LAM Causes and Risk Factors

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Most often, LAM is caused by mutations (changes) in the structure of one of two tuberous sclerosis complex (TSC) genes, called TSC1 and TSC2. Abnormal muscle-like cells that carry these mutations appear and grow out of control in the lungs, kidneys, or lymph nodes. These LAM cells may initially develop in the uterus or elsewhere, but when they travel to the lungs, they produce the respiratory symptoms of LAM.

Researchers believe the hormone estrogen plays a role, because the condition affects mostly women between puberty and menopause. The condition also gets worse during pregnancy and after using medicines with estrogen, such as birth control. After menopause, LAM sometimes stops getting worse.

There is no way to prevent LAM. If you have TSC, your healthcare provider may recommend that you not smoke or take medicine with estrogen. This may help slow down the development of LAM. Medicines may stop abnormal LAM cells from increasing in number and may reduce their size. If you have TSC-LAM, your provider may recommend genetic counseling before you get pregnant to help you understand the risk of passing TSC and LAM on to your children.