Interestingly, the preferential expression of the splice variants TGM2_V4a and v4b compared to full-length TG2 was recently reported in peripheral blood mononuclear cells derived from patients with primary progressive multiple sclerosis (PP-MS), suggesting that TG2 splice variants may function in the pathophysiology of PP-MS [19]. Here, TGM2 is linked to primary progressive multiple sclerosis.