Last Saturday the British television channel Channel 4 showed the first part of the documentary entitled Hitler’s DNA: the model of a dictatorwhich chronicles a research group’s recent efforts to sequence Hitler’s genome from a piece of blood-stained tissue, believed to have come from the sofa where he committed suicide on April 30, 1945. One of the authors is British geneticist Turi King, who is credited with identifying the remains of England’s King Richard III in 2013.
There was a lot of discussion about this because the results of research presented in scientific journals but not yet published, made it possible to formulate several hypotheses, more or less solid but of great interest to the media, about Hitler’s health. One of them is that he suffers from Kallmann syndrome, a genetic disease that causes imperfect sexual development. Another thing, much more dubious, is that he had a special predisposition to attention deficit hyperactivity disorder, and other mental disorders.
The discussion focuses on the reliability of the results, but also on the meaning and risks of carrying out this kind of research on prominent figures in history: even more so in the case of figures who are notoriously violent and violent.
On the one hand, similar research could theoretically contribute to making these characters more three-dimensional, providing a contextual element that is useful from a historiographic point of view. But on the other hand, there is a risk that already very uncertain data will be used to determine the correlation between certain genetic traits and the alleged talents of the human beings in question. The risk, in particular, is that the research implicitly reinforces the idea that negative or even lethal choices and actions depend more on heritable and predictable genetic factors than on being influenced by variable and unpredictable environmental factors.
Portrait of Adolf Hitler as a child, undated (Bettmann/Getty Images)
To prove the authenticity of the blood on the cloth stored at the military history museum in Gettysburg, Pennsylvania, the research team first requested DNA samples from Hitler’s living relatives, who refused to cooperate because of the risk of media attention. Ultimately the group supported the authenticity of the find by comparing it with a blood sample from an alleged relative of Hitler’s, collected in the early 2000s by a Belgian journalist (however, it is unclear how the group came into possession of the sample).
The first conclusions drawn by the research group made it possible to debunk the well-known conspiracy theory – long supported, among others, by Russian Foreign Minister Sergei Lavrov – according to which Hitler was of Jewish origin and that his father was born from an extramarital affair. But according to the group, the hypothesis that he suffered from Kallmann syndrome, which can affect puberty, sexual organ development and libido, is reasonable. This is proven by analysis of a gene called PROK2, the results of which also match documents known to come from a medical examination carried out on Hitler in 1923, which reported a diagnosis of cryptorchidism (failure of one or both testicles to descend into the scrotum).
If the documentary limited itself to these conclusions, it would be sensational but overall believable, he commented Guardian. The problem is that the authors also wanted to evaluate Hitler’s genetic predisposition to psychiatric and neurological pathologies through a so-called polygenic risk test, from which emerged a “high” to “above average” probability of developing attention-deficit hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder.
This is the most talked about and scientifically weakest part of the entire study. Polygenic risk tests are used to develop a rough estimate of the risk of developing certain multifactorial diseases, i.e. caused by many factors. These are diseases – mostly neurodegenerative, metabolic, and cardiovascular – that depend not only on genetics, but also on environment, habits, behavior, and chance. In general, its predictive value is highly questionable also because the comparative data used to develop estimates come from a limited and not sufficiently heterogeneous population sample.
One risk reported by some scientists not involved in the research is that documentaries such as those about Hitler’s DNA may support an approach based on genetic determinism and not be supported by valid scientific evidence. “Polygenic risk scores provide information about the population at large, not individuals,” he said Guardian David Curtis, professor at the Institute of Genetics at University College London.
Even if tests show a certain predisposition, Curtis explains, “the actual risk of developing the condition may still be very low, even for conditions that are heavily influenced by genetic factors.” And in the case of mental disorders such as attention deficit hyperactivity disorder, according to many scientists, the predictive value of polygenic tests is lower than that of psychological tests.
In general, particularly in the case of autism and attention-deficit hyperactivity disorder, associating these conditions with figures universally considered to be the personification of evil risks increasing stigma. Or vice versa, there is a risk of creating an attitude of empathy and understanding of individual behavior whose relationship to the disorder may be unfounded and non-existent.
