As shown by qPCR, the PD disease status had no effect on the expression of total MAPT, MAPT splice variant transcripts 0N, 1N, 2N, 3R and 4R MAPT, MAPT-AS1 and the synuclein genes SNCA, SNCB and SNCG, neither in ctx-fg nor in ctx-cbl (Fig. 2, Table 3). Here, SNCA is linked to Parkinson disease.