{{Rsnum
|rsid=76353203
|Chromosome=11
|Orientation=plus
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Gene=APOC3
|position=116830637
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|Gene_s=APOC3
}}

[[rs76353203]], also known as R19X, is a rare variant in the apolipoprotein C3 [[APOC3]] gene.

As reported in two large studies published in 2014, [[rs76353203]] one of several loss of function mutations in the [[APOC3]] gene associated with a >40% lower average triglyceride level in individuals carrying one [[rs76353203]](T) allele and a corresponding decrease in [[coronary artery disease]].{{PMID|24941082}}{{PMID|24941081}}

{{omim
|id=107720
|rsnum=76353203
|variant=0003
}}{{ClinVar
|rsid=76353203
|Reversed=0
|FwdREF=C
|FwdALT=T
|REF=C
|ALT=T
|RSPOS=116701353
|CHROM=11
|dbSNPBuildID=131
|SSR=0
|SAO=1
|VP=0x050168000000000002110100
|GENEINFO=APOC3:345
|GENE_NAME=APOC3
|GENE_ID=345
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000011.9:g.116701353C>T
|CLNSRC=OMIM Allelic Variant
|CLNORIGIN=1
|CLNSRCID=107720.0003
|CLNSIG=5
|CLNCUI=C3151467
|CLNDBN=Hyperalphalipoproteinemia 2
|Disease=Hyperalphalipoproteinemia 2
|CLNACC=RCV000019493.26
|Tags=PM;PMC;SLO;OTHERKG;LSD;OM
|CLNDSDB=MedGen:OMIM
|CLNDSDBID=C3151467:614028
}}{{PMID Auto
|PMID=19074352
|Title=A null mutation in human APOC3 confers a favorable plasma lipid profile and apparent cardioprotection.
|OA=1
}}