PTK2 and major depressive disorder: MR further established JUN and PTK2 as causal genetic risk factors for depression (JUN: Odds Ratio (OR) = 1.029, 95% CI = 1.002–1.057; PTK2: OR = 1.040, 95% CI = 1.005–1.076; JUN (OR) = 1.048, 95% CI = 1.021–1.076, PTK2: OR = 1.073, 95% CI = 1.039–1.109) of each MR estimates, while other candidates lacked genetic support.