Most of us have a birthmark somewhere on our skin, but this mom and daughter share one on their head. This DNA mutation is called Poliosis and results in the absence of melanin on any hairy part of the body. This unique birthmark can be inherited, or be caused by an autoimmune destruction of the pigment cells at the base of the hair.

Those are some pretty colored contacts right? Nope, this person has heterochromia iridis, a genetic variation that manifests in multicolored eyes. The duel coloring is caused by an excess or lack of melanin resulting from genetics, disease or an injury. The perfect split you see in the image below is called sectoral heterochromia and occurs when there are two different colors in the same iris. There is a dominant color and then a splash of second one.

This man's thumbs are there and just would not bend at the knuckle, but are fully formed and can be moved at the base of the fingers. Polydactyly runs in his family, too. Both him and his son had 12 fingers and 12 toes, although his boy had surgery when he was young.

Ulnar dimelia is a congenital deformity where the thumb is absent, the ulna is duplicated, and there are seven or eight fingers in the hand. The human body condition is often referred to as "mirror hand syndrome.” It is so rare that less than 100 cases have been reported in medical literature.

Wether we like it or not we are all a combination of the genes our parents gave us. Each gene is a blueprint for our bodies and the ones from our parents contain information that informs everything from eye color to diseases to the characteristics of our thumbs.

Anonychia congenita is a genetic condition that can affect the fingernails and toenails. People with this abnormality are usually missing all of their nails but in some cases (hyponychia) only some fingernails or a partial nails are missing. Those affected by anonychia congenita do not have any other health conditions as a result of their condition.

Stahl's ear (also called Spock's ear for all the Star Trek fans out there) is an ear deformity that results in a pointy ear shape as well as an extra cartilage fold. This abnormality is the result of a misshapen cartilage and when found in the first weeks of an infant's life ear molding is a viable treatment.

Born with Amniotic Band Syndrome, this person claimed they used to wrestle and since it was required that opponents shake hands before the first period, it was a great way to throw people off.

Symbrachydactyly is a condition where babies are born with an underdeveloped hand which causes them to have small, or in the case of the person below, missing fingers. Hand malformations are often treated with orthotics, prosthetics, physical therapy or in some cases surgery.

No this photo wasn't edited, that person really has a scar on their eye, or in medical terms - macular pucker. Macular pucker is a scar tissue that formed in the eye's macula which is located in the retina. This part of the eye gives the eye sharp vision, so this condition can cause blurred and distorted vision. Macular puckers occur when the vitreous of the eye ( a gel-like substance on its interior) pulls away from the retina.

This guy's rare freckle pattern may seem like it's a one-of-a-kind rarity but he's not alone. Back in 2015, California woman, Samantha, went on The Doctors to ask them to explain when she had a freckle pattern that sharply went along only one side of her body. The answer- a very specific type of birthmark. "It's a very specific type of birth mark which started when you were an embryo," dermatologist Dr. Sonia Batra told her. "And the pigment cells in your neural crest, some of them actually developed a mutation or a change and as the cells migrated over, it actually effects only half the body. 'That's why there's such a sharp cut off."

This may look like a cool haircut but your barber might have a tough time replicating it. A hair whorl is a patch of hair that grows in a circular clockwise or counterclockwise direction. This hair abnormality has been studied by behaviorists to see if their is a genetic link between handedness and whirl direction, but nothing absolutely conclusive has been found.

This is a perfect example of sectoral heterochromia, a difference in coloration of the iris when only part of it has a different color from its remainder. It may be inherited, or caused by genetic mosaicism, chimerism, disease, or injury.

When this person was 11, they woke up one morning to some of their eyelashes white. It happened overnight. Their mom thought they had bleached them somehow. It was only a very small section at first but it’s now over half of the eyelashes on this eye. It affects both top and bottom lashes, and they occasionally get one or two white hairs in their eyebrow. It’s a condition called Vitiligo and it occurs when your immune system is weak in a specific area, causing the color pigmentation to ‘drain’ out of the skin, or in their case, eyelashes.

Scientifically, this condition is known as syndactyly, but it's commonly referred to as webbed toes, even though it applies to both fingers and toes. Common in the animal kingdom, this condition is rarer among humans. Statistically there's one baby with webbed toes in 2000-2500 births. So syndactyly is not extremely rare and even Ashton Kutcher has it.

This case would require more scientific study. According to research as of now acquired characteristics are non-heritable characteristics of a living creature and that includes injuries and accidents. One possible explanation for this short index finger? a hand abnormality.

When you have a blonde streak or a white streak because of a localized decrease of melanin it's called poliosis. However, there is no certain name for when the area has increased melanin. Some people are calling this a "birthmark" and other's are saying it's probably just a discoloration in the hair and that it will eventually even out.

No this is not an elaborate Halloween prosthetic, these are what are called fimbriated folds of the tongue or plica frimbriata. The tentacle-like flaps occur when the folds that go alongside the frenulum (the tissue that connects the tongue to the bottom of the mouth) have small growths or skin tags on them. They are harmless but have the potential to get stuck in your teeth.

Often referred to as "double jointed" people who can move their joints beyond its normal range have what are called hypermobility. This is more common among children (10% to 15%) and usually decreases with age, as approximately 5% of adults have this ability. There are multiple causes of hypermobility including: altered bone shapes, stretched ligaments, muscle tone or stiffness and proprioception (sense of movement).

Six toes is a very common birth defect called Hexadactyly, which literally translates to six digits. This condition usually manifests as an extra finger or toe on the side of the toes or in between. Extra digits are usually harmless and can be removed easily but in other cases can be the side effect of a more serious condition.

Out of all the babies born 10% are born with malformations of the hand. These congenital defects occur early in pregnancy and are sometimes inherited or a symptom of another condition. The person in this photo has a cleft hand (also called ectrodactyly or split hand) which occurs when the middle part of the hand develops abnormally. Babies with this condition are born missing one or more central fingers on the hand. There are two types of cleft hands: typical (V-shaped and usually missing or partially missing middle fingers); and atypical (U-shaped and usually involves only one hand). 

The person in the photo above has all five functioning fingers except for one peculiarity - there's no thumb on the hand. This malformation is referred to as triphalangeal thumb where the thumb has three phalanges instead of two. It can be treated with reconstructive surgery by reshaping the finger so that it would operate like a thumb. It is estimated that approximately one in 25,000 children is born with the condition.

Nasal bridge is a saddle-shaped area that includes the nasal root and the lateral aspects of the nose. It appears that the person has a so-called depressed nasal bridge, which can occur due to various conditions. The most commonly encountered congenital syndromes with a depressed nasal bridge in the pediatric orthopaedic practice are cleidocranial dysplasia, children with neurodevelopmental delay, achondroplasia, Conradi-Hünermann-Happle syndrome, Cornelia de Lange syndrome, osteogenesis imperfecta and Klippel-Feil syndrome. Interestingly enough, this unique feature has its perks - the person who posted the photo said that his nose never bleeds.

Trigger finger is a condition that is found in one or more tendons of the hand. The tendon that allows the thumb to flex is too swollen and locks. Eventually the the thumb completely locks and is unable to bend at all. This condition is present in 3.3 per 1000 live births.

Bizarre birthmarks open the doors to myths, legends and folklore. In some cultures, it's believed that birthmarks represent your past life, in others - that gods have marked the baby as the chosen one to accomplish colossal deeds. In this case, as the parents of this baby joked, it's their first kid, so the number 2 might represent that the baby was supposed to have a twin, which she ate.

Pruney fingers occur when the nervous system sends a message to the blood vessels to become narrower. Scientists argue why our fingers tend to prune in water. It’s hypothesized that, as gatherers, it was easier to pick vegetation from wet environments and the wrinkling of our toes prevented us from slipping. So maybe this person has an ancestry with a greater expression of this trait.

What does it mean when your "little finger" is larger than the rest? Macrodactyly is a rare condition that causes an individual to have one or more fingers or toes that are much larger than the others. The exact cause is unknown but some believe is comes from an abnormal nerve or blood supply.

This picture is interesting even despite the internal bruising in the finger. After it was posted on reddit, a lot of people were asking why the hell they can't see any finger bones. It is because of how much the skin and flesh diffuse the light. Think of it as looking through a pane of frosted glass, times a thousand.

Polydactyly is the condition that causes a person to be born with extra digits on their feet or hands. Ryder was actually born with 12 fingers and 12 toes.