Blue hair is a unique and eye-catching hair color that has become increasingly popular in recent years. But what causes someone to have naturally blue hair? Is it something that can be inherited genetically or is blue hair always artificially colored? Here is a closer look at the genetics behind natural blue hair.
What Causes Blue Hair?
In most cases, blue hair is the result of artificial hair dyes and coloring processes. The human hair shaft contains the pigment melanin, which comes in two forms: eumelanin and pheomelanin. Eumelanin produces darker colors like black and brown, while pheomelanin produces lighter colors like blonde and red.
To achieve an unnatural shade like blue, the hair must first be bleached to remove the natural pigment. Then a blue dye or toner is applied to the bleached hair to deposit the cool, blue tones.
However, there are some rare genetic conditions that can produce natural blue hair in certain individuals. This blue color is the result of a structural abnormality in the hair shaft that causes it to refract light and appear blue. The two main genetic conditions associated with truly blue hair are:
- MCR1 gene mutation
- Pseudomonas infection
MCR1 Gene Mutation
The MCR1 gene provides instructions for making a protein called melanocortin 1 receptor. This is a receptor protein found on the surface of melanocytes, which are specialized skin and hair cells that produce melanin.
Certain mutations in the MCR1 gene can cause an alteration in melanin production, leading to an overload of pheomelanin pigment. This excess pheomelanin changes the way light is refracted off the hair, making it appear blue.
This genetic mutation is extremely rare. Only a handful of people worldwide have been observed to have blue hair due to an MCR1 mutation.
Pseudomonas Infection
Pseudomonas aeruginosa is a type of bacteria that can sometimes infect the hair follicles, especially if the skin barrier has been disrupted due to a cut or scrape. This bacterial infection interferes with melanin production in the hair shaft.
As the infection progresses, it destroys the normal pigment-producing cells in the follicles. Once the melanocytes are depleted, they can no longer produce melanin and the hair becomes clear. The transparent, colorless hair then refracts light and takes on a blue hue.
However, a Pseudomonas infection usually only affects a patch of hair rather than the whole head. So it typically results in a blue tuft of hair rather than all-over blue coloring.
Can Blue Hair Be Inherited?
For the most part, natural blue hair caused by genetic mutations is not directly inherited. The MCR1 mutations that lead to blue hair occur randomly and spontaneously. The Pseudomonas bacterial infection is also not an inherited condition.
However, in very rare cases, the mutated MCR1 gene has been observed to be passed down in families. There are a handful of reported families where multiple members have been born with blue hair due to the inherited gene mutation.
So while genetic blue hair does not follow the typical rules of inheritance, it can occasionally run in families. Babies born to parents who carry the mutated gene have a small chance of inheriting blue hair.
Prevalence of Blue Hair
True genetic blue hair is exceptionally rare. The prevalence has not been precisely determined due to how uncommon it is. However, it has been observed sporadically in a small number of individuals and families around the world. Some estimates suggest genetic blue hair occurs in as few as 1 in 1 million people.
By contrast, artificially colored blue hair has become quite popular in many urban areas and subcultures. While it is still an alternative style, up to 3% of people living in major cities have experimented with blue hair dye at some point.
| Type of Blue Hair | Prevalence |
|---|---|
| Genetic | 1 in 1 million |
| Dyed | Up to 3% in urban areas |
Genetic Disorders Linked to Blue Hair
There are a handful of genetic disorders and conditions that have been associated with blue hair in some cases. However, keep in mind these conditions do not always or necessarily cause blue hair.
Some examples include:
- Waardenburg syndrome – rare genetic condition characterized by hearing loss, pigmentation changes, and sometimes blue patches of hair.
- Methemoglobinemia – blood disorder that can cause bluish skin and occasionally bluish hair.
- Roberts syndrome – disorder causing slowed growth and sometimes blue-tinged hair.
- Biotinidase deficiency – inability to recycle biotin vitamin, sometimes linked to hair color changes like blue.
While these conditions have been occasionally associated with blue hair, the true genetic blue hair described earlier has only conclusively been linked to the MCR1 gene mutations.
Is the Blue Permanent?
For people with true genetic blue hair, the color is permanent. It will not fade or wash out over time, because the blue color stems from a permanent structural change in the hair strand itself. The mutated pigment genetics will continue producing blue hair throughout the person’s lifetime.
However, for artificially dyed blue hair, the color is temporary and will fade with washing. The hair will gradually return to its natural pigment over 4-8 weeks as the artificial dye washes away. To maintain a bold, blue color, the hair needs to be routinely re-dyed.
Conclusion
In summary, true genetic blue hair is extremely rare and caused by specific gene mutations that affect melanin pigment production. The most well-documented cause is an MCR1 mutation. While genetic blue hair can occasionally be inherited, most cases are spontaneous.
By contrast, artificially dyed blue hair is quite trendy and can be achieved by anyone with standard hair coloring products. However, this blue color will fade out over time as the dye washes away. So if you want to rock a head of blue hair, be prepared to put in some work maintaining it!
Genetic blue hair remains a fascinating and little understood phenomenon. With only a handful of documented cases, there is still much to learn about the genetics behind natural blue hair. It seems likely that additional genetic drivers will be discovered as more blue-haired individuals are studied and tested.
For now, blue hair remains an extremely unique trait. Anyone born with natural blue locks is part of a very exclusive club of extraordinary genetic rarities.
Blue hair, whether natural or dyed, is a bold way to express your individuality. But if you wake up one day with your hair suddenly turned blue, it may be wise to see a doctor and have your genetics tested. Chances are, though, that it is just a funky hair dye job rather than a genetic mutation.