Prevalence of the prion protein gene E211K variant in U.S. cattle.
BACKGROUND
In 2006, an atypical U.S. case of bovine spongiform encephalopathy (BSE) was discovered in Alabama and later reported to be polymorphic for glutamate (E) and lysine (K) codons at position 211 in the bovine prion protein gene (Prnp) coding sequence. A bovine E211K mutation is important because it is analogous to the most common pathogenic mutation in humans (E200K) which causes hereditary Creutzfeldt - Jakob disease, an autosomal dominant form of prion disease. The present report describes a high-throughput matrix-associated laser desorption/ionization-time-of-flight mass spectrometry assay for scoring the Prnp E211K variant and its use to determine an upper limit for the K211 allele frequency in U.S. cattle.


RESULTS
The K211 allele was not detected in 6062 cattle, including those from five commercial beef processing plants (3892 carcasses) and 2170 registered cattle from 42 breeds. Multiple nearby polymorphisms in Prnp coding sequence of 1456 diverse purebred cattle (42 breeds) did not interfere with scoring E211 or K211 alleles. Based on these results, the upper bounds for prevalence of the E211K variant was estimated to be extremely low, less than 1 in 2000 cattle (Bayesian analysis based on 95% quantile of the posterior distribution with a uniform prior).


CONCLUSIONS
No groups or breeds of U.S. cattle are presently known to harbor the Prnp K211 allele. Because a carrier was not detected, the number of additional atypical BSE cases with K211 will also be vanishingly low.
Heaton
Michael P
MP
USDA, ARS, U, S, Meat Animal Research Center (USMARC), State Spur 18D, P.O. Box 166, Clay Center, NE 68933, USA. mike.heaton@ars.usda.gov
Keele
John W
JW
Harhay
Gregory P
GP
Richt
Jürgen A
JA
Koohmaraie
Mohammad
M
Wheeler
Tommy L
TL
Shackelford
Steven D
SD
Casas
Eduardo
E
King
D Andy
DA
Sonstegard
Tad S
TS
Van Tassell
Curtis P
CP
Neibergs
Holly L
HL
Chase
Chad C
CC
Kalbfleisch
Theodore S
TS
Smith
Timothy P L
TP
Clawson
Michael L
ML
Laegreid
William W
WW
D000818:Animals; D002417:Cattle / Q000235:genetics*; D003062:Codon / Q000235:genetics; D016643:Encephalopathy, Bovine Spongiform / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D014644:Genetic Variation; D006239:Haplotypes; D008297:Male; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D011328:Prions / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014481:United States
D003062:Codon; D011328:Prions