Table 1 Candidate polymorphisms for major depressive disorder

5-Hydroxytryptamine (serotonin) transporter (5-HTT)

5-HTTLPR [88, 89], STin2 [90]

17q11.1-q12

Tryptophan hydroxylase (TPH) 1

A218C [95], A779C [94, 95]

11p15.3-p14

Catechol-O-methyltransferase (COMT)

Val158Met [98–100]

22q11.2

Serotonin receptor (5-HTR) 1A

C-1019G [106]

5q11.2-q13

Brain-derived neurotrophic factor (BDNF)

Val66Met [111–115]

11p13

Norepinephrine transporter (NET)

T-182C [118], G1287A [119]

16q12.2

Tyrosine hydroxylase (TH)

VNTR (5–11 repeats of TCAT) [122–125]

11p15.5

Dopamine 2 receptor (DRD2)

−141C Ins/Del [131, 132], Ser311Cys [133], C32806T [134, 135]

11q23.1

Dopamine 3 receptor (DRD3)

Ser9Gly [136]

3q13.3

Dopamine 4 receptor (DRD4)

48 repeats in exon 3 [138]

11p15.5