Many lymphatic malformations (LMs) and complex lymphatic anomalies (CLAs) are thought to be caused by changes in genes that affect how the lymphatic system develops. These changes are called pathogenic variants (previously known as mutations).
There are two main types of genetic variants that may be involved—somatic (mosaic) variants and germline (inherited) variants. Understanding the difference between them can help explain how a condition develops, why symptoms vary from person to person, and why most lymphatic conditions are not passed down in families.
Somatic (Mosaic) Variants
A somatic (mosaic) variant is a change in DNA that occurs after conception, while the baby is developing in the womb.
- The change affects some cells, but not all
- The body contains a mixture of typical cells and altered cells—this is called mosaicism
- Only certain tissues or areas of the body are affected
- Somatic variants are not present in egg or sperm cells
- They are not passed on to children
Most LMs and CLAs are believed to be caused by somatic (mosaic) variants.
Germline (Inherited) Variants
A germline variant is a change in DNA that occurs in a reproductive cell (egg or sperm) and becomes part of every cell in the child’s body.
- These variants may be inherited from a parent
- They can be passed down to future generations
- The genetic change is present throughout the body, not limited to one area
Most individuals with lymphatic conditions—even those with complex or early-onset symptoms—do not have an inherited genetic cause.
