Klinefelter syndrome is a rare genetic disorder that results in the presence of an extra X sex chromosome in genetically male individuals. In the archaeological context, some alleged cases would have been detected, such as the Finnish warrior from Suontaka Vesitorninmäki – based solely on the analysis of genetic material. A study recently published in the lancet It provides new elements to diagnose Klinefelter syndrome on even more grounded bases, since it combines for the first time three types of tests: genetic, but also morphological and osteological. The international team of researchers, coordinated by the Portuguese geneticist João C. Teixeira, currently stationed at the Australian National University in Canberra, has thus identified the presence of an additional X chromosome in a man who lived in Braganza, in northeastern Portugal. about a thousand years ago The development of a new method to determine genetic characteristics in the framework of this study could serve in the future as a basis for identifying genetic diseases in other contexts where DNA is fragile or degraded, such as medical, legal or prenatal diagnosis.
A genetic abnormality, Klinefelter syndrome, would have been identified in a man of the Middle Ages
The individual studied by the international team that brings together archaeologists, anthropologists, geneticists and statisticians was buried in the Torre Velha archaeological site, a necropolis excavated between 2012 and 2015 by researchers from the University of Coimbra. Located on the outskirts of the city of Bragança, Torre Velha is now considered one of the most remarkable places in the Trás-os-Montes region of northeastern Portugal. So far, 59 burials have been unearthed there, mainly individual graves, but also ossuaries grouping together several individuals. They were dug directly into the shale rock,”which is typical of medieval sites in Iberia“, reveals the study; Carbon 14 dating indicates that the burials occurred between the 6th and 13th centuries AD.
The individual who caught the researchers’ attention would have been buried between the 11th and 12th centuries, authorizing mass spectrometer dating to a margin of between 1020 and 1160 AD It was placed in an oval-shaped tomb, the researchers write, who did not find neither cover nor funerary furniture. His burial in a recumbent position, with his arms crossed over his chest and oriented from west to east, corresponds to Christian custom.
The man was buried with his arms crossed over his chest.. © João C. Teixeira et al. / the lancet
An extra X chromosome
Klinefelter syndrome is a rare genetic disorder that results in the presence of an extra X sex chromosome in genetically male individuals. In the archaeological context, some alleged cases would have been detected, such as the Finnish warrior from Suontaka Vesitorninmäki – based solely on the analysis of genetic material. A study recently published in the lancet It provides new elements to diagnose Klinefelter syndrome on even more grounded bases, since it combines for the first time three types of tests: genetic, but also morphological and osteological. The international team of researchers, coordinated by the Portuguese geneticist João C. Teixeira, currently stationed at the Australian National University in Canberra, has thus identified the presence of an additional X chromosome in a man who lived in Braganza, in northeastern Portugal. about a thousand years ago The development of a new method to determine genetic characteristics in the framework of this study could serve in the future as a basis for identifying genetic diseases in other contexts where DNA is fragile or degraded, such as medical, legal or prenatal diagnosis.
A genetic abnormality, Klinefelter syndrome, would have been identified in a man of the Middle Ages
The individual studied by the international team that brings together archaeologists, anthropologists, geneticists and statisticians was buried in the Torre Velha archaeological site, a necropolis excavated between 2012 and 2015 by researchers from the University of Coimbra. Located on the outskirts of the city of Bragança, Torre Velha is now considered one of the most remarkable places in the Trás-os-Montes region of northeastern Portugal. So far, 59 burials have been unearthed there, mainly individual graves, but also ossuaries grouping together several individuals. They were dug directly into the shale rock,”which is typical of medieval sites in Iberia“, reveals the study; Carbon 14 dating indicates that the burials occurred between the 6th and 13th centuries AD.
The individual who caught the researchers’ attention would have been buried between the 11th and 12th centuries, authorizing mass spectrometer dating to a margin of between 1020 and 1160 AD It was placed in an oval-shaped tomb, the researchers write, who did not find neither cover nor funerary furniture. His burial in a recumbent position, with his arms crossed over his chest and oriented from west to east, corresponds to Christian custom.
The man was buried with his arms crossed over his chest.. © João C. Teixeira et al. / the lancet
An extra X chromosome
The genetic material extracted from the skeleton was analyzed in a specialized laboratory at the Australian Center for Ancient DNA (ACAD), at the University of Adelaide (Australia). Several methods were applied to obtain the most relevant result possible. In particular, the researchers used a new Bayesian method, which is based on probabilities, to assign a karyotype based on the sequenced DNA fragments. They thus concluded that, according to a probability of the order of almost 100%, the individual carried 47 chromosomes, instead of the normal 46. His sex chromosomes are made up of two copies of the X chromosome and one copy of the Y chromosome, so his karyotype was 47,XXY, a karyotype consistent with Klinefelter syndrome.
Genetic analysis also revealed his paternal and maternal haplogroups* (genetic lineages traced on the basis of similar chromosomal mutations), revealing that the individual belonged through his father (Y-chromosome haplogroup) to a common European lineage in Western Europe, and through his father (Y-chromosome haplogroup). from his mother (mitochondrial haplogroup) to a rather rare European lineage, haplogroup V, found mainly in northern Iberia.
A man much taller than average.
For their part, the anthropologists proceeded to the morphological analysis of the remains of the individual to find out if it was compatible with the known symptoms of the genetic disease. The skeleton of the individual was “exceptionally well preserved“, they write. Which allowed them to determine that it was a man and that he was probably between 25 and 40 years old at the time of his death. His skeleton is immediately distinguished from the others by its imposing stature and the width of his pelvis With close At 1.80 meters, he far exceeded his congeners, because according to the bones found around him, the men of the time averaged less than 1.70 meters. The diameter of his hips was also larger than average, and his the teeth were worn, but asymmetrically, a sign of a probable malocclusion of the mandible, accompanied by maxillary prognathism.
Photographs of his skull show that he probably suffered from maxillary malocclusion and prognathism.. © João C. Teixeira et al. / the lancet
No signs of osteoporosis
According to the researchers, the results of this morphological examination are compatible with Klinefelter syndrome, because people with this genetic anomaly are generally tall, have wide hips and sparse hair. Other distinguishing signs: His testicles are relatively small and his mammary glands have developed (gynecomastia) due to androgen deficiency, also resulting in osteoporosis. Finally, they are often affected by a malformation of the jaw (prognathism), which causes more pronounced tooth wear. Most of these symptoms, in addition to osteoporosis, could be seen in the recovered skeleton. In fact, bone analyzes carried out at the Nuclear Medicine Department of the University Hospitals of Coimbra have shown that the bone mineral density values were completely normal in his femur. But that absence is not enough to invalidate the diagnosis, the researchers point out, because osteoporosis affects only 10% to 40% of identified cases of Klinefelter syndrome.
A new method to analyze degraded DNA
Since ancient DNA is very fragile and often degrades, the researchers preferred to be cautious before confirming their diagnosis. This is also the reason why they have developed a new statistical method”which is able to take into account the characteristics of ancient DNA as well as our observations“explain João C. Teixeira in a press release. In the archaeological context, the finding of the Torre Vieja man will allow researchers to better understand the incidence of Klinefelter syndrome and other genetic abnormalities in the past. But above all, once improved, the Bayesian method of fragmented DNA analysis can be used to diagnose other chromosomal abnormalities, such as trisomy 21 (Down syndrome), adds the geneticist, either in the context of forensic medicine, or even for prenatal diagnosis.