The so-called “Superman Syndrome” is not related to the superhero Superman; instead, it refers to a condition classified as chromosomal aneuploidy (an abnormality in the structure or number of chromosomes) where males have an additional Y chromosome (47, XYY syndrome).
DNA is passed down to us by our ancient ancestors, determining our appearance, how our bodies function, and even influencing our personalities. When all our genetic pieces are arranged correctly, we become a completely “normal” individual. However, there are times when even nature makes small mistakes, which can lead to catastrophic consequences.
The imperfections of nature can manifest as differences in the human body. You may have heard of chromosomal disorders such as Down syndrome. Such disorders occur due to some mishaps during cell division.
A rarely discussed chromosomal disorder is “Superman Syndrome” – Superman Syndrome. The chromosomal abnormality causing this syndrome is also known as Jacob’s syndrome. Estimates suggest that for every 1,000 male births, there is one individual with this syndrome.
So what exactly is “Superman Syndrome”? What causes it, and how does it affect an individual?
Sex Chromosomes
Before diving into the complexities of this chromosomal disorder, let’s review some basic genetics. All living organisms on Earth can be categorized into two groups based on the type of sex chromosomes they possess. Humans have 46 chromosomes in each cell. Among these 46 chromosomes, two—X and Y—determine an individual’s sex. A large portion of the human population has two sex chromosomes. Females have two X chromosomes, while males have one X and one Y chromosome.
In some rare cases, a zygote may have three sex chromosomes instead of two (XX or XY). One such abnormality is the male sex chromosome aneuploidy: Superman Syndrome.
In some cases, a zygote may have 3 sex chromosomes instead of 2.
What is Superman Syndrome?
The sex-determining cells in our bodies, sperm and eggs, undergo meiosis. If everything proceeds normally during the gamete cell division, we will have a normal individual with XX or XY chromosomes.
Superman Syndrome occurs when Y chromosomes fail to separate during spermatogenesis (the final stage of sperm formation), resulting in sperm that carries two Y chromosomes. Consequently, individuals with this condition (usually males) have an extra Y chromosome attached to their sex chromosomes: XY. This means they have 47 chromosomes in each cell and possess the sex chromosome composition XYY. Thus, Superman Syndrome in the medical community is officially referred to as 47, XYY syndrome.
In reality, this syndrome has been observed in approximately 1 in 1,000 male newborns. Although it is a common disorder, only about 20% of cases are reported. This is because symptoms such as tall stature or developmental delays are not distinct to this disorder, making it difficult to distinguish such individuals from the normal population.
Although the cause is a genetic defect, this condition is not hereditary. This is because the syndrome arises from an error occurring during sperm cell formation.
Superman Syndrome in the medical community is officially referred to as XYY syndrome.
How does it affect an individual?
Any abnormality in the body as significant as having an extra Y chromosome will certainly manifest itself in some way. If you add or subtract chromosomes, it will affect how the body develops and self-regulates.
One of the most common impacts is accelerated growth from childhood. XYY men have been found to be taller than normal males, with heights exceeding 1.85 meters.
Some XYY men exhibit reduced muscle tone, poor writing skills, and have permanent teeth that are longer and thicker, along with a higher risk of cardiovascular disease and kidney malformations.
Additionally, 47, XYY syndrome can weaken a person’s cognitive abilities. Boys with XYY syndrome may experience language learning deficits due to delays in speech development. Some find it difficult to remember words, understand symbolic and metaphorical language, and tend to exhibit attention-related issues similar to adult Attention Deficit Hyperactivity Disorder (ADHD).
It is believed that men with XYY syndrome may be infertile. However, science tells a different story. Many men with 47, XYY chromosomes have reproductive capabilities because the extra Y chromosome is often lost prior to cell division.
Why is it called “Superman” Syndrome?
Individuals with XYY are considered “super” males.
If you were hoping there was a profound scientific meaning behind naming a disorder after a famous fictional superhero, you may be disappointed.
Due to the presence of an extra Y chromosome, a characteristic chromosome of males, individuals with XYY are considered “super” males. Contrary to what you might expect from the name, a super male does not possess great powers to save us from villains like Lex Luthor.
While they are not superheroes, they are also not villains. It is worth noting that there is an unproven perspective that XYY men tend to be aggressive or have criminal inclinations. This is because some notorious criminals, such as John Farley and Daniel Hugon, have been found to have XYY chromosomes. However, reality has shown that both men and women with completely normal sex chromosome compositions are capable of committing the most heinous crimes.
