In simple words: This lab test examines the TBP gene for changes that might indicate a genetic condition called spinocerebellar ataxia 17 (SCA17). This condition causes problems with movement, balance, and other neurological functions. The test looks for specific changes in the gene, called "expanded alleles," which are essentially extra-long repeats of a particular DNA sequence. While this test is often used to help diagnose SCA17, it's not the only test used, and the results need to be interpreted by a doctor.

This molecular pathology procedure analyzes the TBP (TATA box binding protein) gene to detect abnormal alleles, specifically expanded alleles. These expanded alleles typically involve an enlarged gene segment with excessive CAG/CAA nucleotide sequence repeats. While not exclusively for a single condition, this test commonly aids in diagnosing spinocerebellar ataxia 17 (SCA17), a hereditary disease with diverse symptoms, including psychiatric manifestations, dementia, muscle rigidity, and involuntary movements due to degeneration in the cerebrum, brainstem, and cerebellum.It can also be used to determine carrier status.

Example 1: A 45-year-old patient presents with progressive difficulty with balance and coordination, along with slurred speech.The physician suspects spinocerebellar ataxia and orders the 81344 test to assess the TBP gene for expanded alleles, to help determine if SCA17 is the cause., A 30-year-old woman whose father was diagnosed with SCA17 undergoes genetic testing with the 81344 code to determine if she inherited the expanded allele and is a carrier of the condition., A patient with a family history of SCA17 but currently no symptoms undergoes predictive testing using 81344. This helps assess their risk of developing the condition in the future.

Documentation should include the patient's symptoms, family history of neurological disorders, reason for testing, and the specific gene being tested.A signed order from a physician is also required.