CPT® Code 81181

Molecular genetic testing is a critical procedure used to identify mutations in various ataxin (ATXN) genes that are linked to spinocerebellar ataxia (SCA), a slowly progressive degenerative disorder affecting the cerebellum and spinal cord. This condition manifests through a range of symptoms that can differ based on which specific gene is mutated. Common symptoms associated with SCA include uncoordinated gait, known as ataxia, muscle stiffness or spasms, tremors, and difficulties with speech (dysarthria) and swallowing (dysphagia). Patients may also experience challenges with hand-eye coordination, involuntary eye movements (nystagmus), vision problems, sleep disturbances, and cognitive difficulties such as issues with learning, processing information, and memory retention. The ATXN7 gene, which is the focus of this analysis, is situated on the short (p) arm of chromosome 3 at position 14.1 (3p14.1). This gene contains a DNA allele characterized by a trinucleotide repeat sequence of three amino acids: cytosine-adenine-guanine (CAG). Typically, this repeat occurs between 4 to 35 times; however, in the case of spinocerebellar ataxia type 7 (SCA7), the allele can expand to between 37 and 306 repeats. Notably, SCA7 presents unique symptoms, including retinal degeneration and pigmentary macular dystrophy. The CPT® Code 81181 is utilized to report the ATXN7 (ataxin 7) gene analysis, specifically for the evaluation and detection of these abnormal (expanded) alleles.