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 they affect and the bodily functions that are reliant on that organ.
Tuberous Sclerosis: Benign Tumors that Develop in Organs of Children and Adults
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 that are often reported in tuberous sclerosis, which include cortical tubers on the surface of the brain, subependymal nodules (SEN) in the walls of ventricles, and subependymal giant-call astrocytomas (SEGA).
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 are also common among infants with the condition and are 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 behavioral 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 the diagnostic criteria for autism spectrum disorder.
About 75% of individuals with tuberous sclerosis report problems in kidney function due to benign cysts that affect the organ. These are usually present between the late teen years up to the age of 30. The kidney tumors that arise due to tuberous sclerosis are usually small in size and cause limited inconvenience.
In some cases, the cysts may be larger in size or develop in bountiful quantities, similarly to polycystic kidney disease. Kidney function can be severely compromised in these cases, thus increasing the risk of kidney failure.
Angiomyolipoma is a benign growth of muscle and fatty tissue, which is the most common type of tumor found in the kidney. Although these tumors are common in people with tuberous sclerosis, they are also seen in people without the disease; therefore, this is a non-specific sign for tuberous sclerosis. Angiomyolipomas do not usually cause symptoms; however, in some cases where the tumors are particularly large, pain, weakness, and bleeding can occur.
Infants with tuberous sclerosis are often found to have cardiac rhabdomyomas, which are typically detected before birth upon ultrasound examination of the prenatal fetus. The severity of these tumors depends on the size and number of the tumors. In some cases, cardiac rhabdomyomas 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, these tumors do not cause symptoms related to vision; however, 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 lungs as compared to men. Whilst many individuals with 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. However, these skin abnormalities have a distinctive appearance that can help in the diagnosis of tuberous sclerosis.