20 Rare Genetic Features That You’re Unlikely To Have

You can blame genetics for all sorts of things: poor eyesight or flat feet, for example. But while these are common among humans, there are some genetic traits that are a little rarer. In fact, some are so rare that only a handful of people in the world share them. Indeed, from extraordinary blood types and heterochromia to extra ribs and even additional muscles, you probably don’t count these genetic attributes among those that you possess.

1. High bone density

Gene mutations aren’t always a bad thing. In fact, some of them can give you almost superhuman-like tendencies, such as the mutation of LRP5. Usually, it’s linked to low bone density, but scientists discovered it can also result in high bone density – in other words, near-unbreakable bones. The revelation came to light after a man suffered not a single fracture in a car crash in 1994, and physicians soon realized his extended family all carried the same trait.

2. Superhuman strength

Abnormal muscular strength in newborns is typically something you’d find in mice and cattle. But around the turn of the millennium, a mother gave birth to a baby in Berlin who carries the same genetic mutation, twice over. It turned out that both the boy’s myostatin genes are inactive. When that happens in animals, they grow up lean – and so too did the boy. According to a 2004 report in The New York Times, the mutation could lead to new cures for muscular dystrophy.

3. HIV defeater

More than 25 million people have lost their lives to HIV since 1981, but not everyone is equally susceptible to it. In fact, some people (primarily Europeans, especially those from the Baltic region) are actually immune, thanks to the gene mutation CCR5-delta 32, which essentially blocks the virus from entering cells. A single copy of the gene will only diminish the likelihood of getting infected, but the tiny portion of the population lucky enough to carry two will find themselves immune.

4. Color enhancer

Most humans are able to see millions of colors, but for a select few, that number is multiplied by a hundred. That’s thanks to the existence of a fourth cone in their retinas – one more than the usual three. Apparently, a whopping 12 percent of women carry this extra cone, but only a few are actually able to utilize it. Once again, it’s the result of a genetic mutation, and allows a person to see more colors than the rest of us will ever know.

5. Immunity to cholesterol

Back in 2004, scientists learned that a certain segment of the population is missing the PCSK9 gene. The result? An almost total immunity to high cholesterol. Yes, while missing genes is usually a cause for concern, people lacking this particular gene – and they’re everywhere, all over the world – needn’t worry about those heart conditions brought on by cholesterol. Naturally, drug companies are already working to find ways to suppress the gene in others, in order to lower their cholesterol levels.

6. Marfan syndrome

Not all genetic features affect your immune system, of course. Indeed, some are physical, such as Marfan syndrome. The hereditary disorder can literally alter your skeleton, resulting in fingers, arms and legs that may not be in proportion with the rest of your body. Other symptoms include bunched-up teeth, flat feet and severe nearsightedness. Marfan syndrome usually only gets worse as you get older and can even be life-threatening in some cases.

7. Live a longer life

It’s true: strong genes can help you live longer. In particular, the gene known as Serpine1, when mutated, added around an extra ten years to the lifespan of the members of an Amish community in Indiana who carried it, compared to those who didn’t. Scientists hope knowledge of the gene mutation will help to prevent diseases that come about with age, such as dementia.

8. Rh-null blood type

It’s no secret that some blood types are rarer than others. But then there are the really rare blood types, including one that’s only been found in a handful of people. Indeed, Rh-null blood has been described as “golden blood,” such is its scarcity – and its usefulness. It lacks every Rh antigen, making it a universal replacement for anyone who falls under the same blood-group system. So far, only 43 people in the entire world are known to have Rh-null blood.

9. Trimethylaminuria

Some genetic features aren’t quite as beneficial as golden blood, however. In fact, some are downright detrimental. Take trimethylaminuria, for instance, which is as unfortunate as its name is complex. Indeed, the disorder – which is caused by a faulty FMO3 gene – stops the body from processing trimethylamine. The chemical has a particularly strong smell, and as a result, the sufferer’s body odor is similarly pungent, reminiscent of garbage or decaying fish.

10. Preauricular sinus

Chances are, you’ve probably never met someone with a preauricular sinus. After all, it affects a tiny portion of the population – just 0.1 percent of people in the U.S., for instance. The disorder normally takes the form of a tiny hole at the top of the ear, a peculiarity caused during embryonic development. In fish, the hole would go on to become gills, leading some scientists to theorize that the condition could be an evolutionary relic.

11. Extra rib

Humans generally have 12 pairs of rib bones, but a select few can boast to having one more. It’s known as the cervical rib, and grows above the main rib cage, around the neck. For the most part, it’s harmless – unless it causes thoracic outlet syndrome, which can involve neck pain, loss of blood supply and may even stop you from being able to perform certain intricate hand and finger movements such as doing up buttons.

12. Hypertrichosis

It turns out werewolves aren’t solely the remit of horror movies. In fact, “werewolf syndrome” is a very real thing, even if the more politically correct term is hypertrichosis. It’s essentially abnormal hair growth all over the body, including the face, and is incredibly rare. Indeed, there are just 50 recorded cases of hypertrichosis going all the way back to the Middle Ages, and many of them are within the same families.

13. Distichiasis

Remember Elizabeth Taylor? The Cleopatra and Who’s Afraid of Virginia Woolf? actress was once considered the most beautiful woman in the world, and no doubt part of that was down to her astonishing eyelashes. That’s because Taylor was affected by distichiasis, a mutation of the FOCX2 gene that results in an additional row of eyelashes. Distichiasis can be harmless, but it can also result in eye irritation and even loss of vision, because the extra lashes grow so close to the eyeball.

14. Superathlete gene

Tibetans are well-used to high altitudes, but their ability to live at nearly 13,000 feet above sea level with no repercussions has baffled scientists for years – until 2014, when researchers discovered their secret. Indeed, it turns out their ancestors mated with an ancient, now-extinct species of human, the Denisovans, around 40,000 years ago. The result? A “superathlete” gene, EPAS1, passed down through the generations. The gene reduces the amount of hemoglobin in the blood, helping carriers to avoid strokes and blood clots.

15. Short sleeping

If you ever feel like you don’t need that much sleep to function, you may be what’s known as a “short sleeper.” Typically, these people can function on fewer than six hours of sleep per night. But don’t abandon your sleep schedule just yet – short sleep generally happens naturally. So if you force yourself to wake up every morning while really wishing you were back in bed, you’re probably not a short sleeper.

16. Treeman syndrome

There’s a reason why Epidermodysplasia verruciformis is also referred to as “treeman syndrome.” Indeed, the warts produced as a result of the genetic skin disorder bear a startling resemblance to flora. One of the most well-known cases was that of 34-year-old Dede Koswara from Indonesia, who appeared on the Discovery Channel and ABC, where he was referred to as “Half Man Half Tree” and “Tree Man.” The condition is brought on by a gene mutation, and while there’s no cure, the warts can at least be removed.

17. Heterochromia

Heterochromia is perhaps one of the more beautiful genetic features only a segment of the population possess. Typically, it’s present in the eyes, and results in them being different colors. While heterochromia can be picked up later in life through injury, it’s usually hereditary and is caused by a lack of genetic diversity in a person’s DNA. It’s also a genetic feature that’s not just limited to humans, but can apply in animals too, such as cats.

18. Ocular albinism

Not all eye conditions are so pleasant. Ocular albinism, for instance, can be debilitating for sufferers, as it severely impacts the pigmentation in your eyes. Essentially, it hampers your vision and can even result in issues with depth perception. Meanwhile, other symptoms can include strabismus, or eyes that focus in different directions, and photophobia – not a fear of photos, but rather a greater sensitivity to light sources. However, it doesn’t affect skin or hair color in the same way that regular albinism does.

19. Palmaris longus

Lay your hand palm-up on the table, then pinch your thumb and pinky finger together. If a tendon appears down the center of your wrist, then you have the palmaris longus. Don’t worry – it’s nothing to worry about. In fact, it’s simply an evolutionary hangover from our ancestors and these days serves little function in humans. In fact, it’s of most use to those species that still use their front limbs for mobility purposes, such as swinging through trees. It’s primarily beneficial to humans when used in tendon grafts.

20. Improved underwater vision

No matter how well you can see underwater, the kids of the Moken tribe in Thailand can do it better. In fact, a 1999 study by scientist Anna Gislen found that they could actually see twice as well as European kids beneath the surface. And while she discovered that this talent can be taught in other children, only the Moken youngsters were able to do so without suffering from irritation in the eyes – a genetic advantage, perhaps.