Down syndrome identified in prehistoric bones of infants through DNA

The remains of one of the individuals, "CRU001", a boy who died at or shortly before birth and was buried in Alto de la Cruz, Navarre, Spain.

Researchers have diagnosed Down Syndrome in the bones of children born approximately 5,000 years ago.

Most notably, the children were given noble burials and treated with "care and appreciation," according to a recent study published in the journal Nature Communications.

The team of scientists say that six cases of Down syndrome were identified in human populations living in Spain, Bulgaria, Finland, and Greece thousands of years ago. 

What is Down syndrome?

According to the Centers for Disease Control and Prevention, Down syndrome is a condition in which a person is born with an extra chromosome. Typically, a baby is born with 46 chromosomes. 

People born with Down syndrome typically have a moderate-to-low IQ and have distinctive physical features, which can include: 

  • A flattened face, especially the bridge of the nose
  • Almond-shaped eyes that slant up
  • A short neck
  • Small ears
  • A tongue that tends to stick out of the mouth
  • Tiny white spots on the iris (colored part) of the eye
  • Small hands and feet
  • A single line across the palm of the hand (palmar crease)
  • Tiny pinky fingers that sometimes curve toward the thumb
  • Poor muscle tone or loose joints
  • Shorter in height as children and adults

Why is this study critical?

These remains represent the oldest case of Down syndrome ever recorded in humans.

Researchers say in the past, it's been challenging to diagnose ancient remains with a disease like Down syndrome. 

"While we expected that people with Down syndrome certainly existed in the past, this is the first time we’ve been able to reliably detect cases in ancient remains, as they can’t be confidently diagnosed by looking at the skeletal remains alone," says Dr Rohrlach, a statistician from the University of Adelaide’s School of Mathematical Sciences. 

The specific burials they found and the care that went into them indicates the importance the children had in the society at the time. 

Researchers noted that most people in the region were cremated at the time.

"We don’t know why this happened, as most people were cremated during this time, but it appears as if they were purposefully choosing these infants for special burials," says Professor Roberto Risch, co-author and archaeologist from The Autonomous University of Barcelona.

Researchers also found one case of Edwards syndrome in the Early Iron Age in Spain. 

Edwards syndrome is another genetic condition that causes physical growth delays during fetal development. 

"The remains could not confirm that these babies survived to birth, but they were among the infants buried within homes at the settlement, or within other important buildings," Risch continued.