The condition known as Hereditary Leiomyomatosis And Renal Cell Cancer is a rare disorder that causes benign tumors to form. These fibroid tumors are concentrated in smooth muscle tissues (technically known as leiomyomas) just beneath the skin.
Female sufferers also experience fibroid tumor growths in the uterus. Complications which occur along with the condition include higher risks of developing cancer in the kidneys. In the interest of brevity this condition is usually called “HLRCC.”
HLRCC sufferers typically see the first growths (called cutaneous leiomyomas) appear on the skin after age 30. Initial growths are small, affecting the minuscule muscles that are responsible for raising “goose bumps.” The growths manifest themselves as nodules which show up on the torso, legs, and arms. Growths on the face are rare but not unheard of.
The coloration of the growths may match the surrounding skin or be somewhat darker. Over time the number and size of growths tends to increase. Many patients find them extremely sensitive, especially to cold, and they are often painful.
Females who have HLRCC can encounter leiomyomas developing in the uterus, commonly called fibroids. This is not the only condition which can cause fibroids, but those associated with HLRCC typically appear earlier and in greater numbers and size than those with other origins.
10 to 16 percent of HLRCC sufferers also find themselves afflicted with renal cell cancer, a significant kidney problem. Renal cell cancer causes several symptoms of varying severity. These can include passing blood and experiencing pain in the lower back. In some patients physical examination can reveal the presence of an anomalous mass in one or both kidneys.
Renal cell cancer may pass unnoticed until the condition reaches a very advanced stage. The kidney-related complications of HLRCC typically manifest about 10 years after the appearance of growths on the skin.
Alternative names for the condition include multiple cutaneous and uterine leiomyomatosis (MCUL) or multiple cutaneous leiomyomatosis (MCL). Doctors typically only apply these terms in cases where there is no renal cell cancer.
How Many People Have HLRCC?
This is an exceptionally rare condition. Fewer than 100 families in total have been diagnosed with HLRCC globally. The number of undiagnosed cases has not been estimated.
Is HLRCC Genetic?
Due to its rate of recurrence among family members, a genetic component to HLRCC was strongly suspected. This has been confirmed by the discovery of a link between HLRCC and a mutated FH gene. This gene is named for its role in regulating the production of fumarate hydratase (or fumarase), a key component in the citric acid cycle. This process enables the absorption of oxygen and the generation of energy on a cellular level. Fumarase is responsible for creating malate out of fumarate.
Individuals who are diagnosed with HLRCC have a single mutated FH gene present in their DNA. While the copy of the gene from the person’s other parent starts off healthy, it too can suffer mutation due to UV radiation exposure (from the sun) or DNA replication errors.
Too many mutated FH genes may disrupt the citric acid cycle and cause excess fumarate to build up. This in turn could make it difficult to properly regulate the amount of oxygen in individual cells. In cells where both copies of the FH gene are defective, the result may be hypoxia (oxygen deficiency) and tumor formation.
How Is HLRCC Transmitted?
As its name suggests, HLRCC is an inherited condition. A single copy of the mutated gene is enough to cause HLRCC, making it autosomal dominant. Most HLRCC cases can be linked to inherited genes, but a few examples indicate that the condition can also arise independent of inheritance thanks to post-natal mutation.