On the other hand, a study by Colle and colleagues (2017) measured the BDNF level in 328 adult Caucasian MDD patients and found a significant difference in the plasma BDNF level among the genotypes (G/G: 1525.9±1183.3 pg/ml vs G/A: 1248.7±1081.8 pg/ml vs A/A: 1004.9±952.8 pg/ml, p = 0.04) [45]. Here, BDNF is linked to major depressive disorder.