Hair loss is a common problem that affects millions of men and women around the world. While genetics is believed to be the most significant factor contributing to hair loss, other factors can also play a role, including stress, hormonal changes, and certain medications. In this article, we will explore the genetics of hair loss, including the genes that are involved, the inheritance patterns, and the impact of genetics on hair loss, as well as other factors that can contribute to hair loss.
Contents
Types of hair loss
Hair loss can occur in different ways and can be classified into different types, including:
- Androgenetic alopecia: Androgenetic alopecia, also known as male or female pattern baldness, is a common form of hair loss that is primarily caused by genetics [1]. The condition is caused by a sensitivity to the hormone dihydrotestosterone (DHT), which causes hair follicles to shrink and eventually stop producing new hair. The likelihood of developing androgenetic alopecia is largely determined by genetics, with several genes involved in the development of the condition.
- Hair structure genes: The structure of an individual’s hair is also influenced by genetics [2]. Hair texture, thickness, and growth rate are all determined by the genes that control hair production. Differences in these genes can result in hair that is more susceptible to damage and breakage, leading to hair loss.
- Alopecia areata: This type of hair loss occurs when the immune system attacks the hair follicles, leading to hair loss in patches. It can affect people of all ages, and it can be triggered by stress or certain medications. [3]
- Telogen Effluvium: Telogen effluvium is a condition in which hair falls out suddenly and in large amounts, often as a result of stress, hormonal changes, or medications [4]. The genetics of telogen effluvium is not well understood, but researchers believe that certain genes may play a role in an individual’s susceptibility to the condition.
Baldness gene and other hair loss genes
Hair loss is a complex trait that is influenced by many genes. While the androgen receptor gene (AR), often referred to as the baldness gene, is one of the most well-known genes associated with hair loss, many other genes can also play a role [2]. For example, the 20p11 gene is involved in the production of a protein called prostaglandin D2 (PGD2), which has been shown to inhibit hair growth [5]. Variations in the 20p11 gene can lead to increased production of PGD2, which can contribute to hair loss.
Additionally, researchers have recently identified a gene called the FOXC1 gene, which is involved in the regulation of hair follicle development [6]. Variations in this gene can lead to a decrease in the number of hair follicles, which can contribute to hair loss.
Another gene that has been linked to hair loss is the LSS gene [7]. This gene is involved in the production of a protein called lanosterol, which has been shown to promote hair growth. Variations in the LSS gene can lead to decreased production of lanosterol, which can contribute to hair loss.
Is hair loss hereditary? How much is influenced by genetics?
Yes, hair loss can be hereditary [2]. The extent to which genetics influences hair loss can vary, but it is estimated that up to 80% of cases of androgenetic alopecia (the most common form of hereditary hair loss) are due to genetic factors. Additionally, hair structure genes play a significant role in determining the size, shape, and texture of hair, and mutations in these genes can cause hair loss or other hair disorders. However, it’s important to note that genetics is just one of several factors that can influence hair loss and that lifestyle, environment, and other factors can also play a role.
Inheritance patterns of hair loss
The inheritance patterns of hair loss are complex and can vary depending on the specific type of hair loss. The most common type of hair loss, androgenetic alopecia, is inherited in a polygenic pattern, which means that it is caused by multiple genes, each of which has a small effect on the trait. This type of hair loss is also influenced by environmental factors, such as stress and nutrition [8].
Some rare forms of hair loss are inherited in a Mendelian pattern, which means that they are caused by mutations in a single gene. For example, alopecia areata is an autoimmune disorder that can be inherited in an autosomal dominant pattern [9].
Other forms of hair loss, such as frontal fibrosing alopecia and lichen planopilaris, have been linked to specific genetic variations, but their inheritance patterns are not yet well understood [10, 11].
Male vs female pattern baldness
Male and female pattern baldness differ in the pattern and degree of hair loss [12]. Male pattern baldness typically starts with a receding hairline and thinning at the crown of the head, while female pattern baldness usually involves thinning throughout the scalp, with the hairline remaining intact. Scientific studies have identified several genes associated with male pattern baldness, including the androgen receptor gene and the aromatase gene, which are involved in testosterone and estrogen metabolism. Female pattern baldness, on the other hand, is less well understood, but it is thought to involve a complex interplay of genetic and hormonal factors. Further research is needed to fully understand the underlying causes of male and female pattern baldness and to develop effective treatments.
Causes of hair loss
While genetics is a significant factor in hair loss, other factors can also contribute to the condition. For example, stress, diet, and medication can all play a role in hair loss. Additionally, not all cases of hair loss are genetic. In some cases, hair loss may be due to an underlying medical condition or a side effect of medication [13].
Stress is a significant factor in hair loss. When the body is under stress, it produces the hormone cortisol, which can contribute to hair loss by damaging hair follicles. In addition, poor nutrition can also contribute to hair loss. A diet that is low in protein, iron, and other essential nutrients can lead to thinning and hair loss.
Certain medications can also contribute to hair loss. For example, chemotherapy drugs can cause hair loss by damaging hair follicles, and some medications used to treat high blood pressure and depression can also contribute to hair loss.
Despite these factors, understanding the genetics of hair loss can help develop new treatments for the condition. Researchers are currently exploring ways to target the genes and proteins involved in hair loss, to develop more effective treatments that can slow or even reverse the process.
Preventing hair loss
While some types of hair loss cannot be prevented, some measures can be taken to reduce the risk of hair loss, including [14]:
- Eating a healthy diet that is rich in vitamins and minerals
- Managing stress through relaxation techniques such as meditation and yoga
- Avoiding hairstyles that pull on the hair, such as tight braids and ponytails
- Treating any underlying medical conditions that can cause hair loss, such as thyroid disorders and autoimmune diseases
If you notice that you are experiencing hair loss, you should see a doctor to determine the cause and discuss appropriate treatment options. With the right treatment and care, it is possible to slow down or even reverse the progression of hair loss and restore your confidence and self-esteem.
Treatment options for hair loss
There are several treatment options available for hair loss, including medications, hair transplant surgery, and scalp micro-pigmentation [15].
Medications such as minoxidil and finasteride are commonly used to treat hair loss [16]. Minoxidil is a topical solution that is applied to the scalp, and it works by increasing blood flow to the hair follicles, which can stimulate hair growth. Finasteride is a medication that is taken orally, and it works by blocking the production of the hormone DHT, which can cause hair follicles to shrink and stop producing hair.
Hair transplant surgery is another option for treating hair loss [17]. This procedure involves taking hair follicles from a donor area, typically the back of the head, and transplanting them to the bald or thinning areas of the scalp. Hair transplant surgery can be a highly effective treatment for hair loss, but it is also expensive and can be associated with complications such as infection and scarring.
Scalp micro-pigmentation is a non-surgical treatment option for hair loss that involves tattooing the scalp to create the appearance of a buzz cut or short hair. This treatment can be an effective way to conceal hair loss, but it is not a permanent solution, and it may need to be repeated every few years.
Conclusion
Hair loss is a common condition that can be caused by a combination of genetic and environmental factors. While genetics is a significant factor in hair loss, other factors such as stress, diet, and medication can also contribute to the condition. By continuing to study the genetics of hair loss and other factors that can contribute to the condition, we may be able to develop more effective treatments for this common condition in the future.
In conclusion, it is important to understand the complex nature of hair loss and the many factors that can contribute to the condition. By taking a holistic approach to treatment, including addressing genetic, environmental, and lifestyle factors, we can help to slow, prevent or even reverse hair loss.
References
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[5] Liang B et al. Genetic variants at 20p11 confer risk to androgenetic alopecia in the Chinese Han population. PLoS One. 2013 Aug 26;8(8):e71771. doi: 10.1371/journal.pone.0071771. PMID: 23990985; PMCID: PMC3753324. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0071771
[6] Zhou LB, Cao Q, Ding Q, Sun WL, Li ZY, Zhao M, Lin XW, Zhou GP, Fan WX. Transcription factor FOXC1 positively regulates SFRP1 expression in androgenetic alopecia. Exp Cell Res. 2021 Jul 1;404(1):112618. doi: 10.1016/j.yexcr.2021.112618. Epub 2021 May 7. PMID: 33965401. https://www.sciencedirect.com/science/article/abs/pii/S0014482721001506
[7] Romano MT et al. Bi-allelic Mutations in LSS, Encoding Lanosterol Synthase, Cause Autosomal-Recessive Hypotrichosis Simplex. Am J Hum Genet. 2018 Nov 1;103(5):777-785. doi: 10.1016/j.ajhg.2018.09.011. Epub 2018 Oct 25. PMID: 30401459; PMCID: PMC6218848. https://www.cell.com/ajhg/fulltext/S0002-9297(18)30322-7
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[10] Retrieved 28 April 2023 from https://www.aad.org/public/diseases/hair-loss/types/frontal-fibrosing-alopecia
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