• T allele: Reduces the number of dopamine D2 receptors (in striatum) [R] [R] [R]

The Minor "T" allele is associated with:

  • Increased likelihood of heroin dependence (Chinese, but not Germans) [R] [R].
  • Parkinsons Disease (PD) [R]
  • Borderline personality disorder (among at-risk young adults from the United States, but not Hungary) [R]
  • Increased risk of regular smoking [R]

The Major "C" allele is associated with:

  • Increased risk of regular drinking [R]

This SNP is associated with (unknown which alleles):

  • Schizophrenia [R]
  • May play a causative role in Parkinsons disease development [R]
  • Response to clozapine in African-American sample but not in Caucasian samples [R]
  • Higher caffeine-induced anxiety [R]
  • Gilles de la Tourette Syndrome (GTS) [R]

Supplemental Information:

  • An SNP in an intron of the DRD 2 gene
  • Sometimes called the TaqIB polymorphism [R]
  • C/T alleles - also called B2/B1 [R]


Parent Gene: DRD2

Importance: 3
Less common allele: T = 25%
More common allele: C = 75%
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