The aim of this study was to examine whether the well-established effect of the common TaqIB polymorphism in intron 1 of the gene for cholesterol ester transfer protein (CETP) on high density lipoprotein cholesterol (HDL-C) concentration and increased risk of myocardial infarction (MI), could be explained by the recently identified -629C>A functional polymorphism in the promoter. Non-fatal MI cases (388 male) and a control group of 794 healthy men were recruited from the 30 year long prospective Reykjavik Study. In the healthy men the frequency of the TaqIB B2 allele was 0.47 (95% CI: 0.44-0.50) and there was a strong allelic association with the -629A allele (D=-0.21, P
The A1 allele of TaqI A restriction fragment length polymorphism (RFLP) in the D2 receptor (DRD2) gene locus has been suggested to be associated with low D2 receptor density in man. Striatal dopamine transporter (DAT) densities were studied with [(123)I]2-beta-carbometoxy-3beta(4-iodophenyl)tropane and single-photon emission tomography in 29 detoxified alcoholics, who were also genotyped for the two alleles of TaqI A RFLP at the DRD2 receptor gene locus. Alcoholics with the A1/A2 genotypes (n = 10) had statistically significantly higher DAT densities than subjects with the A2/A2 genotypes [n = 19; 8.0 +/- 1.2 (mean +/- SD) vs 6.9 +/- 1.1, P = 0.035]. We suggest that the TaqI A RFLP is in linkage disequilibrium with a gene variant modifying DAT density in alcoholics.
This study examined whether the Trp64Arg mutation in the beta3-adrenergic receptor (beta3AR) and the A-->G mutation in the uncoupling protein-1 (UCP-1) genes have associations with weight loss and subsequent weight maintenance. Seventy-seven obese (body mass index range, 29-46 kg/m2), clinically healthy, premenopausal women were studied. A 12-wk weight reduction by very low calorie diet (VLCD) was followed by a 40-wk weight maintenance phase. The subjects were divided into four groups according to their beta3AR and UCP-1 genotype: no mutation (control; n=37), only Trp64Arg mutation in the beta3AR gene (n=12), only A-->G mutation in the UCP-1 gene (n=23), and both mutations (n=5). Subjects with both mutations had a lower weight reduction during VLCD than the controls [-10.5+/-0.6 (+/-SEM) vs. -14.0+/-0.5 kg; P=0.051, by ANOVA]. During the maintenance phase, weight in subjects with both mutations increased by 5.8+/-1.5 kg, but remained unchanged in the controls (-0.5+/-0.8 kg; P=0.041). The changes in weight in subjects with only one of the mutation were close to the results in the controls. Resting energy expenditure, adjusted for fat mass, fat-free mass, and maximal aerobic power, did not change differently between the groups throughout the study. The results suggest that a combination of the Trp64Arg mutation in the beta3AR and the A-->G mutation in the UCP-1 genes may be associated with faster weight gain after a VLCD.
Depression disorders are a clinically heterogeneous disease group. Their development is to a substantial extent underlain by dysfunction of the serotonin system, in particular, disturbed serotonin transport. The heterogeneity of depressions is associated, among other factors, with the age at disease onset. Allele polymorphism of the serotonin transporter (5-HTT) gene was tested for association with age at disease onset, clinical signs, and anxiety-related traits of depression patients. A sample included 77 patients (mean age 61.2 +/- 8.8 years) with late-onset depression (LOD, mean age at onset 56.58 +/- 9.7 years) and 74 patients (mean age 31.0 +/- 11.8 years) with early-onset depression (EOD, mean age at onset 23.9 +/- 7.4 years). In genotype frequency distribution of two 5-HTT gene polymorphism, the LOD and EOD groups did not differ from each other (chi 2 = 0.33, P = 0.85 for VNTR-17; chi 2 = 3.33, P = 0.19 for HTTLPR) and from a control group (chi 2 = 0.34, P = 0.84 for VNTR-17; chi 2 = 2.1, P = 0.35 for HTTLPR). In either group, patients differing in VNTR-17 and HTTLPR genotypes did not differ in psychological traits and, in particular, in anxiety-related traits. In the case of the HTTLPR polymorphism, LOD patients with genotype ss tended to display less severe neuroticism (t = 2.03, P = 0.0507) and scored significantly less on the Hamilton depression scale (t = 2.19, P = 0.039). Thus, the 5-HTT gene polymorphisms do not affect the risk of depression but is possibly associated with specific clinical signs of the disease, at least in elderly patients.
Recent evidence has implicated the genes for 5-lipoxygenase activating protein (ALOX5AP) and phosphodiesterase 4D (PDE4D) as susceptibility genes for stroke in the Icelandic population. The aim of the present study was to explore the role of these genes in a central European population of stroke patients.
A total of 639 consecutive stroke patients and 736 unrelated population-based controls that had been matched for age and sex were examined using a case-control design. Twenty-two single-nucleotide polymorphisms (SNPs) covering ALOX5AP were genotyped. For PDE4D, microsatellite AC008818-1 and 12 SNPs, which tag all common haplotypes in previously identified linkage disequilibrium (LD) blocks, were analyzed.
A nominally significant association with stroke was observed with several SNPs from ALOX5AP, including SNP SG13S114, which had been part of the Icelandic at-risk haplotype. Associations were stronger in males than in females, with SG13S114 (odds ratio, 1.24; 95% CI, 1.04 to 1.55; P=0.017) and SG13S100 (odds ratio, 1.26; 95% CI 1.03 to 1.54; P=0.024) showing the strongest associations. No significant associations were detected with single markers and haplotypes in PDE4D. The frequencies of single-marker alleles and haplotypes differed largely from those in the Icelandic population.
The present study suggests that sequence variants in the ALOX5AP gene are significantly associated with stroke, particularly in males. Variants in the PDE4D gene are not a major risk factor for stroke in individuals from central Europe. Population differences in allele and haplotype frequencies as well as LD structure may contribute to the observed differences between populations.
Tylosis with esophageal cancer (TOC) is a rare familial cancer syndrome inherited in an autosomal-dominant manner and characterized by esophageal cancer susceptibility and hyperkeratotic skin lesions. Two heterozygous missense mutations in the RHBDF2 gene were recently reported to be associated with TOC in three families: a p.Ile186Thr mutation was found in families from the UK and the US and a p.Pro189Leu mutation was detected in a German TOC family. We aimed to validate these novel results in an independent material by screening RHBDF2 in a previously unreported Finnish TOC family. We identified a new missense mutation, p.Asp188Asn, segregating with TOC in the Finnish family, and interestingly the detected mutation alters a codon located between the two previously reported mutation sites. Thus, we confirmed RHBDF2 mutations as the underlying cause of the TOC syndrome and our results suggest that the TOC associated mutations might be specific for this particular site in the RHBDF2 gene. These results enable the genetic counseling and diagnostic mutation screening of the members of TOC families.
Several cold-hardy grasses have been shown to have ice-binding proteins (IBPs) that protect against freeze-thaw injury. Here, we looked for IBP activity in an Alaskan coastal grass, Leymus mollis (Pooidae), that had not previously been examined. Rhizome tissue had strong ice-structuring and ice recrystallization inhibiting (IRI) activities, indicating the probable presence of IBPs. The gene sequence of an IBP was obtained. The sequence encoded a 118-amino acid IRI domain composed of eight repeats and that was 80% identical to the IRI domain of the IBP of perennial ryegrass Lolium perenne. The predicted 3D structure of the IRI domain had eight beta-roll coils like those in L. perenne IBP.
The orphan receptor APJ and its recently identified endogenous ligand, apelin, exhibit high levels of mRNA expression in the heart. However, the functional importance of apelin in the cardiovascular system is not known. In isolated perfused rat hearts, infusion of apelin (0.01 to 10 nmol/L) induced a dose-dependent positive inotropic effect (EC50: 33.1+/-1.5 pmol/L). Moreover, preload-induced increase in dP/dt(max) was significantly augmented (P
The Keewatin Inuit of the Northwest Territories of Canada have a very low age-adjusted mortality rate from coronary heart disease. We hypothesized that this apparent protection from disease has a genetic basis. We determined the prevalence of the disease-associated alleles of five candidate genes for atherosclerosis-related phenotypes. Surprisingly, four of the five alleles studied, namely AGT T235, FABP2 T54, PON R192 and APOE E4, were significantly more frequent in a sample of 175 Keewatin Inuit than among a representative control sample of whites living in the region. The high frequencies of these disease-associated alleles suggests either that they have no relationship with disease susceptibility in the Inuit, or that some unmeasured genetic and/or environmental factors mitigate disease susceptibility that is associated with these alleles. This highlights the difficulty in extrapolating findings from one population to another. Also, very modest genotype-phenotype associations were observed between APOE genotype (P = 0.016) and plasma low-density lipoprotein cholesterol concentration and between FABP2 genotype and plasma 2-h postprandial, glucose concentration (P = 0.048). The relationship between APOE alleles and plasma low-density lipoprotein cholesterol was the same as has been previously reported in many study samples. However, the relationship between FABP2 alleles and plasma 2-h postprandial glucose concentrations was the opposite to that reported in other studies. This suggests that differences in environment, such as the type of fatty acid consumed, interacts with functional differences in gene products involved in candidate metabolic pathways to produce phenotypic differences.
A common 44-base pair insertion/deletion polymorphism in the promoter region of the human serotonin transporter (5-HTT) gene has been observed to be associated with affective illness and anxiety-related traits. This biallelic functional polymorphism, designated long (L) and short (S), affects 5-HTT gene expression since the S promoter is less active than the L promoter. Since there is strong evidence of a disturbance in brain serotonergic transmission among antisocial, impulsive, and violent type 2 alcoholic subjects, we decided to test the hypothesis that the frequency of the S allele, which is associated with reduced 5-HTT gene expression, is higher among habitually violent type 2 alcoholics when compared with race and gender-matched healthy controls and non-violent late-onset (type 1) alcoholics. The 5-HTT promoter genotype was determined by a PCR-based method in 114 late onset (type 1) non-violent alcoholics, 51 impulsive violent recidivistic offenders with early onset alcoholism (type 2), and 54 healthy controls. All index subjects and controls were white Caucasian males of Finnish origin. The S allele frequency was higher among type 2 alcoholics compared with type 1 alcoholics (chi2 = 4.86, P = 0.028) and healthy controls (chi2 = 8.24, P = 0.004). The odds ratio for SS genotype vs LL genotype was 3.90, 95% Cl 1.37-11.11, P = 0.011 when type 2 alcoholics were compared with healthy controls. The results suggest that the 5-HTT 'S' promoter polymorphism is associated with an increased risk for early onset alcoholism associated with antisocial personality disorder and impulsive, habitually violent behavior.