CPT® Code 81244

FMR1 (fragile X messenger ribonucleoprotein 1) (eg, fragile X syndrome, X-linked intellectual disability [XLID]) gene analysis; characterization of alleles (eg, expanded size and promoter methylation status)

The CPT® Code 81244 pertains to the molecular genetic testing of the FMR1 gene, which is crucial for diagnosing conditions such as Fragile X syndrome and X-linked intellectual disability (XLID). This gene is located on the X chromosome and is responsible for coding the fragile X messenger ribonucleoprotein 1 (FMR1 protein). The FMR1 protein plays a vital role in the development of normal synapses in the brain, particularly in processes related to synaptic plasticity, which is essential for learning and memory. A properly functioning FMR1 protein is necessary for normal cognitive development and female reproductive health. Mutations in the FMR1 gene can lead to a range of disorders, including Fragile X syndrome, mental retardation, autism spectrum disorders, premature ovarian failure, and even Parkinson's disease. The gene's normal sequence consists of a repeating pattern of cytosine-guanine-guanine (CGG) nucleotides, which can vary in number. Typically, this segment repeats between 4 and 44 times. However, when the repeats increase to between 45 and 54, individuals may be at borderline risk for expressing characteristics of Fragile X syndrome. A pre-mutation is identified when the repeats range from 55 to 200, while a full mutation occurs with more than 200 repeats. The analysis performed under CPT® Code 81244 specifically characterizes these alleles, including their expanded sizes and the status of promoter methylation, which is critical for understanding the potential risks and manifestations of associated conditions.