The AR CAG repeat expansion has been shown to be the cause of X-linked spinobulbar muscular atrophy (SBMA) / Kennedy disease; a very rare disease clinically characterised by slowly progressive muscle weakness and atrophy with onset in adult males (usually in the fourth or fifth decade). Muscle cramps may precede the onset of weakness by several years. Symptoms are related to both spinal and bulbar motor neuron degeneration, including facial weakness, muscle weakness and atrophy, speech difficulty and coarse fasciculation. Affected individuals often show gynaecomastia, testicular atrophy and reduced fertility, as a result of mild androgen insensitivity.
Fluorescent PCR is used to perform this testing. The results of the assay can be visualised using GeneMarker software following fragment analysis on a genetic analyser. Positive and negative controls are included in each assay.
Test | Cost NZD | Sample requirements | Turnaround time |
AR CAG repeat expansion test | $158 | 4ml of whole blood in EDTA (lavender top) | 2 - 4 weeks For urgent cases please contact the laboratory |