CYLD cutaneous syndrome
CYLD cutaneous syndrome is a genetic condition characterized by the growth of multiple benign skin tumors and an increased risk of developing other types of tumors.
Overview
CYLD cutaneous syndrome involves the growth of multiple noncancerous (benign) skin tumors that develop from skin appendages. Common tumor types include:
- Cylindromas: Often appear on the scalp; believed to begin in hair follicles.
- Spiradenomas: Often found in conjunction with cylindromas.
- Trichoepitheliomas: Typically develop on the skin around the nose and upper lip.
While usually benign, these tumors can occasionally become cancerous (malignant), grow rapidly, and form ulcers. Tumors may also develop in other structures, such as the salivary glands.
Clinical Progression
Tumors typically begin to develop in late childhood or the teens. They tend to increase in size and number over time. Large tumors can become infected or cause sensory issues if they occur near the eyes, ears, nose, or mouth. In rare cases, cylindromas in the lungs can cause breathing difficulties.
Causes
The condition is caused by mutations in the CYLD gene, which produces an enzyme that acts as a tumor suppressor. This enzyme regulates signaling pathways involved in cell growth and division. Individuals with the syndrome are born with one mutated copy of the gene. For tumors to develop, a second, somatic mutation must occur in a cell during the person's lifetime, resulting in the total loss of functional CYLD enzyme in that cell.
Inheritance
Susceptibility to the syndrome is inherited in an autosomal dominant pattern. Most individuals inherit the initial germline mutation from a parent. In rare cases, the mutation is not inherited but occurs as a somatic mutation early in development, resulting in mosaicism, where only some of the body's cells carry the mutation.