Tay-Sachs carrier screening in the genomics age: Gene sequencing versus enzyme analysis in non-Jewish individuals

Charles M. Strom, Noh Jin Park, Craig Morgan, Raynah Lobo, Beryl Crossley, Rajesh Sharma, Reuben Bonilla-Guerrero, Denise Salazar

Department of Genetics Quest Diagnsotics Nichols Institute, San Juan Capistrano, USA.

DOI: 10.4236/ojgen.2013.31007                

Abstract

Purpose: To compare the sensitivity of Hexosaminidase A (HexA) enzyme-based testing to gene sequencing for carrier detection in non-Jewish individuals. Methods: Blood samples were obtained from parents and relatives of affected patients at an annual Tay-Sachs and Allied Diseases Foundation meeting. A family history was taken for each individual. Samples were analyzed for leukocyte HexA activity, serum HexA activity and subjected to extensive gene sequencing. The results from these analyses were combined with our previously published data describing 34 obligate Tay-Sachs disease (TSD) carriers. Results: Twelve additional TSD carriers were detected in this study. Gene sequencing successfully identified all 12 carriers whereas enzyme analysis identified 11 of 12 carriers. This individual is a carrier of the B1 variant that is known to cause false negative results with enzyme testing. Combined data from 46 non-Jewish TSD carriers revealed that gene sequencing had a higher sensitivity rate than HexA enzyme-based testing (94% versus 87%) in non-Jewish TSD carriers. In our series, approximately 4% of non-Jewish TSD carriers have this mutation. Conclusions: HexA gene sequencing provides a higher sensitivity for TSD carrier detection than HexA based enzyme analysis in non-Jewish patients primarily due to the presence of individuals with the B1 variant.

Keywords

Tay-Sachs Screening; Gene Sequencing; Hexosaminidase A

Conflicts of Interest

The authors declare no conflicts of interest.

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