As tuberous sclerosis is a broad condition involving benign tumors that may present in various parts of the body, the symptoms can vary greatly and it can be difficult to make an accurate diagnosis.
The first notable sign of tuberous sclerosis for many individuals affected by the condition are seizures caused by tumors in the brain. However, some people are diagnosed after noting delayed development or abnormalities of the skin.
Cardiac rhabdomyoma may be present in infants and can often be detected with prenatal fetus ultrasound examination. If present, this is likely to pose problems for the infant at or soon after birth and generally reduces in size, decreasing the risk of complications, following this time.
Tumors in the brain that cause seizures are often the first sign noticed by individuals with tuberous sclerosis. Various types of seizures may occur, including infantile spasms that occur in young children.
A developmental delay resulting from tumors in the brain may also be a presenting sign of someone with the condition. This varies significantly in severity, from mild aggression to attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD) and self-harming tendencies.
Cysts in the kidneys, which may affect renal function, can also be indicative of tuberous sclerosis and usually present in individuals from 15 to 30 years old. Given the late presentation of this symptom, most individuals that experience this have already been diagnosed. Evidence of angiomyolipoma in the kidney is also common, but is a non-specific symptom of the condition.
White patches on the retina of the eyes are a diagnostic indicator of the presence of benign tumors in the eyes called phakomas. There are several skin abnormalities that also commonly affect people with tuberous sclerosis. This includes hypomelanic macules with white patches on the skin, facial angiofibromas presenting as reddish spots on the face and ungual fibromas with fleshy tumors under or around nails.
Medical and Family History
When an individual presents with signs that could be indicative of tuberous sclerosis, a thorough medical history should be taken as well as a family history of relevant conditions.
Tuberous sclerosis is a genetic disorder that is caused by mutations in the TSC1 or TSC2 genes, which can occur spontaneously or can be inherited from a parent that carries the gene. As it follows an autosomal dominant pattern, it can be inherited from either parent and it affects male and female children equally. The possibility of familial disease brings about the need to ask about family history of the disease during diagnosis. However, the mutation can also occur spontaneously without a family history of tuberous sclerosis
Diagnostic Imaging Techniques
Computer tomography (CT) or magnetic resonance imaging (MRI) scans of the brain can help to detect the presence of tubers in the brain.
For other organs that may be affected such as the heart, liver and kidneys, an ultrasound is usually indicated to investigate possible tumors in the area.
Classification of Diagnosis
Diagnosis of tuberous sclerosis can be classified as definite, probable or suspected, depending on the presenting signs of the individual. Definite cases exhibit 2 major signs of the disease, or one major and two minor signs. Probable cases have one major sign and one minor sign, whereas suspected cases have one major feature or several minor signs.
Major signs include:
- Facial angiofibromas or forehead plaque
- Ungual or periungual fibroma of the nails
- Hypomelanotic macules on the skin
- Shagreen patch on the skin
- Cortical tuber, subependymal nodule or astrocytoma in the brain
- Retina nodular hamartomas in the eyes
- Cardiac rhabdomyoma in the heart
- Lymphangioleiomyomatosis in the lungs
- Renal angiomyolipoma of the kidneys
Minor signs include:
- Randomly distributed pits in dental enamel of teeth
- Hamartomatous rectal polyps in the rectum
- Bone cysts
- Cerebral white matter in the brain
- Gingival fibromas on the gums
- Hamartoma of the liver, spleen or other organ
- Achromic patch on the retina of the eyes
- Confetti lesions on the skin