Rs1799990

rs1799990, also known as Met129Val or M129V, is a SNP in the prion protein PRNP gene. The more common rs1799990(A) allele encodes the Met (methionine).

Historically, since 1991 this SNP has been associated with risk for sporadic Creutzfeldt-Jakob disease, with homozygotes of both types apparently at increased risk compared to heterozygotes.

More recently, this SNP has been related to long-term memory with (A;A) and (A;G) individuals recalling 17% more words than (G;G) individuals at 24h following learning.

A further study of 12 individuals of each of the 3 possible genotypes showed that at both 30 minutes and 24 hour time lags, correlations between retrieval-related brain activity and retrieval success were negative for (G;) homozygotes (the more activity, the worse retrieval success), while correlations showed no significance or were positive for (A) homozygotes and heterozygotes. These findings suggest that the rs1799990 SNP affects neural plasticity following learning at a time-scale of minutes to hours.

rs1799990(A;G) heterozygotes were significantly overrepresented (age-adjusted odds ratio, 8.47) in 39 individuals with primary progressive aphasia (PPA), a rare condition of unknown cause, compared to 400+ controls.