Tay-Sachs Disease (HEXA) Sequencing and Deletion/Duplication

Casandra

Casandra Test Code AR68437Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3004486CPT Codes 81406, 81479

Tay-Sachs Disease (HEXA) Sequencing and Deletion/Duplication

Also known as: HEXA NGS

Clinical Use

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Use

The Tay-Sachs Disease (HEXA) Sequencing and Deletion/Duplication test is used for carrier screening or diagnostic testing for Tay-Sachs disease, particularly in individuals with a high risk due to ethnic background such as Ashkenazi Jewish or French-Canadian ancestry. The test identifies pathogenic variants in the HEXA gene which are associated with Tay-Sachs disease, a genetically inherited condition leading to HEXA enzyme deficiency. This deficiency results in neuronal deterioration and intellectual disability, with severity influenced by the specific genetic variants present.

Special Instructions

Specimens from New York clients will be sent to a New York state-approved laboratory as the test is not New York state approved. Informed consent is required for New York patients. Special consideration for French-Canadian individuals due to reduced detection sensitivity for a pathogenic 7.6kb deletion.

Limitations

The test detects variants only within or overlapping the coding regions and intron-exon boundaries of the HEXA gene. Certain variant types such as regulatory region variants and deep intronic variants are not identified by this assay. The 7.6kb deletion common in French-Canadian populations is detected, but with lower sensitivity. Single exon deletions and duplications, as well as precise breakpoints for large deletions or duplications, are not consistently determined. The test does not analyze noncoding transcripts and is not intended for detecting low-level mosaic or somatic variants, gene conversion events, complex inversions, translocations, mitochondrial DNA mutations, or repeat expansions.

Test Details