{{Rsnum
|rsid=6413438
|Orientation=plus
|ReferenceAllele=C
|MissenseAllele=T
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Chromosome=10
|position=96541615
|Gene=CYP2C19
|Assembly=GRCh37
|GenomeBuild=37.1
|dbSNPBuild=131
}}{{ population diversity
| geno1=(C;C)
| geno2=(C;T)
| geno3=(T;T)
| CEU | 100.0 | 0.0 | 0.0
| HCB | 100.0 | 0.0 | 0.0
| JPT | 100.0 | 0.0 | 0.0
| YRI | 100.0 | 0.0 | 0.0
| ASW | 0.0 | 0.0 | 0.0
| CHB | 100.0 | 0.0 | 0.0
| CHD | 0.0 | 0.0 | 0.0
| GIH | 91.7 | 8.3 | 0.0
| LWK | 0.0 | 0.0 | 0.0
| MEX | 0.0 | 0.0 | 0.0
| MKK | 96.6 | 3.4 | 0.0
| TSI | 0.0 | 0.0 | 0.0
| HapMapRevision=28
}}The [[rs6413438]](T) allele defines the [[CYP2C19]] allele known as CYP2C19*10. This allele may lead to reduced metabolism of S-mephenytoin at least in vitro.{{PMID|12464799}}

{{PharmGKB
|RSID=rs6413438
|Name_s=CYP2C19:680C>T; 19153C>T; P227L
|Gene_s=CYP2C19
|Feature=
|Evidence=PubMed ID:12464799
|Annotation=This variant is the defining SNP for CYP2C19*10. This variant is associated with reduction in the metabolism of S-mephenytoin in vitro.
|Drugs=mephenytoin
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA162355681
}}

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