rs74315403
A SNP in the PRNP gene on chromosome 20. Its most notable genotype is A;G: PrP D178N pathogenic mutation - leads to CJD or FFI
- Gene
- PRNP
- Location
- Chr 204,699,752 (GRCh38)
- Highest magnitude
- 6.5Very important
- Tested on
- AncestryDNA
Genotypes
As shown in 23andMe and AncestryDNA files.
- A;GMost notableBadPrP D178N pathogenic mutation - leads to CJD or FFI
- G;GGoodPrP codon 178 (D) - non pathogenic variant
On SNPedia: (A;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Other PRNP SNPs
- rs74315405C;TGerstmann–Straussler–Scheinker syndromeVery important
- rs74315401C;TGerstmann–Straussler–Scheinker syndromeVery important
- rs74315402C;TGerstmann–Straussler–Scheinker syndromeVery important
- rs74315406A;GGerstmann–Straussler–Scheinker syndromeVery important
- rs74315410G;TGerstmann–Straussler–Scheinker syndromeVery important
- rs74315413A;GGerstmann–Straussler–Scheinker syndromeVery important
- rs74315414A;CGerstmann–Straussler–Scheinker syndromeVery important
- rs74315415C;TGerstmann–Straussler–Scheinker syndromeVery important
Notes
From SNPedia
Show notes, about 230 words
aka c.532G>A (p.Asp178Asn or D178N) 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. 2016 Nature essay about this mutation, discussing use of ExAC to estimate penetrance (which at least for this mutation, D178N, turns out to be high): http://www.nature.com/news/a-radical-revision-of-human-genetics-1.20779 A 2019 Wired magazine article chronicles the efforts of one couple to find a cure for FFI, including the mention of upcoming clinical trials for carriers of the D178N mutation. ==References== The initial discovery of the D178N mutation in a Finnish family Linkage analysis of 7 families indicated strong likelihood of developing Creuzfeldt-Jakob disease given the D178N mutation, with a LOD score of 5.30. 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.
A;G
This SNP creates a D178N mutation within the Prion Protein, which leads to inherited Creutzfeldt-Jakob disease or Fatal Familial Insomnia.
Source and license
Adapted from rs74315403 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.