Buerger disease (BD) is a vascular disease of unknown etiology characterized by thrombotic occlusion of peripheral arteries. Smoking is a well-known risk factor of BD, but genetic factors may also play an etiological role. Because chronic infection such as oral periodontitis is suggested to be involved in the pathogenesis of BD, polymorphisms in genes responsible for infectious immunity might be associated with BD as genetic factors. In this study, 87 patients and 312 healthy controls were investigated for 26 polymorphisms in the genes for Toll-like receptor (TLR). It was found that single nucleotide polymorphism (SNP) rs5743599 (G>A) in TLR1 showed a nominal association, where the A allele frequency was increased in the patients (0.200 in the patients vs. 0.133 in the controls, odds ratio (OR)=1.63, 95% confidence interval (95%CI)=1.01–2.62, p=0.042). When the GG genotype was taken as a reference, the GA genotype conferred significantly high risk (OR=1.81, 95%CI=1.03–3.17, p=0.038). In addition, haplotype analysis of TLR1 locus showed that the frequency of a haplotype containing the G allele of rs5743599 was significantly decreased in the patients (0.003 in the patients vs. 0.028 in the controls, OR=0.10, 95%CI=0.01–0.99, permutation p=0.048), suggesting a TLR1 haplotype-linked genetic factor in association with BD. These findings implied that the pathogenesis of BD was at least in part controlled by the innate immunity via TLR10/TLR1 locus.

Endangered penguins are in need of the genetic management to estimate the risk for loss of genetic diversity from populations resulting from habitat fragmentation or inbreeding. However, as for genome diversity in penguin species, there are limited reports and it is insufficient to give useful and appropriate information. In the present study, we obtained the full length sequence of the MHC class II gene, which is expected to be a useful genetic marker for biodiversity in conservation genetics. The 4.4 kb genome region containing two novel genes was determined for nucleotide sequences using genomic DNA extracted from Humboldt penguin, by using the inverse PCR method. Homology analysis of MHC class II genes with those from other birds suggested that the novel two genes were alpha and beta genes. In addition, phylogenetic analysis suggested that the beta gene of penguins was clustered with the beta genes from waterfowl. These observations provide basic information on the structure of MHC class II locus to relieve the genetic diversity of penguin species.

Association study of cat MHC (Feline Leukocyte Antigen; FLA) genes with infectious and autoimmune diseases is expected for the development of veterinary medicine, because cats are one of the major companion animals in Japan. However, detailed polymorphism information of the FLA genes is limited in comparison to other animals, although polymorphism analysis in FLA genes has been in progress for a long time. To better understand the causes, we outlined characteristics of cats as companion, experimental and wild animal, a history of genomic analyses of the FLA genomic region and polymorphism analyses, and diseases and infections that may be associated with FLA in this review.