A cleft chin, more famously known as a “butt chin,” is characterized by a dimple or crease in front of the chin. While it is a seemingly harmless trait, it can become pesky at times. From being a tough shaving spot to its increasingly prominent display on your portrait, it can cause minor inconveniences. But did you know that in some places, a cleft chin is considered a beauty trait? Whether you have chosen to embrace it or trying ways to get rid of it, understanding the genetics and inheritance of cleft chin can come in handy.
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What Is A Cleft Chin?
A chin with a Y-shaped dimple in the middle is a cleft chin. It is a genetic trait.
People with less facial fat will have a more noticeable cleft or dimple on the chin. Cleft chin has had cultural significance in some communities around the world.
In ancient China, a cleft chin was associated with royalty.
This feature is most noticeable when the mouth is closed and the jaw is at rest.
The appearance of a cleft chin can vary in depth and size among different individuals.
Having a cleft chin is a normal variation in human anatomy and is neither a health concern nor a sign of any underlying medical condition.
It's simply a trait that can be inherited, much like eye color or hair type.
How Does A Cleft Chin Develop?
Cleft chins are a result of an unfused jawbone.
The shape of your chin is determined even before you are born.
As the fetus develops, the mandible or the jawbone grows from both sides of the head and meets in the middle of the chin.
In some people, the bones don’t fuse, leaving a small gap or cleft.
The skin over the tiny gap is indented, creating the dimple.
Is A Cleft Chin The Same As A Chin Dimple?
A cleft chin is the same as a chin dimple.
It is also colloquially referred to as “butt chin.”
What Causes Cleft Chin?
Like our other facial features like eye color, nose shape, etc., a cleft chin is also a strong trait of genetics.
A cleft chin is caused due to mainly two reasons:
- The lower jawbone did not wholly fuse during fetal development. It could have been a natural occurrence or due to an injury to the mother or the fetus.
- Because of the excessively spaced chin muscles, the skin on the chin did not connect to create a normal round chin.
Cleft Chin Genetics
A cleft chin is inherited as a dominant trait.
You will receive two copies of a gene at birth from either of your parents.
If one copy is that of a cleft chin, you will likely have one.
However, you might sometimes have a cleft chin even though neither of your parents has it.
Is Cleft Chin Dominant Or Recessive?
A cleft chin is a dominant trait.
A dominant trait means that if you have one copy of the cleft chin gene from one parent, you will likely have a cleft chin.
However, this theory is contested.
Sometimes, you can have a cleft chin even though neither of your parents has it.
This phenomenon is called “genetic penetrance,” a common genetic trait where genes skip a few generations before they appear again.
How’s Cleft Chin Inherited?
Since it is a dominant condition, theoretically, even if one biological parent has a cleft chin, there’s a 50% chance that you will also have it.
What Gene Causes Cleft Chin
Genes that control tongue development also control chin development.
Tongue and jaw genes are also linked to the roof of your mouth and have a role in cleft palates and lips.
The genetic marker for cleft chin is located in chromosome 2, called rs11684042.
Sex-linked Differences
Cleft chins can appear differently in males and females due to hormonal influences and differences in bone structure. Generally, it might be more pronounced in males.
Not Entirely Genetic
While genetics play a crucial role in the development of a cleft chin, environmental factors during fetal development can also influence its appearance.
Cleft Chin Genetics: Is There A Test?
Cleft chin is not something that one can "develop" as they age.
Therefore, a genetic test to understand the likelihood of developing a cleft chin would be pointless.
However, if you are curious about this trait, companies like 23andMe offer a test where they analyze 38 variants for cleft chin.
Even if you do not have a cleft chin, you may contain variants associated with them, which may express themselves in future generations through the previously seen concept called penetration.
A cleft chin genetic test could be a fun way to understand your "hidden traits."
Summary: Cleft Chin Genetics
The cleft chin is a Y-shaped dimple on the chin.
It usually happens when the two parts of the jaw bone do not fuse properly, which creates a gap or cleft.
Like many other traits, such as eye color or height, cleft chin also has a genetic basis.
It is hereditary, which means you are likely to have it if your parents have it.
No specific tests identify a gene associated with a cleft chin.
References
https://udel.edu/~mcdonald/mythcleftchin.html
https://www.healthline.com/health/cleft-chin
