Researchers at the Francis Crick Institute have identified the oldest known case of the mosaic form of Shereshevsky-Turner syndrome, dating back roughly 2,500 years. The discovery is detailed in a new study published in a scientific magazine.
Shereshevsky-Turner syndrome, commonly called Turner syndrome, is a chromosomal condition where a girl is missing all or part of one X chromosome. Typical features include short stature, nonfunctional ovaries leading to infertility, and distinctive physical signs such as folds of skin on the neck, very sparse hair at the back of the head, a droopy upper eyelid, a skin fold at the inner eye corner, and ears that tilt forward. The condition is not usually inherited; it generally arises during fetal development.
The ancient case was uncovered using a novel computational approach that counts copies of the X and Y chromosomes in ancient DNA samples. The researchers examined several ancient individuals and were able to identify aneuploidy, or abnormal chromosome numbers, in six of them, with five showing variations in sex chromosome counts.
Among the findings, three individuals were identified with Klinefelter syndrome, a condition in males caused by an extra X chromosome. The oldest identified case of Jacobs syndrome, also known as XYY syndrome, was discovered in a man who lived about 1,200 years ago.
Earlier reports mentioned an ancient discovery in China described as the oldest recorded portion of a multiplication table, illustrating the breadth of historical genetic investigations that illuminate human biology across eras.