1,000-year-old skeleton with condition causing small testes uncovered

The new discovery made in Portugal is the oldest case documented of Klinefelter Syndrome, a rare genetic condition.

 Early medieval skeleton (photo credit: Anni Byard/Oxfordshire County Council)
Early medieval skeleton
(photo credit: Anni Byard/Oxfordshire County Council)

A rare genetic condition that gives men an extra X chromosome has been uncovered in a 1,000-year-old skeleton in Portugal, making the discovery the oldest example of Klinefelter Syndrome - a rare condition that presents with small testicles. 

The finding was made during a collaborative study and was published Saturday in the journal The Lancet. 

To achieve their discovery, the team, run by Australian National University (ANU), examined genetic information obtained from a skeleton found in Portugal that had been radiocarbon dated to the 11th century by researchers from the University of Coimbra in Portugal, according to ANU.

"We were immediately excited the first time we looked at the results," study leader João Teixeira said. "However, ancient DNA is often degraded and of low quality and abundance, meaning we were initially cautious."

The researchers say the findings will help create a historic record for Klinefelter Syndrome, as well as improve understanding of its prevalence throughout human history.

 Flag of Portugal (illustrative). (credit: Wikimedia Commons) Flag of Portugal (illustrative). (credit: Wikimedia Commons)

What is Klinefelter Syndrome?

Klinefelter Syndrome is a rare genetic condition affecting only boys where individuals are born with an extra copy of the X chromosome, occurring in roughly one in 1,000 genetic-male births. The syndrome adversely affects testicular growth, resulting in smaller than normal testicles, which can lead to lower production of testosterone.  Those with the condition may also have learning disabilities, tend to be taller than average and are usually infertile as adults. 

"Ancient DNA, is often degraded and of low quality and abundance, meaning we were initially cautious."

João Teixeira

The research team expressed hope that their new method to examine the skeleton in Portugal can be improved and used down the road to study different chromosomal abnormalities in other archaeological finds, for example Down Syndrome.