Gigantism gene inherited by hundreds: Study

By Dr. Ananya Mandal, MDJan 9 2011

A gene that predicted gigantism in humans was identified in the DNA of the 18th-century man known as the Irish Giant, who was more than 7 feet 7 inches tall. Copies of the same mutation have been found in patients today who suffer from excessive growth, and scientists have concluded they all inherited the gene from a common ancestor.

18th-century surgeon John Hunter obtained the skeleton of giant Charles Byrne, who was born in Northern Ireland in 1761 after his death at the age of 22 and is now at the Hunterian museum at the Royal College of Surgeons in London.

Scientists now have tested his DNA from two of his teeth and found a mutant version of a gene known as AIP. This matched those found in living patients from four Northern Irish families. This gene leads to tumours of the pituitary gland at the base of the brain, which regulates growth hormone. The tumours can cause abnormal growth and side-effects including thickened skin, osteoarthritis, and premature death from heart disease. The British researchers write in The New England Journal of Medicine that all carriers of the mutant AIP gene had inherited the fault from a common ancestor who lived about 1,500 years ago.

Lead researcher Marta Korbonits of Barts and The London School of Medicine and Dentistry estimated that several hundred people might carry the gene today. She said, “The most important clinical aspect of our study is that it is now possible to trace down carriers of this gene and treat patients before they grow to be a giant.” Co author, Mark Thomas of University College London said, “With modern genetic techniques we can say so much about somebody who died so long ago and use that information to treat people today.”

“There is nothing solid scientifically,” said Dr. Constantine Stratakis, a geneticist and pituitary tumor researcher who is the acting scientific director for the Division of Intramural Research at the National Institute of Child Health and Human Development. And for unknown reasons, only about 30 percent of people with the mutated gene develop tumors.