Causes

Researchers do not know the exact cause of LAM or why it mainly affects women, but they believe genes and the female hormone estrogen play a role.

Genes

People with LAM or TSC-LAM have abnormal TSC1 or TSC2 genes. These genes are known to cause another rare genetic disease called tuberous sclerosis complex (TSC).

Abnormal TSC genes make proteins that cannot control cell growth and cell movement in the body. As a result, abnormal muscle-like cells begin to grow out of control in certain organs or tissues, such as the lungs, kidney, and lymph nodes. These abnormal cell growths cause the signs, symptoms, and complications of LAM.

Estrogen hormone

Estrogen is thought to play a role in LAM because the condition:

• Primarily affects women.
• Worsens in a pattern that matches up with a women’s menstrual cycle, during pregnancy, and after using medicines such as birth control that contain estrogen.
• Has been known to stop worsening in some women who have entered menopause.

Visit Treatment to read the latest clinical recommendations about not using hormone therapy to treat LAM.