Potashkin et al. [7] took advantage of splice variant-specific microarrays to identify a biosignature composed of 13 mRNAs (c5orf4, wls, macf1, prg3, eftud2, pkm2, slc14a1-s, slc14a1-l, mpp1, copz1, znf160, map4k1 and znf134) whose expression is altered in peripheral blood of early-stage PD patients. Here, MPP1 is linked to Parkinson disease.