Moles, medically known as nevi, are common skin growths appearing as small spots that range in color from skin tone to brown or black. These growths form when melanocytes, the cells responsible for skin pigment, cluster together instead of spreading evenly across the skin. Most individuals develop between 10 and 40 moles by adulthood, typically appearing during childhood and the teenage years. While most moles are harmless, a central question for many concerns their potential to be passed down through families.
What Makes Moles Hereditary?
The number, types, and even location of moles an individual develops can have a genetic component. Specific genes are associated with an increased chance of developing moles; for instance, mutations in the CDKN2A gene are linked to familial atypical multiple mole-melanoma (FAMMM) syndrome, which involves numerous unusual moles and a heightened risk of melanoma. Another gene, BAP1, when mutated, has also been connected to an increased susceptibility to both moles and melanoma. These genetic variations can affect cell growth regulation in the skin, leading to mole formation.
Moles can be broadly categorized into common moles, atypical (dysplastic) moles, and congenital moles. Common moles are typically small and uniform. Atypical (dysplastic) moles, which tend to be hereditary, and congenital moles, present at birth, often show a stronger genetic influence.
Recognizing Hereditary Mole Patterns
Recognizing patterns that suggest a hereditary tendency for moles involves observing characteristics of your own moles and understanding your family’s medical history. One indicator is having a large number of moles; individuals with 50 or more moles may have an increased risk of melanoma. People with a very high number of dysplastic nevi, sometimes exceeding 100, might have dysplastic nevus syndrome, an inherited condition.
The presence of atypical moles is another important sign. These moles often appear larger than common moles, frequently exceeding 6 millimeters in diameter, and have irregular shapes. Their color can be uneven, showing shades of pink, red, tan, light brown, or dark brown, and their borders may be notched or fade into the surrounding skin. While a single atypical mole is usually benign, having multiple atypical moles increases the risk of melanoma.
Family history provides crucial information. If close relatives, such as parents, siblings, or children, have a history of numerous moles or melanoma, this suggests a hereditary component. FAMMM syndrome, for example, is a key indicator of such a predisposition. Understanding these patterns can help individuals identify if they might have a hereditary predisposition to moles.
Managing Moles with a Family History
Individuals with a family history of numerous moles or melanoma can take proactive steps to manage their skin health. Regular self-skin exams are important for monitoring existing moles and detecting any new growths. This involves systematically checking the entire skin surface, including areas not typically exposed to the sun.
When performing self-exams, it is important to observe moles for changes in asymmetry, border, color, diameter, and evolution (ABCDEs). Asymmetry means one half of the mole does not match the other. Irregular or notched borders, uneven color with multiple shades, and a diameter larger than 6 millimeters are also points to note. Any changes in a mole’s appearance over weeks or months, such as growth, itching, or bleeding, warrant attention.
Professional dermatological check-ups are highly recommended for those with a family history of moles or melanoma. A dermatologist can conduct a thorough skin examination, sometimes using a dermatoscope to view mole structures not visible to the naked eye. Baseline photographs of the entire skin surface can be taken to help track changes in moles over time. Sun protection, including seeking shade and using sunscreen, is a general preventative measure that helps reduce the risk of new moles and potential skin damage.