Ancient Embrace Reveals Genetic Roots of Rare Disorder in Stone Age Pair

More than 12,000 years ago, two closely-related women – likely a mother and daughter – were buried in an embrace at the Grotta del Romito cave in southern Italy. This Ice Age pair of hunter-gatherers were both shorter than average for their population, with one exhibiting markedly reduced stature. Now, researchers have identified the genetic cause of their differing heights, shedding light on a rare inherited condition and the care provided within Stone Age communities.

Unearthing a Familial Genetic Case

A team of European researchers re-examined the skeletons, first discovered in 1963, using modern genetic techniques. Analysis of ancient DNA recovered from the inner ear of each individual revealed that both were female and first-degree relatives [1]. The younger of the two, nicknamed Romito 2, was diagnosed with acromesomelic dysplasia, Maroteaux type (AMDM), a rare genetic disorder affecting bone growth. This represents the earliest known evidence of the condition.

The Genetics of AMDM

AMDM is caused by mutations in the NPR2 gene, which provides instructions for making a protein involved in skeletal development [1]. Without two functional copies of this gene, the protein isn’t produced, leading to the physical characteristics associated with AMDM. The older woman, Romito 1, carried one non-functional copy of the NPR2 gene, resulting in moderately reduced stature.

A Family Story Revealed

The genetic analysis suggests that if Romito 1 is the mother of Romito 2, the father also carried at least one copy of the mutated NPR2 gene. This explains how Romito 2 inherited two copies – one from each parent [1]. The discovery highlights how the same gene can affect family members differently depending on whether they have one or two copies of the mutation.

Challenges and Care in the Stone Age

Living as a hunter-gatherer, Romito 2 would have faced significant challenges due to her condition. The skeletal features associated with AMDM limited her range of motion, particularly at the elbows and hands, making daily activities more difficult [1]. Despite these difficulties, she survived until late adolescence, suggesting she received care and support from her family group.

Evidence of Early Social Care

The researchers emphasize that the survival of Romito 2 points to the existence of social care within Stone Age communities. “She survived… until late adolescence with a diet and nutritional stress similar to that of other Romito persons, which suggests that the challenges she faced were met by the provision of care in her family group,” stated the study authors [1]. This finding adds to growing evidence that humans have been caring for one another long before the advent of civilization.

The Grotta del Romito: A Window into the Past

The Grotta del Romito, a limestone cave in the Lao Valley of Pollino National Park in Calabria, Italy, has been a significant archaeological site since its discovery in 1961 [2]. Excavations have revealed evidence of prolonged human occupation dating back 17,000 years, encompassing both the Upper Paleolithic and Neolithic periods [2]. The cave also contains Upper Paleolithic parietal rock engravings and other burial sites [2], [3].

Implications for Modern Medicine

“Rare genetic diseases are not a modern phenomenon but have been present throughout human history,” says Dr. Adrian Daly of Liège University Hospital Centre in Belgium. “Understanding their history may help recognizing such conditions today.” [1] This research, published in The New England Journal of Medicine, demonstrates the power of ancient DNA analysis to reveal insights into both the past and the present.