摘要:

The involuntary collection of DNA into databanks for insurance and identification purposes has been well-explored, as has the voluntary use of such repositories of DNA information for the construction of databases for medical research. There is a little-investigated fourth manifestation of such databanks, however, a voluntary, non-medical, consumer-oriented one. Specifically, DNA information is now being marketed in the commodity consumer market as a way of establishing both genealogical relatedness and identityper se, including religious, racial, and ethnic identity. In this article the development of such identity databases is discussed, and the ethical consequences of the accumulation and dissemination of such information are briefly explored.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Genetic diversity contributes to both disease susceptibility and variability in response to drugs. However, it has proven difficult to isolate genes that underlie common complex disease, and genetic variations that influence clinical responses to drugs remain largely uncovered. The candidate gene approach to uncover genetic variations that contribute to disease susceptibility or variations in response to common drugs has not met expectations. Although the sib-pair linkage approach has certain theoretical advantages in dealing with common/complex disease, success has been slow in coming. Meanwhile family studies including siblings, cousins and second cousins, and studies in well-defined founder populations, have increasingly gained popularity and enabled scientists to map and isolate genes for common complex disease, such as schizophrenia and asthma. The latter method has generated new hope that this approach may also be effective in mapping genes that regulate drug response. Indeed, there is compelling evidence that corticosteroid sensitivity is a mapable trait in patients with asthma. Collectively, these studies support the value of leveraging information available within population-based data systems to map and isolate genes for common complex disease and drug response.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Attention deficit-hyperactivity disorder (ADHD) is a very common and heterogeneous childhood-onset psychiatric disorder, affecting between 3% and 5% of school age children worldwide. Although the neurobiology of ADHD is not completely understood, imbalances in both dopaminergic and noradrenergic systems have been implicated in the origin and persistence of core symptoms, which include inattention, hyperactivity, and impulsivity. The role of a genetic component in its etiology is strongly supported by genetic studies, and several investigations have suggested that the dopamine transporter gene (DAT1;SLC6A3locus) may be a small-effect susceptibility gene for ADHD.Stimulant medication has a well-documented efficacy in reducing ADHD symptoms. Methylphenidate, the most prescribed stimulant, seems to act mainly by inhibiting the dopamine transporter protein and dopamine reuptake. In fact, its effect is probably related to an increase in extracellular levels of dopamine, especially in brain regions enriched in this protein (i.e. striatum). It is also important to note that dopamine transporter densities seem to be particularly elevated in the brain of ADHD patients, decreasing after treatment with methylphenidate. Altogether, these observations suggest that the dopamine transporter does play a major role in ADHD.Among the several polymorphisms already described in theSLC6A3locus, a 40 bp variable number of tandem repeats (VNTR) polymorphism has been extensively investigated in association studies with ADHD. Although there are some negative results, the findings from these reports indicate the allele with ten copies of the 40 bp sequence (10-repeat allele) as the risk allele for ADHD. Some investigations have suggested that this polymorphism can be implicated in dopamine transporter gene expressionin vitroand dopamine transporter densityin vivo, even though it is located in a non-coding region of theSLC6A3locus. Despite all these data, few studies have addressed the relationship between genetic markers (specifically the VNTR) at theSLC6A3locus and response to methylphenidate in ADHD patients. A significant effect of the 40 bp VNTR on response to methylphenidate has been detected in most of these reports. However, the findings are inconsistent regarding both the allele (or genotype) involved and the direction of this influence (better or worse response). Thus, further investigations are required to determine if genetic variation due to the VNTR in the dopamine transporter gene is able to predict different levels of clinical response and palatability to methylphenidate in patients with ADHD, and how this information would be useful in clinical practice.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder characterized by hyperandrogenism and chronic anovulation. The syndrome is frequently associated with an increased risk for insulin resistance and type 2 diabetes mellitus; obesity exacerbates insulin resistance and favors the progression from impaired glucose tolerance to diabetes in these patients. In young women, precocious pubarche and hyperinsulinemia are early manifestations of PCOS.The familial clustering of women with PCOS suggests that heredity is implicated in the origin of the syndrome. However, genetic approaches to its pathogenesis have been hampered by the heterogeneity of phenotypic features within families, and the lack of uniform criteria for diagnosis.Currently, PCOS is considered a polygenic trait that might result from the interaction of susceptibility and protective genomic variants under the influence of environmental factors. Both linkage analysis and association studies are valid tools for the study of the genetics of PCOS.Candidate genes for PCOS include those related to androgenic pathways and metabolic associations of the syndrome. More recently, genes encoding inflammatory cytokines have been identified as target genes for PCOS, as proinflammatory genotypes and phenotypes are also associated with obesity, insulin resistance, type 2 diabetes, PCOS, and increased cardiovascular risk.This paper reviews the candidate genes involved in the metabolic pathways that are altered in patients with PCOS. Despite a significant amount of research in this area, none of the genes studied so far has been identified as the PCOS susceptibility gene for the majority of cases. PCOS is the first component of the metabolic syndrome to be detected in many women, so the identification and correct diagnosis of PCOS has important preventive and therapeutic implications for the affected women and their families. In the future, new therapeutic approaches to PCOS will rely on knowing the genes, environmental influences, and etiologic mechanisms associated with the disorder.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Autoinflammatory diseases are defined as illnesses caused by primary dysfunction of the innate immune system. This new concept includes a broad number of disorders, but the spotlight has been focused for the past two years on periodic fevers (familial Mediterranean fever [FMF]; mevalonate kinase deficiency [MVK]; tumor necrosis factor [TNF] receptor-associated periodic syndrome [TRAPS]; cryopyrin-associated periodic syndrome [CAPS]), Crohn’s disease and Blau syndrome, thanks to the recent understanding of their molecular basis. Indeed, until recently, these conditions were defined only by phenotypical features, the main ones being recurrent attacks of fever, abdominal pain, arthritis, and cutaneous signs, which sometimes overlap, obscuring diagnosis. The search for distinguishing signs such as periorbital edema in TRAPS, and the use of specific functional tests where available, are valuable. Needless to say, molecular screening of the causative genes has dramatically improved patient quality-of-life by providing early and accurate diagnosis, subsequently allowing for the appropriate treatment. Some patients, however, remain hard to manage despite the advent of new genetic tests, and/or due to the lack of effective treatment.The original clinical link between the aforementioned diseases can now be confirmed by a molecular one, following the exciting discovery that most of the altered proteins are related to the death domain fold (DDF) superfamily involved in inflammation and apoptosis. These molecules mediate the regulation of nuclear factor-kappa B (NF-κB) activation, cell apoptosis, and interleukin-1β secretion through cross-regulated and, sometimes, common signaling pathways. Knowledge of the defective step in autoinflammation has already led to the elucidation of the mechanisms of action of existing drugs and may allow the development of new therapies.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Background and objectivesA number of recent studies surveying single nucleotide polymorphisms within the exonic regions of human genes have revealed a significant number of such variants, including many non-synonymous variants. This highlights the need to directly identify, within individual clinically well-defined patients, those variants that alter protein function as well as structure. We report on the development of a novel phenotypic screening process that combines high-throughput molecular cloning techniques with functional expression utilizing the cell-based assay R-SAT.MethodsWe applied the phenotypic screening process to an analysis of the m1 muscarinic acetylcholine receptor (CHRM1) gene in a cohort of 74 individuals, including 48 diagnosed with neurodegenerative disease, primarily Alzheimer disease, who have been stratified according to their clinical response to the acetylcholinesterase inhibitor donepezil. Phenotypic screening of theCHRM1gene involved PCR-based amplification from genomic DNA and heterologous expression in mammalian cells.ResultsPhenotypic screening yielded functional responses to the agonist carbachol displaying a mean potency (−pEC50± standard deviation) of 5.8 ± 0.2, which did not differ from that observed with expression of the wild-type receptor gene (6.0 ± 0.3). No altered levels of constitutive receptor activity were observed. Dideoxy sequencing did not reveal any non-synonymous variants in the coding exon of this gene within this clinical cohort, while detecting three synonymous variants.ConclusionThe results confirm that the m1 receptor gene (CHRM1) is not highly polymorphic in the human population, suggesting that genetic variation within the coding exon of this gene is not a contributing factor to the clinical variability observed during treatment of dementia with cholinergic enhancement therapies.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

IntroductionThe hybridization intensities derived from microarray experiments, for example Affymetrix’s MAS5 signals, are very often transformed in one way or another before statistical models are fitted. The motivation for performing transformation is usually to satisfy the model assumptions such as normality and homogeneity in variance. Generally speaking, two types of strategies are often applied to microarray data depending on the analysis need: correlation analysis where all the gene intensities on the array are considered simultaneously, and gene-by-gene ANOVA where each gene is analyzed individually.AimWe investigate the distributional properties of the Affymetrix GeneChip®signal data under the two scenarios, focusing on the impact of analyzing the data at an inappropriate scale.MethodsThe Box-Cox type of transformation is first investigated for the strategy of pooling genes. The commonly used log-transformation is particularly applied for comparison purposes. For the scenario where analysis is on a gene-by-gene basis, the model assumptions such as normality are explored. The impact of using a wrong scale is illustrated by log-transformation and quartic-root transformation.ResultsWhen all the genes on the array are considered together, the dependent relationship between the expression and its variation level can be satisfactorily removed by Box-Cox transformation. When genes are analyzed individually, the distributional properties of the intensities are shown to be gene dependent. Derivation and simulation show that some loss of power is incurred when a wrong scale is used, but due to the robustness of thet-test, the loss is acceptable when the fold-change is not very large.

ISSN:1175-2203    

出版商:ADIS    

年代:2004

数据来源: ADIS