A population based in a region of Northern Ireland may have the highest proportion of giants on Earth due to rare mutation.In a region of Northern Ireland, there is a cluster of people having a genetic predisposition which causes them to abnormally grow tall.In Mid-Ulster, about 1 in 150 people carry a genetic mutation to the gene which leads to an overproduction of growth hormone resulting in acromegaly, also known as gigantism. This hormonal disorder is caused due to the failure of AIP gene (tumor supressor) and is spurred by a tumor on the pituitary gland, a pea-sized organ at the base of the brain.
Northern Ireland consists of the highest population of gaints in the world as quoted by Marta Korbonits, a professor of endocrinology at Barts and the London School of Medicine Queen Mary. Korbonits led the team which discovered the link between the AIP gene defect in Irish populations and gigantism in 2011.
In their last research, Korbonits and her team calculated that the AIP gene defect that traced back in 2,500 years. The team found the variant in Charles Byrne, a man born in 1761 who grew to be 7 feet, 6 inches tall and was known as the “Irish giant,” as well as in 18 other Irish families.
Symptoms vary depending on whether the disease first appears in childhood or as an adult. “The disease usually develops in children between 10 and 20, although we have a few cases younger than 10, and some between 20 and 30,” Korbonits explained.
In children, there’s rapid growth, that is accompanied by joint pain, disabling headaches, vision problems, type II diabetes, facial distortion and enlarged hands and feet. In adults, if symptoms develop late, adults don’t get taller, because their bones are already fused and may, in fact, shrink due to developing a curvature in the spine. Other symptoms include muscle weakness, hypertension and difficulty sleeping.
“While these people might look big and powerful and strong, the long-term effects of excess IGF-1 and growth hormone are very disabling for these patients,” explains Anthony Heaney, endocrinologist and professor at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA).
“We have this fascination with these really large, powerful people, and yet they themselves have a lot of morbidity and potential mortality from this disorder,” Heaney continues.
Treatments are available which includes surgery, medication or radiation therapy, but how effective those options depend largely on how the disease is progressing . Usually by that time, patients already have developed large tumors, and complete control of the tumor and hormone regulation is hard to achieve. Even the best surgical centers in the world are just 50 percent effective at achieving that control, Heaney notes.
Monitoring the lineage of the gene variant lets researchers keep an eye out for children who inherit the defect. Early clinical intervention can help to prevent the worst of the symptoms.
Researchers say it’s unlikely there are other hotspots with the same gene defect causing acromegaly.
“Humans have about 30,000 genes, and if you imagine that each gene is a book within a library, we have a library with 30,000 books, Korbonits explains. “The one which we’re talking about here is called AIP… and the Irish guys have one particular spelling mistake in this book.”
To Heaney, who hails from Northern Ireland, it made a lot of sense that a cluster of individuals prone to gigantism have been found in Mid-Ulster, not only because of the fame of giants like Bryne, but also the folklore of the region, specifically the myth of giant Fionn mac Cumhaill.
With researchers looking into the real, genetic heritage that inspired mythological figures and clinicians treating acromegaly, perhaps one day gigantism will only be found in fiction.
Source : Discovery News