Amazing coincidence discovered in a long-lost medieval cemetery: ScienceAlert

In 2003, workers are building a highway through a small town in Ireland by accident a long-lost medieval cemetery.

Of the approximately 1,300 bodies found at the site near the township of Ballyhanna, a few ancient burials stood out. Their bones were riddled with benign tumors caused by a rare disease, but for strangely different reasons.

Both individuals appear to have a genetic condition known as multiple osteochondromaswhich causes the growth of painful but typically non-malignant tumors in the bones, which eventually leads to limb deformities, postural problems or nerve damage.

Today we know that the disease is far from common, occurring in approximately one in 50,000 people. Finding two bodies in such a condition in such a small cemetery is a real coincidence, especially since the genome analysis of the remains was published in European Journal of Human Genetics finds that the two men who left the bones were not closely related.

Namely, their lives in this small Irish parish were separated by several centuries.

“We made several assumptions about these two men when we first realized that they both suffered from multiple osteochondromas,” explains archaeologist Eileen Murphy of Queen’s University Belfast, senior author of the study.

“We assumed they were contemporaneous, but radiocarbon dating showed they were several hundred years apart. We also assumed they were related but new [ancient DNA] analysis has shown that this is not the case.”

None of the skeletons excavated from the lost Ballyhanna family burial ground appear to have been in particularly good health when they died. Some show evidence from tuberculosis or rickets.

But the bones of the two men with bony growths were in particularly poor health.

Archaeologists suspect that the cemetery was once part of a lower-class Gaelic medieval community that included men, women and children. Some individuals were probably very poor, while others worked as farmers, laborers, merchants, artisans or priests.

The discovery of two unrelated men with the same rare bone disease in such a small community is unusual in itself, and it gets even stranger.

Despite their similar appearance, a recent analysis revealed that the two cases of multiple osteochondroma are not even caused by the same genetic mutation.

Both individuals showed changes in the EXT1 gene, which is associated with multiple osteochondromas. But one of the mutations has never been seen in modern patients.

The first human had a missense mutation in part of his EXT1 gene, where one nucleotide base was replaced by another, the coding sequence for the protein. It has previously been identified in at least three contemporary patients with multiple osteochondromas.

Another man showed a premature stop message in the same gene that had not yet appeared in modern sequencing data from patients with the disease.

The individual with the new mutation died at a younger age, between 18 and 25 years of age, and showed deformities in the hips, knees, ankles and forearms. He lived somewhere between 1031 and 1260.

The individual who died at an advanced age, around 30 or 40 years old, had less pronounced tumors, but they were visible all over the skeleton. He lived between 689 and 975.

“It was really surprising that these individuals had completely different mutations that caused their condition, especially because it’s so rare,” he says geneticist and first author Iseult Jackson from Trinity College, Dublin.

This discovery just goes to show how much modern DNA analysis can reveal about diseases that have been with us for millennia.

“The study shows the important contribution that analyzing ancient DNA from people from the past can make to understanding conditions that still affect people today,” says Trinity College Dublin geneticist Dan Bradley.

The study was published in European Journal of Human Genetics.