Are Lipomas Genetic? Causes and Hereditary Risk Factors
Learn how genetics and other risk factors contribute to lipomas and understand the distinction between a sporadic growth and a hereditary condition.
A lipoma is a common, slow-growing tumor composed of fat cells. These growths are almost always benign, meaning they are not cancerous. Many people discover them as soft lumps under the skin and question why they form, with a primary concern being whether they are inherited. While the exact cause is often unclear, genetics can play a part, particularly when an individual develops more than one.
Defining Lipomas
Lipomas are benign tumors of fat tissue that are soft, oval-shaped lumps just beneath the skin. They are encapsulated, meaning they do not spread into surrounding tissue, and feel rubbery to the touch. A defining characteristic is that they are movable under the skin with slight pressure. Most lipomas remain relatively small, often less than two inches in diameter, but can grow larger over time.
These growths can appear anywhere on the body but are most frequently found on the trunk, shoulders, back, abdomen, arms, and neck. While most people with a lipoma only have one, it is possible to develop several. They are common, affecting about 1 in 1,000 people, and appear during middle age, between 40 and 60 years old. Lipomas are generally painless but can cause discomfort if they grow near a joint or press on a nerve.
The Role of Genetics in Lipomas
While most single lipomas are sporadic, meaning they occur by chance without a known cause, genetics can be a factor. When multiple lipomas are present, there is a higher likelihood of a hereditary link. Certain genetic mutations are associated with lipoma development, particularly those involving rearrangements of chromosome 12. These alterations can disrupt the normal regulation of fat cell growth, leading to tumor formation.
Familial Multiple Lipomatosis (FML) is a rare inherited disorder that causes numerous lipomas. This condition is passed down in an autosomal dominant pattern, which means an individual only needs to inherit one copy of the mutated gene from a parent to be affected. The lipomas in FML often appear on the trunk and extremities and develop during adulthood.
Other genetic syndromes can also include lipomas as one of their features. Gardner syndrome, a disorder that causes various types of tumors, can lead to the formation of lipomas. Another condition is Bannayan-Riley-Ruvalcaba syndrome, a rare genetic disorder characterized by an enlarged head, other noncancerous tumors, and multiple lipomas. Madelung’s disease, more common in men with a history of excessive alcohol use, involves the growth of large, symmetrical fatty deposits around the neck and shoulders and also has a genetic component.
Other Factors Contributing to Lipomas
Genetics are not the sole contributor to lipoma formation, as other factors are associated with their development. Age is a factor, as they are more common in middle-aged individuals. The link between obesity and lipomas is sometimes discussed; while lipomas are made of fat, being overweight does not directly cause them but may increase the likelihood of their development.
Minor injuries are another potential trigger, with some research suggesting that trauma to an area can precede the formation of a lipoma, though this connection is debated. Certain medical conditions are also linked to a higher risk, including liver disease and glucose intolerance. Dercum’s disease, a rare disorder, is characterized by the growth of multiple, painful lipomas and is often accompanied by fatigue and weakness.
When to Suspect a Genetic Link
The most prominent indicator of an inherited condition is the presence of multiple lipomas. While a single lipoma is not usually genetic, developing several growths increases the chance of a hereditary cause like Familial Multiple Lipomatosis.
A strong family history is another clear signal. If close relatives have had multiple lipomas, there is a greater probability of a genetic predisposition. The age of onset can also be a clue, as lipomas appearing at an unusually young age may point toward a genetic syndrome. The pattern of the growths, such as the symmetrical deposits seen in Madelung’s disease, can also suggest an underlying genetic condition. If any of these indicators are present, consulting with a healthcare provider can help determine the cause.