Background— Interleukin (IL)-18 plays a key role in atherosclerosis and its complications. The present study investigated the genetic variability of 4 genes of the IL-18 system— IL18 , IL18R1 , IL18RAP , and IL18BP —in relation to circulating IL-18 levels and cardiovascular mortality. Methods and Results— Twenty-two polymorphisms were genotyped in 1288 patients with coronary artery disease prospectively followed up during a median period of 5.9 years. The end point was death from cardiovascular causes (n=142). Baseline IL-18 levels were predictive of cardiovascular deaths occurring during ≤4 years of follow-up (HR=2.96, 95% CI 1.54 to 5.70, P =0.001 for the top compared with the bottom quartile) but not of later deaths. Haplotypes of the IL18 gene were associated with IL-18 levels ( P =0.002) and cardiovascular mortality ( P =0.006) after adjustment for cardiovascular risk factors. The same haplotype was associated with both a 9% lowering effect on IL-18 levels and a protective effect on risk (HR=0.57, 95% CI 0.36 to 0.92). IL18 haplotypes explained only 2% of IL-18 variability. Adjustment for baseline IL-18 levels abolished the association of haplotypes with cardiovascular risk. The haplotype associated with phenotypes was the only one carrying the minor allele of the IL18 /A+183G polymorphism located in the 3′untranslated region and potentially affecting mRNA stability. The other genes of the system were not related to IL-18 levels or cardiovascular outcome. Conclusion— Variations of the IL18 gene consistently influence circulating levels of IL-18 and clinical outcome in patients with coronary artery disease, which supports the hypothesis of a causal role of IL-18 in atherosclerosis and its complications.
Idiopathic Sertoli cell-only syndrome (SCOS) Is characterized by azoospermia, small testes, absence of germ cells In the testes, elevated Mick stimulating hormone and normal testosterone concentrations. The Y-chremosome is involved in the regulation of spermatogenesis and in the pathogenesis of a fraction of idiopathic male infertility. An azoospermia factor (AZF) is present on the Y-chromosome long arm euchromatic region (Yq11) and two gene families (DAZ and RBM) have been identified within this region. The aim of this study was to investigate whether a specific pattern of Yq 11 microdeletions may be associated with idiopathic SCOS. Eighteen idiopathic subjects showing a testicular cytological picture of bilateral SCOS were selected and tested by polymerase chain reaction for a set of 29 Y-specific sequence-tagged sites (STS). We found Yq microdeletions in 10 out of 18 patients (55.5%) while the fathers or brothers of six out of 10 patients deleted for Yq were shown to carry an intact Y-chromosome. These deletions may therefore be considered as de-novo deletions and the cause of SCOS. The analysis of the microdeletions allowed us to identify two homogeneous regions that have a high incidence of deletion. The smallest deletion, common to all patients, is located in Yq interval 5. We therefore speculate that there is a relationship between specific, well-characterized Yq11 microdeletions and a testicular picture of SCOS, identifying an Y-related region frequently deleted in this syndrome. In conclusion, the findings of this study demonstrate that a large percentage of idiopathic SCOS may be genetically determined and identify an Y-related region that seems to possess one or more still unknown genes essential for spermatogenesis.
P-selectin is a cellular adhesion molecule that may be involved in the development of atherosclerosis and its complications. We have previously identified thirteen polymorphisms of the P-selectin gene among which five were located in the coding region of the gene (S290N, N562D, V599L, T715P, T741T (A/G)). These polymorphisms were tested individually for association with myocardial infarction (MI) and only the T715P polymorphism was shown to be associated with MI. We here extend this work by performing a haplotype analysis which enables us to assess the consequences on the phenotype of the co-presence of several variants on the same chromosome. For this purpose, a new maximum likelihood method was developed for estimating simultaneously haplotype frequencies and haplotype–phenotype effects. While haplotypes defined by the polymorphisms located in the promoter region of the gene were unrelated to MI, those defined by the polymorphisms in the coding region were globally associated with MI in a sample of 582 cases and 630 controls from the Etude Cas-Témoin sur l'Infarctus du Myocarde. Detailed haplotype analysis confirmed the protective effect of the P715 allele but additionally revealed that the presence of two asparagine codons at sites S290N and N562D was associated with a higher risk of MI, consistenly in France and Northern Ireland, but only when they were carried by the same haplotype. This finding illustrates the complexity of the relationship between gene variability and disease and the necessity to explore in detail the polymorphisms of candidate genes.