From the Research
The ASPA enzyme assay is a highly sensitive and specific test for diagnosing Canavan disease, with values typically exceeding 95% when properly performed, as supported by the most recent study in 2022 1. This enzyme test measures ASPA activity in skin fibroblasts or blood leukocytes, with significantly reduced or absent activity indicating Canavan disease. The test is particularly valuable as a confirmatory diagnostic tool following suspicious clinical findings and MRI results showing characteristic white matter changes. For optimal results, samples should be collected before blood transfusions and properly preserved during transport to specialized laboratories. The high accuracy of ASPA enzyme testing stems from the direct measurement of the fundamental biochemical defect in Canavan disease - the inability to metabolize N-acetylaspartic acid (NAA) due to ASPA deficiency, as described in a study from 2014 2. This leads to NAA accumulation in the brain, causing the progressive neurological deterioration characteristic of the disease. While genetic testing for mutations in the ASPA gene provides definitive diagnosis, enzyme testing remains valuable, especially in populations with varied or unknown mutation profiles, as noted in a study from 2003 3. Some key points to consider when interpreting ASPA enzyme assay results include:
- The test measures ASPA activity, which is directly related to the ability to metabolize NAA
- Reduced or absent ASPA activity is indicative of Canavan disease
- The test is highly sensitive and specific when properly performed
- Samples should be collected and preserved properly to ensure accurate results
- Enzyme testing is a valuable diagnostic tool, especially in populations with varied or unknown mutation profiles, as discussed in a study from 2022 1. It's also important to consider the pathogenesis of Canavan disease, which involves the metabolism and transportation of NAA in the brain, as well as the hypothetical mechanisms whereby ASPA deficiency results in dysmyelination and a failure of normal brain development, as examined in a study from 2022 1. Overall, the ASPA enzyme assay is a highly accurate and valuable diagnostic tool for Canavan disease, and should be considered as part of a comprehensive diagnostic approach, as supported by the most recent and highest quality study from 2022 1.