No abstract

The polymorphism of the PRNP gene plays a key role in susceptibility to prion disease. Scrapie is a neurodegenerative disease affecting sheep and goats and belongs to the group of prion diseases. We isolated DNA from 333 goat samples representing the main local goat breeds in six provinces in China to identify PRNP polymorphisms and to determine whether these breeds were at risk for developing scrapie. Two novel amino acid polymorphisms (R211G and T219I) and a novel silent mutation at codon 125 as well as nine previously reported polymorphisms were observed. Twenty-eight alleles and forty-nine different genotypes were obtained. The codon 142M associated with resistance of goat scrapie was not found in this study. The codon 143R was relatively rare. The codon 222K, a potentially useful candidate site for selecting for scrapie resistance, was also rare in indigenous Chinese goats. These results could provide some useful data for assessing the risk of scrapie in Chinese indigenous goats.

Paraoxonase 1 (PON1) is an antioxidant enzyme that inhibits the oxidative modification of LDL. Since PON1 has been shown to express in pancreatic islets and oxidative stress plays a role in beta-cell dysfunction, we investigated the impact of the PON1 polymorphisms on beta-cell function. This study included 84 healthy and glucose-tolerant white subjects who underwent an oral glucose tolerance test. Beta-cell function (1stPHS and 2ndPHS) was estimated according to the formulae published by Stumvoll et al. The relationship of the L55M and Q192R polymorphisms to beta-cell function was examined. Allelic frequency in this population was 0.37 for the M allele and 0.30 for the R allele. For the L55M polymorphism, the LM genotype had the lowest 1stPHS (P = 0.009) and 2ndPHS (P = 0.007), indicating molecular heterosis. Multivariate analyses confirmed that the L55M polymorphism was an independent determinant for 1stPHS (P = 0.016) and 2ndPHS (P = 0.009), after adjustment for covariates. For the Q192M polymorphism, no difference was noted in 1stPHS and 2ndPHS. We observed the L55M polymorphism of the PON1 gene as an independent determinant for beta-cell function in glucose-tolerant whites. Our observations suggest that this polymorphism could play a role in beta-cell dysfunction.