The world's oldest known case of Down syndrome has been found in the skeleton of a child who lived 1,500 years ago in medieval France.

French researchers found the skeleton of the 5-to-7-year-old child buried with dozens of others in an ancient necropolis near the Abbey of Saint-Jean-des-Vignes in eastern France, Live Science reported Thursday. The skeleton was discovered in 1989, but it wasn't until recently that scientists analyzed the skull to confirm the child had the genetic disorder.

The finding was published in June edition of the International Journal of Paleopathology.

Down syndrome occurs when a person has an extra copy of chromosome 21, which is associated with intellectual disabilities and characteristic facial features. The French child's skull was short, broad and flattened at the base, which are common signs of Down syndrome, Live Science reported.

Archaeologists also discovered how medieval societies treated those who had the genetic disorder. The child's body was positioned face-up, with the head turned west, the feet turned east and the hands placed under the pelvis- just like the rest of the 93 skeletons found in the necropolis.

This indicates the child was not treated like an outsider by the community.

"This Down syndrome child was not treated differently at death than others in the community," wrote lead author Maite Rivollat, according to ABC News. "We interpret this as a meaning that the child was maybe not stigmatized during life, the first time a Down syndrome individual has been so viewed in the context of the ancient community."

Though the child may be the oldest physical evidence of Down syndrome, artifacts from Mesoamerica indicate the disorder may have been known about centuries before that. The earliest depictions of the disorder are believed to be from Olmec figurines made around 1500 B.C., Live Science reported.