Remains show prehistoric peoples cared for those with Down syndrome
Gene-driven defects like Down syndrome have occurred among human beings for thousands of years, a new analysis of ancient DNA has revealed.
Not only did the birth defects exist, but these infants were often buried with care by their community. That suggests they were included as part of the community despite their differences, researchers said.
Six cases of Down syndrome and one case of Edward syndrome — a more severe genetic condition — have been found in the surviving DNA of human populations living in Spain, Bulgaria, Finland and Greece as long as 4,500 years ago, researchers said.
These results came from DNA analysis of about 10,000 ancient humans looking for autosomal trisomies, a birth defect in which people carry an extra copy of one of the first 22 chromosomes.
All of the cases were detected in infant burials, but from different cultures and time periods, researchers said.
Down syndrome occurs when a person is born with an extra copy of chromosome 21. It is associated with developmental delays, intellectual disability and a characteristic set of facial features, according to the Centers for Disease Control and Prevention.
“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,” said lead researcher Adam Rohrlach, a statistician at the University of Adelaide’s School of Mathematical Sciences in Australia.
The study was recently published in the journal Nature Communications.
“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,” said Roberto Risch, an archaeologist at The Autonomous University of Barcelona. “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.”