The antibodies are measured by immunoprecipitation of MuSK that has been radioactively labelled.[14] Interestingly, MuSK antibodies are not found equally within the MG population worldwide, and their prevalence appears to correlate with latitude, being found most frequently in the northern hemisphere in MG patients who live within latitudes 30 and 50 N of the equator. This evidence concerns the gene MUSK and myasthenia gravis.