{{Rsnum
|rsid=74315403
|Chromosome=20
|Orientation=plus
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Gene=PRNP
|position=4699752
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|Gene_s=PRNP
}}{{omim
|id=176640
|rsnum=74315403
|variant=0007
}}
{{omim
|id=176640
|rsnum=74315403
|variant=0010
}}{{ClinVar
|rsid=74315403
|Reversed=0
|FwdREF=G
|FwdALT=A
|REF=G
|ALT=A
|RSPOS=4680398
|CHROM=20
|dbSNPBuildID=131
|SSR=0
|SAO=1
|VP=0x050368000000000002110100
|GENEINFO=PRNP:5621
|GENE_NAME=PRNP
|GENE_ID=5621
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000020.10:g.4680398G>A
|CLNSRC=GeneReviews; OMIM Allelic Variant
|CLNORIGIN=0
|CLNSRCID=NBK1229; 176640.0007; 176640.0010
|CLNSIG=5
|CLNCUI=C0162534
|CLNDBN=Jakob-Creutzfeldt disease; Fatal familial insomnia; Genetic prion diseases
|Disease=Jakob-Creutzfeldt disease; Fatal familial insomnia; Genetic prion diseases
|CLNACC=RCV000014336.22; RCV000014337.23; RCV000020248.1; RCV000032588.22
|Tags=PM;PMC;S3D;SLO;OTHERKG;LSD;OM
|CLNDSDB=GeneReviews:MedGen:OMIM:Orphanet:SNOMED_CT; GeneReviews:MedGen
|CLNDSDBID=NBK1229:C0022336:123400:204:792004; NBK1229:C0206042:600072:466:83157008; NBK1229:C0162534
}}

This SNP codes for residue 178 of the Prion protein gene. Normally Aspartate, a polymorphism can create the D178N mutation which is linked to inherited [[Creutzfeldt-Jakob disease]] or [[Fatal Familial Insomnia]]. A number of factors influence this, including PrP codon 129, [[Rs1799990]], with 129MM homozygotes being more likely to develop Fatal Familial Insomnia.

==References==
{{PMID Auto
|PMID=12420099
|Title=Mutations of the prion protein gene phenotypic spectrum.
}}

{{PMID|1671440}} The initial discovery of the D178N mutation in a Finnish family

{{PMID|1353341}} Linkage analysis of 7 families indicated strong likelihood of developing Creuzfeldt-Jakob disease given the D178N mutation, with a LOD score of 5.30.

{{PMID|16227536|OA=1
}} Clinical, pathological, and genetic data were determined for a number of D178N patients, showing that symptoms lay on a spectrum from typical Creutzfeldt-Jakob disease to Fatal Familial Insomnia.