Tay Sachs Disease

Tay - Sachs disease (TSD) can be diagnosed through the use of tests and clinical evaluation. In a blood test screening, levels of hexosaminidase A are assessed using an enzyme assay (NORDs, n.a). Individuals with Tay-Sachs have reduced levels to almost absent amounts of this enzyme. Another way to diagnose Tay-Sachs is through the use of molecular genetic testing (NORDs, n.a). This method can find mutations in the HEXA gene, which is known to cause the disease. However, this diagnostic test is only offered at certain labs. Tay- Sachs can also be diagnosed prenatally through the use of screening such as chorionic villus sampling (CVS) and amniocentesis. CVS involves removing tissue samples from a part of the placenta and can be conducted around the 11th week of pregnancy (National Human Genome Research Institute, 2011). While in amniocentesis, it is done around the 16th week of pregnancy and involves the testing of a fluid sample surrounding the baby that is removed through the use of a needle National Human Genome Research Institute, 2011).

The Tay-Sachs disease carrier screening program was first started in Baltimore Maryland, in 1970 (Lew et al., 2014). Screening programs are important as it has been found that there is about a 90% decrease in the incidence of TSD cases in communities where these programs have been offered (Lew et al., 2014). A study by Gason et al. (2005), studied the efficacy of carrier screening programs in 2 Jewish schools in Melbourne students (ages 14-17) over a two year period. One of the components of the study involved assessing the compliance rate for blood sampling for the enzyme and genetic testing versus using a cheek brush method for solely genetic sampling. Until 2002, Jewish high school students were screened for TSD via an enzyme analysis, along with a mutation detection test. The cheek brush test method was implemented in 2003 and consisted of mutation analysis of the three common mutations found in the Ashkenazi Jewish populations. The study found that was a higher proportion of students who were tested for TSD carrier status via the cheek brush method (96%, N=214) compared to those who took a blood sample (84.9%, N=163). Researchers also saw that receiving a blood test caused more anxiety among the group 8.2% compared to those who received the cheek brush method 20.9%. Student attitudes were considered a powerful motivator for testing as there was a higher level of discomfort linked to blood testing.

In a review article by Lew et al (2014), there are several barriers to diagnosing TSD that are highlighted. On the clinician’s side, some of these include a lack of clinical education regarding the disease and failure to identify the genetic risk during their medical history. Other barriers include unplanned pregnancies and expenses incurred during testing for diagnosing (Lew et al., 2014). In Sydney Australia, having a test done for TSD costs a patient around $A100 (Lew et al., 2012). However even when obstacles such as cost and blood testing are removed, there is not always full maximization for carrier screening which makes diagnosis of TSD more difficult. In the study by Gason et al (2005), there were students at the high schools who simply did not feel that they wanted to know if they were carriers at this point in their life.

Gason, A. A., Metcalfe, S. A., Delatycki, M. B., Petrou, V., Sheffield, E., Bankier, A., & Aitken, M. (2005). Tay Sachs disease carrier screening in schools: educational alternatives and cheekbrush sampling. Genetics in Medicine, 7(9), 626-632.

Lew, R. M., Burnett, L., Proos, A. L., Barlow‐Stewart, K., Delatycki, M. B., Bankier, A., … & Fietz, M. (2015). Ashkenazi Jewish population screening for Tay–Sachs disease: The International and Australian experience. Journal of paediatrics and child health, 51(3), 271-279.