ABSTRACT
We analyzed the prion protein (PrP) genotype based on the codons 136, 154 and 171 and assigned to five risk groups (R1-R5) in healthy and scrapie-affected sheep in Slovakia. In healthy (asymptomatic) population, 119 Merino, 106 Improved Valachian, 117 Tsigai, and 48 Suffolk breeds were tested. Among the asymptomatic sheep, the low-risk genotypes R1 and R2 were most abundant in Suffolk (94%) and Merino (84%) breeds, followed by Tsigai (58%) and Improved Valachian (40%) breeds. The medium-risk group R3 was most frequent in Improved Valachian (31%) breed, followed by Tsigai (21%), Merino (10%), and Suffolk (6%) breeds. The occurrence of high-risk groups R4 and R5 was none in Suffolk breed, followed by Merino (6%), Tsigai (21%), and Improved Valachian (30%) breeds. Since 2003, altogether 48 cases of scrapie have been confirmed in Tsigai (38), Merino (4), Improved Valachian (2), Improved Valachian x Tsigai (3), and Suffolk (1) breeds. Among sheep with scrapie, Merino breed belonged to the medium-risk group R3. The majority of scrapie-affected Tsigai sheep were classified into high-risk R5 (50%) and medium-risk R3 (42%) groups. We showed an association of scrapie with medium- and high-risk groups of PrP genotype in Slovakia. In particular, the glutamine at position 171 appears to be of major importance for the susceptibility to scrapie.
Subject(s)
Polymorphism, Genetic , Prions/genetics , Scrapie/genetics , Sheep/genetics , Animals , Codon/genetics , Electrophoresis, Polyacrylamide Gel , Genetic Predisposition to Disease , Genotype , Molecular Sequence Data , Nucleic Acid Denaturation , Polymerase Chain Reaction , Sequence Analysis, DNA , SlovakiaABSTRACT
Alzheimer's disease (AD) is the most common type of dementia occurring in human population. The disorder is characterized clinically by memory loss and histopathologically by the presence of neurofibrillary tangles and senile plaques in patient's brain. Accuracy of the clinal diagnosis of AD is quite variable (-60 to 95 %), leaving a significant number of AD patients undiagnosed or falsely positively diagnosed. Therefore there is a requirement for biological markers, which would unambiguously discriminate living AD patients from other non-AD individuals. Until now a few diagnostic biomarkers for AD have been identified, which can be divided in two groups: protein markers and genetic markers. The most significant protein biomarkers are levels of tau proteins, ubiquitin and amyloid beta-peptides in cerebrospinal fluid (CSF). Among genetic AD markers, the most relevant are allelic variants of gene for apolipoprotein E and point mutations in genes coding for amyloid precursor protein and presenilin 1 and 2. Nevertheless, neither of recent biomarkers allow the ultimate AD diagnosis, because the disease is multifactorial and heterogenous. Identification of various subgroups of AD will help improvement in diagnoses and development of potent therapeutic drugs (Tab. 2, Fig. 2, Ref. 53).
