Tuberous sclerosis complex (TSC) is a genetic disorder that causes non-malignant tumors to form in many different organs, primarily in the brain, eyes, heart, kidney, skin and lungs. The aspects of TSC that most strongly impact quality of life are generally associated with the brain: seizures, developmental delay, intellectual disability and autism. Approximately 85 percent of individuals experience seizures during their lifetime, and about one-third of these manifest as infantile spasms, a devastating form of epilepsy occurring in early childhood. Autism occurs in approximately 50 percent of individuals with TSC, and other behavioral and psychiatric symptoms—such as aggression and anxiety—are quite common and are now known as TSC-Associated Neuropsychiatric Disorders (TAND). The incidence and severity of the various aspects of TSC can vary widely among individuals, even between identical twins.
At least two children born each day will have tuberous sclerosis complex. Current estimates place tuberous sclerosis complex-affected births at one in 6,000. Nearly 1 million people worldwide are estimated to have TSC, with approximately 50,000 in the United States. Many cases may remain undiagnosed for years or decades due to the relative obscurity of the disease and the mild form symptoms may take in some people.
In 2000-2001, three studies reported that between 26% and 39% of women with a definite diagnosis of TSC have evidence of LAM (Costello et al., 2000; Franz et al., 2001; Moss et al., 2001). Several subsequent studies suggested the frequency of lung involvement in adult women with TSC may be even higher, ranging from 42% to 49% (Muzykewicz et al, 2009; Adriaensen et al, 2011; Cudzilo et al., 2013). Importantly, in many of these women the disease does not cause significant respiratory symptoms.
Because of the wide variety of symptoms associated with this disease, TSC can be considered a “linchpin” disease since breakthroughs in TSC can lead to breakthroughs in other diseases, including autism, epilepsy and even cancer.
Lymphangioleiomyomatosis (LAM) is a progressive and often fatal lung disease that typically strikes young women. The average age of diagnosis is 34. LAM is characterized by an abnormal growth of smooth muscle cells in the lungs. These cells invade lung tissues, including the airways, blood and lymph vessels. Although these cells are not considered cancerous, they grow uncontrollably within the lungs. Over time, the cells produce materials that break down tissue causing the formation of cysts. The delicate architecture of the lungs is destroyed and the airflow is blocked, limiting the delivery of oxygen to the rest of the body. Ultimately women with LAM require supplemental oxygen and may face the need for a lung transplant or death.
The prevalence of LAM is difficult to know because it is frequently misdiagnosed as emphysema, bronchitis, allergies or asthma. There are 1,400 known cases of LAM in the United States and estimates that another 15,000 – 30,000 exist worldwide. Women with LAM suffer from shortness of breath, chest pain, fatigue and lung collapses.