(Washington) Almost two centuries ago, on March 26, 1827, one of the most influential composers of classical music, Ludwig van Beethoven, died in Vienna at the age of 56. But since then, the debates around the exact reasons for his death have never ceased between specialists.

Researchers have now used a novel technique to shed new light on the German composer’s untimely demise: by analyzing his DNA from strands of his hair.

Their study, published Wednesday in the scientific journal Current Biology, revealed strong genetic predispositions to liver disease, as well as hepatitis B virus infection late in life, two factors that likely contributed to his death. , most certainly cirrhosis, aggravated by alcohol consumption.

But unfortunately they could not explain the cause of his progressive deafness, which caused so much pain to the author of the 9th Symphony.

In 1802, the composer had expressed his desire, in a letter to his brothers written in a moment of despair, that his illness be described after his death and made public.

“We sought to fulfill that wish,” said Tristan Begg, a researcher at the University of Cambridge and lead author of the study, at a press conference.

And while the mystery still lingers around some of the many pathologies Beethoven suffered from, “we were extremely lucky […] to achieve such fascinating results,” said Mr. Begg, the originator of this project, which started in 2014.

Until now, research on Beethoven’s health has mainly come from his correspondence, his diary, notes from his doctors, or even an autopsy report.

This time, the scientists looked at eight locks of hair presented as belonging to Beethoven, and from public or private collections.

They determined that five of them were from a single male individual, with alterations showing that they dated back to the early 19th century.

Among these five locks, the history of transmission for two centuries is uninterrupted for two of them, and supported by rich documentation. One was given in 1826 by Beethoven himself to a musician friend, and the second was from a family friend who arranged his funeral – until being auctioned off in 2016.

These five locks, which cover the last seven years of Beethoven’s life, are almost certain to be authentic, according to the researchers.

Three others, on the other hand, were disqualified, including one that had been used to support the hypothesis of death by lead poisoning, but in fact belonged to a woman.

The DNA sequencing then took place in Germany, in the laboratory of the Max-Plank Institute for Anthropology in Leipzig, where prehistoric men are usually studied instead.

Unlike bone analysis, “in the hair, the DNA is very degraded,” said Johannes Krause, head of the institute’s genetics department and co-author of the study. “It was difficult to harvest enough DNA to assemble the genome. »

Several meters of hair were used, and finally, three quarters of the genome (all the genes of a living being) could be mapped.

Beethoven, who had at least two bouts of jaundice, the first of which in 1821, had “a considerable genetic predisposition” to liver disease, the study concludes.

It also reveals that Beethoven had an infection with the hepatitis B virus, at least during the last months of his life, but which could have been earlier. A chronic infection is one of the major causes of cirrhosis.

We also know that Beethoven was a heavy drinker.

“So we believe that his disease stems from an interaction” between these three factors, explained Markus Nöthen, also a co-author of the study.

On the other hand, the researchers could not issue a definitive conclusion for the composer’s intestinal problems (but lactose intolerance is excluded), nor especially for his deafness, which could have been caused by otosclerosis or Paget’s disease. .

To conclude their work, the scientists compared Beethoven’s DNA with that of five Belgian men who shared with the composer a distant relative who lived in the 16th century, Aert van Beethoven.

Surprise: the Y chromosome of these five men does not match that of the musician.

According to the researchers, the only possible explanation is an extramarital affair, somewhere between the seven generations separating this common ancestor and the birth of Beethoven, in Bonn in 1770.

“You cannot exclude that Beethoven himself is illegitimate,” Tristan Begg said. ” It’s a possibility. »