Diagnosis of Batten Disease
The only sure way to confirm a Batten disease diagnosis is through genetic testing. To perform a genetic test, the patient’s DNA is purified from a blood sample. When Batten disease is suspected, families may undergo genetic counseling to discuss the likelihood of the condition and to help interpret the results of a genetic test.
Blood tests are a common diagnostic tool for identifying abnormally shaped lymphocytes in certain types of Batten disease. A blood test is a minimally invasive, low cost, and rapid way to screen for Batten disease. Results of blood tests should be confirmed with a genetic test.
An enzyme assay is a biochemical test in which the activity of a particular enzyme is measured. The results of this test, compared with control samples, gives an estimate of how severe the disease is and how fast it may progress. In both infantile and late infantile Batten disease, patients with no TPP1 or PPT1 enzyme activity seem to progress more rapidly.
Various eye-related tests can be used to identify Batten disease symptoms, including electroretinograms, autofluorescence imaging, and optical coherence imaging. These eye tests are generally low risk. An electroretinogram may cause slight discomfort and has a minor risk of scratching the eye. If this occurs, the patient is treated with antibiotics to prevent infections.
Tests of Brain Changes
Batten disease is marked by both brain atrophy and seizures linked to excessive and uncontrolled electrical signaling between brain cells. Imaging and other tests can detect these disease hallmarks by measuring changes in brain structures or activity. These include computed tomography scans, magnetic resonance imaging, and electroencephalogram.
In some cases, a tissue biopsy may be carried out to check for signs of Batten disease. A tissue biopsy is a minor procedure to remove a small piece of tissue from the patient, which is then examined under a microscope to check for known abnormalities, or used in other tests. In Batten disease, the most common type of biopsy is a skin biopsy.
Batten disease patients sometimes need to undergo urine tests to help physicians diagnose their condition. Although Batten disease can be confirmed only through genetic testing, a number of studies have suggested that testing urine for a substance known as dolichol may be useful in aiding the diagnosis.