{{Rsnum
|rsid=28399504
|Gene=CYP2C19
|Chromosome=10
|position=94762706
|Orientation=plus
|ReferenceAllele=A
|MissenseAllele=G
|GMAF=0.001377
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|Summary=Clopidogrel (Plavix®)
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Gene_s=CYP2C19
}}{{CPMC SNP
|link=https://cpmc.coriell.org/Sections/Results/Plavix.aspx?PgId=212
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 0.0 | 0.0 | 0.0
| HCB | 98.5 | 1.5 | 0.0
| JPT | 0.0 | 0.0 | 0.0
| YRI | 0.0 | 0.0 | 0.0
| ASW | 0.0 | 0.0 | 0.0
| CHB | 98.5 | 1.5 | 0.0
| CHD | 0.0 | 0.0 | 0.0
| GIH | 0.0 | 0.0 | 0.0
| LWK | 0.0 | 0.0 | 0.0
| MEX | 98.3 | 1.7 | 0.0
| MKK | 0.0 | 0.0 | 0.0
| TSI | 0.0 | 0.0 | 0.0
| HapMapRevision=28
}}[[rs28399504]] is a SNP in the [[CYP2C19]] gene, potentially encoding the CYP2C19*4 variant. This variant has been linked to poor metabolism of compounds like mephenytoin. It is also known as M1V or Met1Val.{{PMID|9435198}}

The risk allele is [[rs28399504]](G).

As a nonfunctioning [[CYP2C19]], this variant would be expected to be a poor metabolizer of several commonly prescribed drugs, including anti-[[ulcer]] drugs like [[omeprazole]] (trade names [[Losec]] and [[Prilosec]]), [[esomeprazole]] (trade name [[Nexium]]), and [[lansoprazole]] ([[Prevacid]]).

According to [https://www.23andme.com/you/community/thread/1144/ a 23andMe discussion] This is one of the SNPs which were re-analyzed April 2009. Customers with older data may wish to redownload. SNPs effected [[rs4420638]], [[rs34276300]], [[rs3091244]], [[rs34601266]], [[rs2033003]], [[rs7900194]], [[rs9332239]], [[rs28371685]], [[rs1229984]], and [[rs28399504]].

{{omim
|desc=MEPHENYTOIN, POOR METABOLISM OF
|id=124020
|quiet=1
|rsnum=28399504
|variant=0004
}}

{{ neighbor
| rsid = 12248560
| distance = 806
}}

{{PharmGKB
|RSID=rs28399504
|Name_s=CYP2C19*4, CYP2C19:A1G
|Gene_s=CYP2C19
|Feature=Exon
|Evidence=PubMed ID:19106083
|Annotation=Subjects who had previously experienced myocardial infarction and were receiving clopidogrel were almost twice as likely to experience a subsequent cardiovascular event if they carried any two CYP2C19 loss-of-function alleles (CYP2C19*2, CYP2C19*3, CYP2C19*4 or CYP2C19*5) relative to those with none. Patients from this study who underwent percutaneous coronary intervention and carried two CYP2C19 loss-of-function alleles had a 3.58 times greater risk of cardiovascular events as those with none. These results suggest that treatment with clopidogrel is less effective in individuals who are homozygous for CYP2C19 loss-of-function alleles than in those who do not carry CYP2C19 loss-of-function alleles.
|Drugs=clopidogrel
|Drug Classes=
|Diseases=Cardiovascular Diseases; Death; Myocardial Infarction; Stroke
|Curation Level=Curated
|PharmGKB Accession ID=PA162363762
}}

{{PharmGKB
|RSID=rs28399504
|Name_s=CYP2C19*4; 1A>G; 99C>T; 80161A>G
|Gene_s=CYP2C19
|Feature=Exon
|Evidence=PubMed ID:9435198
|Annotation=This allele was examined in a European Caucasian population which had been phenotyped for mephenytoin metabolism. Based on the genotyping results the authors conclude that the defective nature of the CYP2C19*4 allele is shown by the fact that two Caucasian poor metabolizers were heterozygous for CYP2C19*2/CYP2C19*4. In vitro experiments showed no expression of CYP2C19*4 cDNA. The study calculated that the frequency of the CYP2C19*4 allele in Caucasians was 0.6%.
|Drugs=mephenytoin
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA162316733
}}
{{PMID Auto
|PMID=21247447
|Title=CYP2C19 and ABCB1 gene polymorphisms are differently distributed according to ethnicity in the Brazilian general population
|OA=1
}}

{{ClinVar
|rsid=28399504
|Reversed=0
|FwdREF=A
|FwdALT=G
|REF=A
|ALT=G
|RSPOS=96522463
|CHROM=10
|GMAF=0.0014
|dbSNPBuildID=125
|SSR=0
|SAO=1
|VP=0x050168000000040517110100
|GENEINFO=CYP2C19:1557
|GENE_NAME=CYP2C19
|GENE_ID=1557
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000010.10:g.96522463A>G
|CLNORIGIN=1
|CLNSIG=6
|Tags=PM;PMC;SLO;VLD;HD;GNO;KGPhase1;KGPROD;OTHERKG;PH3;LSD;OM
|CAF=0.9986; 0.001377
|CLNACC=RCV000018399.26
|CLNDBN=Mephenytoin, poor metabolism of
|CLNDSDB=MedGen
|CLNDSDBID=C1836024
|CLNSRC=OMIM Allelic Variant
|CLNSRCID=124020.0004
|COMMON=0
|Disease=Mephenytoin
}}

{{PMID Auto
|PMID=18547414
|Title=Genotyping panel for assessing response to cancer chemotherapy.
|OA=1
}}

{{GET Evidence
|gene=CYP2C19
|aa_change=Met1Val
|aa_change_short=M1V
|impact=pathogenic
|qualified_impact=Insufficiently evaluated pathogenic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs28399504
|overall_frequency_n=1
|overall_frequency_d=128
|overall_frequency=0.0078125
|n_genomes=1
|n_genomes_annotated=0
|n_haplomes=1
|n_articles=1
|n_articles_annotated=1
|in_omim=Y
|in_pharmgkb=Y
|pph2_score=0.135
|nblosum100=0
|autoscore=2
|webscore=N
|n_web_uneval=10
|summary_short=This variant creates the CYP2C19*4 haplotype which is associated with poor metabolism of mephenytoin.
}}

[[Clopidogrel Efficacy]]

{{PMID Auto
|PMID=23130019
|Title=Frequencies of 23 functionally significant variant alleles related with metabolism of antineoplastic drugs in the chilean population: comparison with caucasian and asian populations.
|OA=1
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | FTDNA}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}