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Are moles determined by genetics?
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Traits

Are moles determined by genetics?

While the tendency to develop moles appears to be inherited, the specific genetic factors involved are not fully understood.

Overview of Moles

Moles are common overgrowths of skin cells called melanocytes. While they are technically a type of cell overgrowth, they are almost always noncancerous (benign). Moles typically begin to appear in childhood and can change in size, shape, or color throughout a person's life. Factors such as hormonal changes (e.g., during pregnancy or adolescence) and sun exposure can influence their development.

Genetic Factors

Although the exact inheritance pattern is not well understood, the tendency to develop moles appears to run in families. Research has identified several genes involved in the development of benign moles:

  • BRAF Gene: This is the most-studied gene related to moles. A variant in BRAF produces an altered protein that causes melanocytes to aggregate into a mole. This protein also triggers the production of a tumor-suppressor protein called p15, which prevents the mole from growing too large.
  • Other Genes: Variations in genes such as FGFR3, PIK3CA, and HRAS are also associated with benign moles.

Moles and Cancer Risk

In rare cases, the interaction between genetic variants and environmental factors can lead to malignancy:

  • Malignant Transformation: If a BRAF gene variant is combined with the loss (deletion) of the CDKN2A gene, the body may fail to produce p15, potentially allowing mole cells to grow uncontrollably.
  • Sun Exposure: Ultraviolet radiation can damage existing moles. Individuals with fair skin, a family history of melanoma, or a high number of moles are at an increased risk.
  • Atypical Moles: Large, irregularly shaped moles known as dysplastic nevi are linked to heredity and can increase a person's risk of developing melanoma.

Because melanoma can develop in areas not exposed to the sun, researchers continue to study susceptibility genes to better understand the relationship between moles and skin cancer.

Frequently Asked Questions

Individuals with a strong family history of melanoma or those with dysplastic nevus syndrome should typically undergo a professional full-body skin examination at least once every 6 to 12 months. Dermatologists often use dermoscopy and sequential digital mole mapping to track subtle structural changes over time. Your specialist may recommend more frequent exams depending on your skin type, total mole count, and history of blistering sunburns.
mole can recur if some melanocyte cells remain in the deeper dermal layers after a superficial shave removal. Recurrent nevi often develop irregular pigmentation that can mimic melanoma under a microscope, a benign phenomenon known as pseudomelanoma. Complete surgical excision with full-thickness skin margins eliminates this risk. If a spot regrows after removal, have the clinician re-evaluate it to verify that the recurrence remains benign.
Clinicians recommend using the ABCDE criteria to monitor moles during monthly self-checks. Look for Asymmetry where one half does not match the other, Border irregularity with ragged or blurred edges, Color variations with multiple shades of tan, brown, black, red, or blue, Diameter larger than 6 millimeters (about the size of a pencil eraser), and Evolving changes in size, shape, elevation, or symptoms like itching and bleeding. Any mole that looks noticeably different from the rest of your moles, known as an ugly duckling sign, warrants prompt evaluation by a dermatologist.
While it is normal to develop new moles during childhood, adolescence, and pregnancy due to hormonal surges, the appearance of entirely new pigmented lesions after age 30 to 40 is less common and warrants clinical evaluation. Many new spots in older adults turn out to be harmless seborrheic keratoses or sunspots (lentigines), but a newly emerging mole in adulthood has a higher statistical likelihood of being an early melanoma compared to an existing mole that remains stable.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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