Truth in the Folk Tales: Gigantism in Ireland has a genetic origin

A new study demonstrates that a benign growth on the pituitary gland causing a growth disorder called acromegaly, which in some cases may lead to gigantism, are often inherited in Northern Ireland. A genetic test on DNA samples can identify the presence of the gene presenting the risk.

An international team of scientists led by Prof. Márta Korbonits from Queen Mary University, London, reported key findings regarding pituitary tumours of genetic origin. The study, published in the journal Human Mutation and covered by the BBC and The Times, identified an increased number of patients with acromegaly and gigantism in the Mid Ulster region of Ireland (Figure 1) and demonstrates how a change in the gene called AIP was inherited from one single person, the "common ancestor", who lived approximately 2,500 years ago.

Figure 1. Map showing part of island of Ireland with the identified number of AIP gene carriers and acromegaly patients. Each of the 8 graphs on the left and right side of the map show data regarding subjects living in the area marked by the blue arrows. Each graph has 3 columns. The green column represents subjects who carry the AIP gene but not affected by the disease. The red bar represent subjects who have acromegaly/gigantism and harbour the "Irish" AIP mutation. The blue bar represents patients with acromegaly but without the AIP mutation.

These findings may explain the known historical accounts of Irish giants originating from the area and, in a way, justifies the numerous local legends involving giants. Historical accounts include Mary Murphy (cca. 1696) from Portrush, James Kirkland (cca. 1730) from Ballygar as seen on the painting by Johann Christof Merk, Charles Byrne (1761-1783) from Littlebridge near Cookstown who was proven to have the genetic alteration, Byrne's cousins the Knipe twins, both suffering from gigantism, Big McGee (cca. 1800) from Clogher, mentioned in James Carleton autobiography and also in a poem by Benjamin Lynass (1842), Patrick Murphy (1834 - 1862) from Killowen, and also two 'new' examples are shown in Figure 2 & 3.

Figure 2. A patient with gigantism born in Magherafelt from 1910.

Figure 3. Photograph from Garvagh museum showing 2 patients with typical features of acromegalic gigantism, the person the middle with the pole and the one on the left in white shirt and tie.

The scientists, helped by local volunteers, tested over 900 people living in the Mid Ulster area and 3000 more Irish individuals. They have identified gene carriers, including some without any symptoms. Some of these subjects have family members with gigantism.

Calculations based on data gained from the collected DNA samples predict there are approximately 432 persons of Irish ancestry who currently could carry the gene. Not all subjects with the gene would develop the disease, but in the subjects where it does develop (20-30%), early diagnosis is key to successful treatment. These data suggest that testing of young Irish patients with acromegaly and their relatives would be beneficial, while screening of entire populations is not recommended.

The study was successful in creating disease awareness of the local general public and medical professionals, a key requirement for early recognition and treatment of this condition.