Tuberous sclerosis can cause various symptoms that depend greatly on which area of the body is affected by the related tumors. Each individual may note different signs of the condition that differ greatly in presentation and severity.
The benign tumors characteristic of tuberous sclerosis commonly grow in the brain, kidneys, heart, eyes, lungs and skin. The symptoms that result from these tumors are tied to the location it affects and the bodily functions that are reliant on that organ.
The most commonly reported symptom of tuberous sclerosis is a change in the function of the brain, as a result of benign tumors that affect this major organ. There are three types of brain tumors including cortical tubers on the surface of the brain, subependymal nodules (SEN) in the walls of ventricles and subependymal giant-call astrocytomas (SEGA) that blow fluid flow within the brain.
The majority of individuals affected by tuberous sclerosis will experience seizures at some point due to the presence of tumors in the brain. Various types of seizures can present, including tonic-clonic, tonic, akinetic, atypical absence, and myoclonic seizures. Infantile spasms is also common among infants with the condition and is often the first symptom to be noted.
Approximately 60% of children with tuberous sclerosis have a developmental delay that can vary greatly in severity, from a mild learning disability to mental retardation. Some behavior problems may also present, such as aggression, attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD) and self-harming tendencies. About 1 in 3 of affected children meet diagnostic criteria for autism spectrum disorder.
Three-quarters of individuals with tuberous sclerosis report problems in kidney function due to benign cysts that affect the organ. These usually present in late teen years to 30 years old, and are usually small in size and cause limited inconvenience.
In some cases, the cysts may be larger in size or develop in bountiful quantity, similarly to polycystic kidney disease. Kidney function can be severely compromised and lead to kidney failure.
Angiomyolipoma is the term for a benign growth of muscle and fatty tissue, which is the most common type of tumor found in the kidney. Although they are common in people with tuberous sclerosis, they are also seen in people without the disease and are hence a non-specific sign. They do not usually cause symptoms but in some cases when they are particularly large pain, weakness and bleeding can occur.
Infants with tuberous sclerosis are often found to have cardiac rhabdomyomas, which are often detected before birth upon ultrasound examination of prenatal fetus. The severity depends on the size and number of the tumors and in some cases they can obstruct blood circulation from the heart and cause death.
However, if the tumors do not pose a major threat at birth, they are likely to shrink over time and do not usually affect adult individuals.
Phakomas are benign tumors that can be found in the eyes of patients with tuberous sclerosis. In most cases, they do not cause symptoms related to vision but their characteristic appearance with white patches on the retina can be used as a diagnostic indicator.
Women with tuberous sclerosis are more likely to have lesions in the lung than men. Whilst many individuals with the benign tumors are not symptomatic, some may suffer from breathlessness and other breathing difficulties.
There are various skin abnormalities that affect people with tuberous sclerosis, which may include:
- Hypomelanic macules – white patches on the skin
- Facial angiofibromas – reddish bumps on face
- Ungual fibromas – fleshy tumors around or under nails
These do not typically cause major problems but have a distinctive appearance and can help in diagnosis of the condition.