Did you know ? 47,XYY syndrome is the killer syndrome

Genetics surely still hides mysteries for you. Indeed, did you know that some individuals are affected by an astonishing syndrome characterized by an abnormal presence of a second Y chromosome: this is the 47,XYY syndrome, also called Jacob’s syndrome or killer syndrome.

The 47,XYY killer syndrome is not at first sight characterized by specific physical traits. Indeed, the person who wears it has no unusual physical features or medical problems. The anomaly is then only identified with the help of genetic analyses, often carried out within the framework of other fields.

However, children with this syndrome have on average more learning problems, ie 50% higher, and some delay in language development. In a study carried out in 2004 in the United States by the Centers for Disease Control and Prevention, researchers found that 10% of affected children had learning problems. Some developmental delays or behavioral issues have also been noted, but these vary by individual. They would also tend to be more aggressive. Moreover, 47,XYY syndrome is not an inherited disease and can appear in any individual during the formation of their cells.

The debate on a person’s genetic predisposition to becoming a criminal has regularly been revived, notably in October 2014 when a study was published in the specialized journal Molecular Psychiatry. This highlighted two specific genes found “with a significantly higher frequency among violent offenders”. Nevertheless, some scientists warn about these genetic predispositions to violence. “Talking about violence genes would be a huge exaggeration.”, explains in particular Jan Schnupp, professor of the department of neurosciences of the university of Oxford. Indeed, both versions of these mutated genes”are quite common in the population”. One in five people wear them and many of them won’t commit a crime. The study also presents cases of unaffected people who still committed violent acts. The debate on an individual’s genetic predisposition to become a criminal therefore remains open and controversial.

This criminal’s chromosome has also inspired fiction on several occasions. Indeed, during the 1960s and 1970s, false rumors suggested that men with the XYY karyotype tended to engage in criminal behavior. Ideas then taken up in several novels or series, such as Doomwatch (1970-1972) by Robin Chapman and broadcast on the BBC which recounts in one of the episodes the dramatic consequences of these rumours. Another example: in the film Alien 3, the main character finds himself in a prison-like planet that is inhabited entirely by criminals with the XYY karyotype, with the idea that they are more likely to commit crimes and rape. Finally, in the series of games Hitmanthe hitman ” Ultimate code 47 is so called because its creator managed to understand the mysteries hidden behind chromosome 47.