Tuberous sclerosis - Diagnosing tuberous sclerosis

The length of time that it takes to make a successful diagnosis of tuberous sclerosis will depend on how severe a child's symptoms are.

For example, in a young child who quickly develops symptoms of epilepsy and kidney disease, tuberous sclerosis may immediately be suspected as an underlying cause. However, in children with few symptoms, a diagnosis may not be made until they develop patches on their skin, which can take several years.

Diagnostic checklist

Healthcare professionals use a checklist to help diagnose tuberous sclerosis. The checklist is made up of major and minor features. If a child has at least two major features, or one major and two minor features, it is likely that they have tuberous sclerosis.

The major features include:

• three or more facial angiofibromas – benign (non-cancerous) growths on the back of the nose or upper throat
• three or more patches of skin that are lighter than normal
• two or more skin lesions that grow under or around the fingernails and toes
• shagreen patches – a small area of raised skin with a texture similar to an orange peel, often found on the lower back
• eye tumour(s)
• brain tumour(s)
• heart tumour(s)
• lung tumour(s)
• kidney tumour(s)

The minor features include:

• more than three small pits in the teeth
• two or more small lumps or tumours in the gums
• nonrenal hamartomas – benign growths that do not affect the kidneys
• retinal achromic patch – a small area of the retina that is lighter in colour than the area surrounding it 
• "confetti" skin lesions on the face or body
• several fluid-filled holes (cysts) affecting the kidneys 

Testing for tuberous sclerosis

A number of tests can also help confirm a diagnosis of tuberous sclerosis. These are:

• an eye examination – eye tumours can often be the first sign of tuberous sclerosis
• a skin examination – an ultraviolet light is often used to examine the skin as it can reveal skin lesions that have lost their colour (depigmented), or white patches
• a magnetic resonance imaging (MRI) scan – these scans can often detect tumours within the brain
• a computerised tomography (CT) scan or an ultrasound scan – these scans can often detect tumours within the kidneys, heart or lungs
• an electroencephalogram (EEG) – a test that can detect abnormal electrical activity within the brain
• an electrocardiogram (ECG) – a test that can detect abnormal electrical activity within the heart