromosome, Xq26. Typically, these patients also experienced an onset of typical gigantism symptoms before reaching the age of 5. This indicates a possible linkage between
gene duplications and the gigantism.
[18]
Additionally, DNA mutations in the aryl hydrocarbon receptor interacting protein (
AIP) gene are common in gigantism patients. They have been found to be present in about 29 percent of patients with gigantism.
[7] AIP is labeled as a
tumor suppressor gene and a
pituitary adenoma disposition gene.
[7][19]
Mutations in AIP
sequencing can have deleterious effects by inducing the development of pituitary adenomas which in turn can cause gigantism.
[7][19]
Two specific mutations in the AIP gene have been identified as possible causes of pituitary adenomas. These mutations also have the ability to cause adenoma growth to occur early in life.
[20] This is typical in gigantism.
Additionally, a large variety of other known genetic disorders have been found to influence the development of gigantism such as
multiple endocrine neoplasia type 1 and 4,
McCune-Albright syndrome,
Carney complex, familial isolated pituitary adenoma, X-linked acrogigantism (X-LAG).
[7][21]
Although various gene mutations have been associated with gigantism, over 50 percent of cases cannot be linked to genetic causes, showing the complex nature of the disorder.
[6]
