From SNPedia
rs1801028 is a SNP in the dopamine D2 receptor DRD2 gene. A meta-analysis comprising 27 samples and over 3,707 schizophrenia patients concluded that Cys/Ser heterozygotes, i.e. rs1801028(C;G) genotypes, were at elevated risk for schizophrenia when compared to either homozygote genotype (rs1801028(C;C) or rs1801028(G;G)). The odds ratio was 1.4 (p<0.005).[PMID 16402354]
An earlier meta-analysis comprising over 9,000 schizophrenia patients concluded pretty much the same thing: the Cys311 (rs1801028(G)) allele frequency led to an odds ratio of 1.43 (CI: 1.16-1.78, p<0.001) for this risk allele.[PMID 12707934]
A study of ~120 Chinese patients with schizophrenia concluded that Cys/Ser heterozygotes may not respond to risperidone treatment as well as Ser/Ser homozygotes.[PMID 15140279]
A paper has been published describing mistakes made in assigning allele status for this SNP:
- [PMID 18154681] (free full text) Misassigned alleles can annihilate efforts to control quality in otherwise well-designed genetic association analyses. To date, the issue remains underreported, as is exemplified by studies of a diallelic DRD2 missense variant in schizophrenia. For this variant, allele frequency data have been either misassigned, or incorrectly cited on four consecutive occasions. Contrary to conjecture, low heterozygosity has not guarded against the error with regard to rs1801028, a SNP that features a canonical base pair transversion, G:C.
In the case of rs1801028, rs1801028(C) is the more common allele, encoding the amino acid Serine at position 311, whereas rs1801028(G) encodes a Cysteine.
[PMID 20046399] Genetic polymorphisms in dopamine- and serotonin-related genes and treatment responses to risperidone and perospirone
[PMID 19512960] Genetic diagnostics of functional variants of the human dopamine D2 receptor gene
