In simple words: This test analyzes the ATXN2 gene in your blood or other sample to look for specific changes, called expanded alleles. These changes are linked to a condition called spinocerebellar ataxia type 2 (SCA2), a disease that affects movement and coordination. The test helps doctors diagnose SCA2 or see if someone carries the gene that could cause the disease in their children.

This code represents a laboratory test that analyzes the ATXN2 gene to detect the presence of abnormal alleles, specifically expanded alleles. These expanded alleles are typically caused by an enlarged gene segment with an excessive number of CAG nucleotide sequence repeats. The test is often used to aid in diagnosing spinocerebellar ataxia type 2 (SCA2), a heritable neurodegenerative disorder, or to determine carrier status for SCA2. The procedure includes all analytical steps involved in the test, from nucleic acid extraction to amplification and detection.

Example 1: A 45-year-old patient presents with progressive difficulty with balance and coordination, slurred speech, and involuntary eye movements. The physician suspects spinocerebellar ataxia and orders the 81179 test to evaluate for SCA2., A 30-year-old woman with a family history of SCA2 wants to know if she is a carrier of the disease. Genetic counseling is provided, and the 81179 test is ordered to determine her carrier status., A patient with a confirmed diagnosis of amyotrophic lateral sclerosis (ALS) undergoes genetic testing to identify potential contributing factors or genetic modifiers. The 81179 test is included in the panel to assess for intermediate-length expansions of the ATXN2 gene, which have been linked to increased ALS susceptibility.

The required documentation for 81179 includes the patient's medical history, family history of neurological disorders, relevant physical exam findings, and the physician's order for the test. The report should document the test methodology, the presence or absence of expanded alleles in the ATXN2 gene, and the interpretation of the results in the context of the patient's clinical presentation.