The emergence of white hair is both inevitable and natural. Several factors are implicated in accelerating this process, such as stress, sun exposure, and tobacco use. The role of our genes is also under scrutiny. Do we inherit the early onset of white hair from our parents? Here are some insights.
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Is white hair genetic?
Summary
Published June 1, 2023,
updated on May 28, 2024,
by
Pauline, Head of Scientific Communication
—
4 min read
Graying of hair: what is happening on our heads?
While the age at which the first gray hairs appear varies from person to person, everyone eventually notices a few white strands hidden in their hair. From a biological perspective, several mechanisms are at play. The graying of hair is primarily due to a decrease in activity and number of melanocytes, the cells that synthesize melanin. This melanin is then transferred to the keratinocytes, the cells surrounding the dermal papilla of the hair follicle. The distribution of melanin within the keratinocytes determines the color of the hair. In the absence of melanin in its cortex, the hair grows in white.
This is compounded by a gradual decrease in the rate of catalase in the cells of the scalp. Catalase is an enzyme that breaks down certain reactive oxygen species, such as hydrogen peroxide, before they trigger melanin destruction processes. Less catalase means less protection for hair pigmentation.
Genes involved in hair whitening?
Can the mechanisms described above be linked to genetics? Studies have delved into this question and the consensus is: gray hair is, at least in part, genetic. Among other findings, these studies have shown that individuals of so-called Caucasian type generally start to see their hair turn gray in their early thirties, those of so-called Asian type notice it in their late thirties, and those of so-called African type observe it during their forties.
Several genes have also been identified as being involved in the early onset of white hair, such as the MC1R gene (MelanocortinCortin 1 Receptor). Located on chromosome 16, it is a key gene in hair pigmentation. It codes for a membrane receptor protein primarily expressed in melanocytes. Indeed, when the α-melanocyte-stimulating hormone (α-MSH) binds to this receptor, it triggers a cascade of reactions within the cell, leading to the production of melanin.
A genetic mutation in the MC1R gene can influence the functionality of the receptor protein and thus the synthesis of melanin. This typically results in a light hair color, such as blonde, red, or light brown. In addition, certain alleles of the MC1R gene are associated with a higher risk of premature graying. Studies have shown that certain MC1R mutations are more frequently present in individuals with gray or white hair before the age of 30.
We can also consider the IRF4 gene, located on chromosome 6 and coding for a protein called Interferon Regulatory Factor 4. This factor plays a role in the regulation of transcription, which is the process that allows genetic information to be used to produce proteins.
Regarding hair pigmentation, the IRF4 gene is involved in regulating melanin production. Studies have shown that specific genetic variations of the IRF4 gene can influence when white hair appears. The exact mechanism by which the IRF4 gene influences hair whitening is not yet fully understood. However, it is suggested that the IRF4 gene could affect the differentiation and function of melanocytes, which would result in premature hair whitening.
Sources
RAWNSLEY J. & al. Hair biology: Growth and pigmentation. Facial Plastic Surgery Clinics of North America (2018).
ARUNKAJOHNSAK S. & al. A review of the etiologies, clinical characteristics, and treatment of canities. International Journal of Dermatology (2019).
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