Tuberous sclerosis complex (TSC) is a rare genetic disorder that causes non-cancerous tumours, known as hamartomas, to grow in many different organs of the body. The condition, which occurs in an estimated one in 6,000 live births worldwide, is often first identified during infancy or childhood, though symptoms can sometimes be so mild that the condition is not recognised until adulthood, or in some cases, not at all. The disorder is caused by mutations in the TSC1 or TSC2 genes and can lead to a wide range of symptoms, from mild skin changes to serious disabilities, depending on the location and size of the growths. There is currently no cure for tuberous sclerosis, but treatments are available to manage its symptoms effectively.
The primary organs affected by TSC include the brain, kidneys, heart, lungs, skin, and eyes. Because the condition varies dramatically in severity from person to person, its course is unpredictable. Symptoms are caused by the non-cancerous growths, which are overgrowths of cells and tissue. While the tumours are benign, their growth can lead to significant medical complications. The initial presentation of TSC is often linked to seizures, which are a common first symptom. In young children, a specific type of seizure known as infantile spasm may be observed, characterised by stiffening of the arms and legs and arching of the back and head. Other types of seizures, including focal seizures and tonic-clonic seizures, are also frequently experienced, and children with TSC often experience different types of seizures over time.
Symptoms and Manifestations
The symptoms of TSC are diverse and depend entirely on which parts of the body are affected by the tumours. They can range from mild to severe and may develop in infancy, childhood, or even years later in life.
Neurological and Developmental Symptoms Brain lesions are a hallmark of TSC and can manifest in several ways. The three main types of brain lesions are cortical tubers, subependymal nodules (SEN), and subependymal giant-cell astrocytomas (SEGA), which develop from SEN. Beyond seizures, TSC is strongly associated with developmental delays and a range of neuropsychiatric disorders, collectively referred to as TSC-associated neuropsychiatric disorders (TAND). These can include difficulties with thinking, reasoning, and learning. Mental health conditions such as autism spectrum disorder and attention-deficit/hyperactivity disorder (ADHD) are also common among individuals with TSC. Behavioural problems, including hyperactivity, self-injury, aggression, and challenges with social and emotional adjustment, are frequently reported.
Kidney Problems Kidney issues are common in individuals with TSC. These can include cysts and angiomyolipomas, which are benign growths made of fatty tissue and muscle cells. While these growths often do not cause symptoms, they can become very large, leading to pain, internal bleeding, or kidney failure.
Cardiac and Pulmonary Issues Growths in the heart (cardiac rhabdomyomas) are often present at birth and typically shrink as the child gets older. In the lungs, growths (lymphangioleiomyomatosis, or LAM) may develop, causing coughing or difficulty breathing, particularly during physical activity or exercise. Lung tumours are observed more frequently in females than in males.
Dermatological Manifestations Skin changes are the most common symptom of TSC. These can include patches of lighter skin (hypomagnetic macules), small areas of thickened, smooth or bumpy skin (shagreen patches), and raised, discoloured areas on the forehead (forehead fibrous plaques). Small, soft bumps may appear under or around the nails (ungual fibromas). Facial growths that resemble acne and begin in childhood are also a common feature.
Other Symptoms Eye problems can also occur, although they are not detailed in the provided source material. The wide variation in symptoms means that TSC may be misdiagnosed or go unrecognised for years, highlighting the importance of expert evaluation.
Diagnosis and Multidisciplinary Care
Due to the complexity and variability of TSC, comprehensive care is essential. Specialist clinics, such as the Tuberous Sclerosis Clinic at the Kennedy Krieger Institute, provide expert care for children, adolescents, and adults affected by TSC and their families. These centres emphasise tailored treatment regimens, as the severity of TSC varies dramatically. The initial step for patients is an initial evaluation by expert physicians and therapists, which may include additional testing to determine the extent of the condition.
The approach in such specialist centres is interdisciplinary, specifically designed to care for TSC patients with multiple medical needs and complexities. A thorough examination is conducted to understand each patient's unique requirements. The range of specialists involved typically includes:
- Assistive Technology
- Behaviour Psychology
- Child Neurology
- Child Psychiatry
- Educational Services
- Epilepsy (Surgery)
- Genetic Counseling
- Neurogenetics
- Neuroimaging
- Neurology
- Neurophysiology
- Neuropsychology
- Occupational Therapy
- Pediatric Cardiology
- Pediatric Dermatology
- Pediatric Epileptology
- Pediatric Nephrology
- Pediatric Neuro-Oncology
- Pediatric Ophthalmology
- Physical Therapy
- Sleep
- Social Work
- Speech Language Pathology
This collaborative model ensures that all aspects of the patient's health—physical, cognitive, and emotional—are addressed.
Research and Clinical Trials
Advancements in understanding and treating TSC are driven by ongoing research. Clinical care at leading institutes is often directly linked to research efforts, ensuring patients have access to the most innovative therapies. Physicians are committed to improving the lives of those with TSC by designing and participating in both clinical and pre-clinical research studies. Current research aims to use MRI technology and biomarkers to determine why some individuals experience severe symptoms while others have only mild manifestations.
Participation in clinical research is a critical component of improving care for people with TSC. Clinical trials help researchers learn more about the disorder and may lead to better methods for safely detecting, treating, or preventing the disease. All types of participants are needed—healthy individuals and those with the illness, across all ages, sexes, races, and ethnicities—to ensure study results are broadly applicable. For those interested in participating, information is available through resources such as the NINDS Clinical Trials site and NIH Clinical Research Trials and You. A searchable database of current and past federal and private clinical studies and research results can be found at ClinicalTrials.gov.
Additional research information can be accessed through the NIH RePORTER database, which includes links to publications and resources from funded projects. For research articles and summaries, PubMed is a valuable resource containing citations from medical journals. The Rare Diseases Clinical Research Network (RDCRN) also facilitates collaboration, study enrolment, and data sharing, with the Developmental Synaptopathies Consortium supporting natural history, imaging, and biomarker identification for TSC and related neurodevelopmental disorders.
Conclusion
Tuberous sclerosis complex is a multifaceted genetic disorder with a broad spectrum of symptoms, primarily driven by the growth of non-cancerous tumours in vital organs. Its unpredictability and variability require a personalised, multidisciplinary approach to care, focusing on managing symptoms such as seizures, developmental delays, kidney problems, and skin changes. Specialist clinics offer comprehensive evaluations and treatment from a wide array of medical disciplines. Furthermore, ongoing research and the opportunity to participate in clinical trials are vital for advancing the understanding and treatment of TSC, offering hope for improved outcomes for patients and families. For those affected by TSC, connecting with expert centres and research networks is a crucial step towards managing the condition effectively.