SNP Shot: Genomic Insights

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a genetic condition characterized by the development of non-cancerous tumors called leiomyomas. These tumors, composed of smooth muscle tissue, typically appear on the skin and, in women, in the uterus. Additionally, HLRCC increases the risk of developing kidney cancer.

Skin growths (cutaneous leiomyomas) are common in HLRCC, often appearing around the age of 30. These growths typically originate from the small muscles associated with hair follicles, responsible for "goosebumps." They manifest as bumps or nodules on the torso, arms, legs, and occasionally the face. These skin leiomyomas can be the same color as the surrounding skin or appear darker. While some individuals may have few or no cutaneous leiomyomas, the growths tend to increase in size and number over time. They are often more sensitive to cold or light touch and can be painful.

Uterine leiomyomas (fibroids) are also common in women with HLRCC. While uterine fibroids are prevalent in the general female population, women with HLRCC tend to develop numerous, large fibroids at a younger age compared to the general population.

Approximately 10% to 16% of individuals with HLRCC will develop renal cell cancer, a type of kidney cancer. Symptoms of renal cell cancer may include lower back pain, blood in the urine, or a palpable mass in the kidney. However, some individuals may not experience any symptoms until the cancer has progressed. Individuals with HLRCC are often diagnosed with kidney cancer in their 40s.

When this disorder is present in individuals or families without a history of renal cell cancer, it's sometimes referred to as multiple cutaneous leiomyomatosis (MCL) or multiple cutaneous and uterine leiomyomatosis (MCUL).

Inheritance:

HLRCC follows an autosomal dominant inheritance pattern. This means that inheriting only one copy of the mutated gene from either parent is sufficient to cause the condition. Sometimes, a person inherits the altered gene from a parent who also has HLRCC. In other instances, the condition arises from a new gene mutation in an individual with no family history of HLRCC. Children who inherit two mutated copies of the FH gene (one from each parent) develop a different, often fatal condition called fumarase deficiency. While people with HLRCC are potential carriers of fumarase deficiency as they can pass on one mutated copy of the gene to their children, they do not exhibit signs or symptoms of fumarase deficiency themselves.