title: Trends in genotype frequency resulting from breeding for resistance to classical scrapie in Belgium (2006 ˜ 2011).
abstract: In sheep, susceptibility to scrapie is mainly determined by codons 136, 154, and 171 of the PRNP gene. Five haplotypes are usually present (ARR, ARQ, ARH, AHQ, and VRQ). The ARR haplotype confers the greatest resistance to classical scrapie while VRQ renders animals most susceptible. In 2004, the European Union implemented a breeding program that promotes selection of the ARR haplotype while reducing the incidence of VRQ. From 2006 to 2011 in Belgium, frequency for the ARR/ARR genotypes increased from 38.3% to 63.8% (n = 6,437), the ARQ haplotype diminished from 21.1% to 12.9%, and the VRQ haplotype decreased from 2.0% to 1.7%. The status of codon 141, a determinant for atypical scrapie, was also evaluated. Out of 27 different breeds (n = 5,163), nine were abundant. The ARR/ARR frequency increased in eight of these nine major breeds. The selection program has had a major impact on the ARR haplotype frequency in Belgium. However, the occurrence of atypical scrapie represents a critical point for this program that warrants the continuous monitoring of scrapie. Additionally, genotype frequencies among the breeds varied greatly. Texel, a breed that is common in Belgium, can still be selected for due to its average ARR frequency.
authors: Pathology and Prionology, Veterinary and Agrochemical Research Centre (CODA-CERVA), 1180 Brussels, Belgium.
authors: Alexandre
authors: A
authors: Dobly
authors: Sara
authors: S
authors: Van der Heyden
authors: Stefan
authors: S
authors: Roels
mesh_terms: D000818:Animals; D001530:Belgium; D001947:Breeding; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D008297:Male; D012608:Scrapie / Q000235:genetics*; D012756:Sheep
keywords: PrP; genetics; prion diseases; ruminant; transmissible spongiform encephalopathy
references: Vet Res. 2008 Jul-Aug;39(4):19
references: 18187032
references: J Gen Virol. 2005 Jan;86(Pt 1):231-235
references: 15604451
references: Vet J. 2007 Mar;173(2):449-51
references: 16169265
references: Vet Rec. 2001 Sep 22;149(12):349-52
references: 11594380
references: Curr Mol Med. 2004 Jun;4(4):385-96
references: 15354869
references: Epidemiol Infect. 2009 Jun;137(6):787-91
references: 19351431
references: J Gen Virol. 2006 Dec;87(Pt 12):3737-3740
references: 17098992
references: Can J Vet Res. 2008 Jul;72(4):320-4
references: 18783020
references: J Gen Virol. 2004 Sep;85(Pt 9):2735-2740
references: 15302967
references: Vet Q. 1997 Sep;19(3):101-5
references: 9323849
references: Vet Res. 2007 Jan-Feb;38(1):65-80
references: 17156738
references: Vet Res. 2008 Jul-Aug;39(4):30
references: 18284908
references: Epidemiol Infect. 2010 Mar;138(3):384-92
references: 19678970
references: Vet Rec. 2003 Aug 16;153(7):202-8
references: 12956297
references: Neuropathol Appl Neurobiol. 2007 Aug;33(4):373-94
references: 17617870
references: BMC Vet Res. 2010 Apr 18;6:20
references: 20398417
references: BMC Vet Res. 2010 May 04;6:24
references: 20441587
references: Vet Res. 2008 Jul-Aug;39(4):28
references: 18284907
references: Vet Rec. 2004 Nov 27;155(22):707-8
references: 15605538
references: Arch Virol. 1996;141(5):809-24
references: 8678828
references: Emerg Infect Dis. 2011 Dec;17(12):2253-61
references: 22172149
references: Vet Rec. 2008 Oct 11;163(15):453-4
references: 18849578
references: Proc Biol Sci. 2007 Jun 22;274(1617):1497-503
references: 17412681
references: Trends Biochem Sci. 1996 Dec;21(12):482-7
references: 9009832
references: Vet Rec. 2006 Aug 19;159(8):247-50
references: 16921014
references: Am J Vet Res. 2007 Oct;68(10):1073-8
references: 17916013
references: Heredity (Edinb). 2010 Feb;104(2):122-3
references: 19707236
references: BMC Vet Res. 2010 May 14;6:25
references: 20470415
references: BMC Vet Res. 2008 Jun 10;4:19
references: 18544152
references: J Virol Methods. 2004 Apr;117(1):27-36
references: 15019257
references: Vet Rec. 2005 Apr 2;156(14):433-7
references: 15828723
references: J Comp Pathol. 1974 Jan;84(1):19-25
references: 4212154
references: Arch Virol. 1999;144(3):431-45
references: 10226611
references: Res Vet Sci. 2012 Aug;93(1):219-25
references: 21816449
references: J Gen Virol. 1993 Jun;74 ( Pt 6):1025-31
references: 8099602
references: J Gen Virol. 2006 Nov;87(Pt 11):3141-3149
references: 17030846
references: Arch Virol. 2007;152(6):1229-32
references: 17426916
references: Vet Q. 2004 Mar;26(1):3-11
references: 15072136
references: J Gen Virol. 1995 Mar;76 ( Pt 3):509-17
references: 7897344