PRNP gene variation in Pakistani cattle and buffaloes

Area of Science:

• Veterinary Genetics
• Prion Disease Research
• Animal Health

Background:

• Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disease in cattle caused by prion protein misfolding.
• Classical and atypical (H-type, L-type) BSE forms exist, with atypical forms often being sporadic.
• Genetic polymorphisms in the prion protein gene (PRNP) are linked to BSE susceptibility, but data on Pakistani livestock is lacking.

Purpose of the Study:

• To assess the prevalence of specific PRNP gene polymorphisms (E211K, 23 bp indel, 12 bp indel) in Pakistani cattle and buffaloes.
• To evaluate the potential association of these polymorphisms with susceptibility to classical BSE in the studied populations.
• To compare allele and genotype frequencies with global data to infer relative BSE resistance.

Main Methods:

• Genotyping of 236 cattle (7 breeds) and 281 buffaloes (5 breeds) using triplex PCR.
• Screening for E211K polymorphism and 23 bp and 12 bp insertion/deletion (indel) polymorphisms in the PRNP gene.
• Statistical analysis of allele, genotype, and haplotype frequencies.

Main Results:

• The E211K polymorphism was not detected in any animals.
• The 23 bp insertion allele was underrepresented, while the 12 bp insertion allele was overrepresented in Pakistani cattle.
• Both 23 bp and 12 bp insertion alleles were highly prevalent in Pakistani buffaloes, with insertion alleles comprising nearly 90% of those studied.

Conclusions:

• Pakistani cattle exhibit distinct allele frequencies for PRNP indels compared to global populations, with a high frequency of the 12 bp insertion allele potentially conferring increased resistance to classical BSE.
• Buffalo populations show a strong prevalence of insertion alleles in the studied PRNP regions.
• While genetic factors play a role, dietary exposure remains the primary risk factor for classical BSE.