Huntington Disease via the HTT CAG Repeat Expansion
Use
Huntington disease (HD) is a progressive neurodegenerative disorder characterized by motor dysfunction, cognitive decline, and psychiatric disturbances. Its diagnosis through genetic testing is particularly crucial for individuals with a family history or relevant clinical features. HD's genetic cause is a CAG trinucleotide repeat expansion in the HTT gene, with the number of repeats correlating to age of onset and severity. This test offers nearly 100% diagnostic yield for symptomatic individuals with a familial history.
Special Instructions
This test confirms the presence of CAG repeat expansion in the HTT gene, aiding in the diagnosis of Huntington disease. For prenatal diagnosis based on family history, contact our genetic counseling team before sample submission. This ensures the ability to accept and process the case correctly.
Limitations
The test accurately detects and sizes alleles up to approximately 175 CAG repeats. Repeats larger than 175 are reported as 'expanded,' but size is not quantified beyond this range. The test is not validated for size calling greater than 175 repeats. Analytical sensitivity is 100% for calling CAG repeat lengths, and potential limitations include standard PCR limitations such as inefficient amplification in some cases.
New York Approved
Methodology
PCR-based (Repeat-Primed PCR)
Biomarkers
Result Turnaround Time
6-10 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Not provided
Minimum Volume
Not provided