MID2 and Tinnitus: Furthermore, evidence of causal effects of tinnitus on six types of enzymes including Serine protease 27 levels, Phospholipase D3 measurement, Inactive peptidyl-prolyl cis-trans isomerase FKBP6, Probable E3 ubiquitin-protein ligase MID2, Ubiquitin-like modifier-activating enzyme ATG7, Aldo-keto reductase family 1 member C1 was also detected.<h4>Conclusions</h4>The present study suggests a causative effect of specific types of enzymes on tinnitus, as well as a reverse causality between them.