A comparison of neuropsychological performance between US and Russia: preparing for a global clinical trial.

BACKGROUND: Understanding regional differences in cognitive performance is important for interpretation of data from large multinational clinical trials. METHODS: Data from Durham and Cabarrus Counties in North Carolina, USA and Tomsk, Russia (n = 2972) were evaluated. The Montreal Cognitive Assessment (MoCA), Trail Making Test Part B (Trails B), Consortium to Establish a Registry for Alzheimer's Disease Word List Memory Test (WLM) delayed recall, and self-report Alzheimer's Disease Cooperative Studies Mail-In Cognitive Function Screening Instrument (MCFSI) were administered at each site. Multilevel modeling measured the variance explained by site and predictors of cognitive performance. RESULTS: Site differences accounted for 11% of the variation in the MoCA, 1.6% in Trails B, 1.7% in WLM, and 0.8% in MCFSI scores. Prior memory testing was significantly associated with WLM. Diabetes and stroke were significantly associated with Trails B and MCFSI. CONCLUSIONS: Sources of variation include cultural differences, health conditions, and exposure to test stimuli. Findings highlight the importance of local norms to interpret test performance.

A New Leu714Arg Variant in the Converter Domain of MYH7 is Associated with a Severe Form of Familial Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy is the most frequent autosomal dominant disease, yet due to genetic heterogeneity, incomplete penetrance, and phenotype variability, the prognosis of the disease course in pathogenic variant carriers remains an issue. Identifying common patterns among the effects of different genetic variants is important. METHODS: We investigated the cause of familial hypertrophic cardiomyopathy (HCM) in a family with two patients suffering from a particularly severe disease. Searching for the genetic variants in HCM genes was performed using different sequencing methods. RESULTS: A new missense variant, p.Leu714Arg, was identified in exon 19 of the beta-myosin heavy chain gene (MYH7). The mutation was found in a region that encodes the 'converter domain' in the globular myosin head. This domain is essential for the conformational change of myosin during ATP cleavage and contraction cycle. Most reports on different mutations in this region describe severe phenotypic consequences. The two patients with the p.Leu714Arg mutation had heart failure early in life and died from HCM complications. CONCLUSIONS: This case presents a new likely pathogenic variant in MYH7 and supports the hypothesis that myosin converter mutations constitute a subclass of HCM mutations with a poor prognosis for the patient.

Association and Gene-Gene Interactions Study of Late-Onset Alzheimer's Disease in the Russian Population.

Alzheimer's disease (AD) is a neurodegenerative disorder, and represents the most common cause of dementia. In this study, we performed several different analyses to detect loci involved in development of the late onset AD in the Russian population. DNA samples from 472 unrelated subjects were genotyped for 63 SNPs using iPLEX Assay and real-time PCR. We identified five genetic loci that were significantly associated with LOAD risk for the Russian population (TOMM40 rs2075650, APOE rs429358 and rs769449, NECTIN rs6857, APOE ε4). The results of the analysis based on comparison of the haplotype frequencies showed two risk haplotypes and one protective haplotype. The GMDR analysis demonstrated three significant models as a result: a one-factor, a two-factor and a three-factor model. A protein-protein interaction network with three subnetworks was formed for the 24 proteins. Eight proteins with a large number of interactions are identified: APOE, SORL1, APOC1, CD33, CLU, TOMM40, CNTNAP2 and CACNA1C. The present study confirms the importance of the APOE-TOMM40 locus as the main risk locus of development and progress of LOAD in the Russian population. Association analysis and bioinformatics approaches detected interactions both at the association level of single SNPs and at the level of genes and proteins.

Healthy aging and preclinical dementia: the United States-Israel Longitudinal Database project.

This article proposes the establishment of a United States-Israel Longitudinal Database for Healthy Aging and Preclinical Dementia as a prototype model for the eventual creation of an international database. It is envisioned that such a comprehensive international database, as a shared research resource, will provide the foundation for a systems approach to solve the dual public health problems of: (1) Early detection of individuals at an elevated risk of developing Alzheimer's disease, and (2) Developing interventions to delay onset of, or prevent, chronic brain disorders later in life.

Frequencies of alleles, genotypes and haplotypes of two polymorphisms in the clusterin gene in the Russian elderly population categorized by cognitive performance.

This article contains data on the frequencies of alleles, genotypes and haplotypes of the single nucleotide polymorphisms (SNPs) rs2279590 and rs1532278 in the CLU gene in a cohort of normal elderly from the Russian population. The SNPs have been reported to be associated with Alzheimer's disease and cognitive functions in genome-wide and candidate genes association studies. Cognitive performance in sample set was estimated by the Montreal Cognitive Assessment (MoCA). The frequencies of alleles, genotypes and haplotypes of two SNPs were calculated in 3 groups: total sample set, sample set with MoCA score less than 21 (the first quartile) and group with MoCA score more than 24 (the fourth quartile).

Analysis of Association of Genetic Markers in the LUZP2 and FBXO40 Genes with the Normal Variability in Cognitive Performance in the Elderly.

Cognitive performance is an important endophenotype for various neurodegenerative and neuropsychiatric traits. In the present study two genetic variants in the leucine-zipper protein (LUZP2) and the F-box 40 protein (FBXO40) genes, previously reported to be genome-wide significant for Alzheimer's diseases and schizophrenia, were examined for an association with cognitive abilities in normal elderly from the Russian population. Rs1021261 in the LUZP2 and rs3772130 in the FBXO40 were genotyped by multiplex PCR and MALDI-TOF mass spectrometry in a sample of 708 normal elderly subjects tested for cognitive performance using the Montreal Cognitive Assessment (MoCA). Association of genetic variability with the MoCA scores was estimated by parametric and nonparametric analysis of variance and by the frequency comparison between upper and lower quartiles of MoCA distribution. Significantly higher frequency of "TT" genotype of rs1021261 in the LUZP2 gene as well as "A" allele and "AA" genotype of rs3772130 in the FBXO40 gene was found in a subsample of individuals with the MoCA score less than 20 comparing to the fourth quartile's subsample (MoCA > 25). The data of the present study suggests that genetic variability in the LUZP2 and FBXO40 loci associated with neurodegenerative and neuropsychiatric diseases is also contributed to the normal variability in cognitive performance in the elderly.

Genetic Variants in CSMD1 Gene Are Associated with Cognitive Performance in Normal Elderly Population.

Recently, genetic markers rs10503253 and rs2616984 in the CUB and Sushi multiple domains-1 (CSMD1) gene have been reported to be associated with schizophrenia and cognitive functions in genome-wide association studies. We examined the associations of the above SNPs with cognitive performance evaluated by the Montreal Cognitive Assessment (MoCA) tool in a cohort of the normal elderly from the Russian population. Significant association of rs2616984 genotypes with the MoCA scores was found using nonparametric analysis. No association of rs10503253 with MoCA scores was observed using both parametric and nonparametric statistics. Significant combined effect of two-locus CSMD1 genotypes on MoCA scores was demonstrated by median test. Allele "A" and genotype "AA" of rs2616984 were significantly associated with the lower MoCA scores in comparison of 1st and 4th quartiles of MoCA total score distribution. The results suggest that genetic variants in CSMD1 gene are likely a part of genetic component of cognitive performance in the elderly.

Syntropy, genetic testing and personalized medicine.

The concept of syntropic diseases was proposed at the beginning of the last century to emphasize the phenomenon of nonrandom co-occurrence of human disorders. Common genes underlying specific syntropic diseases were called syntropic genes. The application of this concept to contemporary genomic studies will facilitate the understanding of the molecular basis of complex diseases, provide future direction for discovering new targets for therapy and prognosis, and may even lead to the reassessment of disease classification for the practice of more precise personalized medicine. With the acceptance of the syntropic genes theory, new genetic tests, focused on markers pointing to a set of pathogenetically linked diseases rather than to a single nosology, can be developed.

An epidemiologic-based survey of public attitudes towards predictive genetic testing in Russia.

Many new genetic tests for common multifactorial disorders are becoming available to individuals, including direct-to-consumer genotyping services. Typically, studies of public attitudes reveal a high level of interest for individual genotyping. In a Russian urban population, 85% of 2000 respondents answered positively to a question about their own willingness to undergo predictive genetic testing for preventable health conditions. Gender, age and health status significantly influenced response. Multivariate discriminant analyses revealed that wanting to know about probable future diseases, readiness to improve lifestyles and an interest in learning about individual genome characteristics are the most important predictors for wanting to be tested. Along with the high level of interest, highly overestimated expectations were encountered in many studies. With the low predictive abilities of currently available genetic tests for common disorders, proper interpretation of the data and genetic counseling are essential. There is a need for prospective validation of genetic panels for risk assessments, and for efforts to measure the effects of genetic information disclosure and how this information might contribute to lifestyle changes.

Public interest and expectations concerning commercial genotyping and genetic risk assessment.

In contrast to the modest progress made in the interpretation and clinical application of genomic data, genotyping technologies have experienced great progress. Genotyping costs are progressively decreasing making individual genotyping more commonly available. Financial availability of individual genome analysis and the strong desire of many people to know about their individual genomic characteristics, promotes the marketing of genetic tests of variable predictive value directly to the public. A survey of 2000 Russian respondents revealed very positive attitudes and beliefs towards these genetic developments: 85% of surveyed individuals would like to have their genetic risk for avoidable diseases estimated, and 89% responded stating that they would try to change their lifestyle by giving up bad habits, following a recommended diet or taking medications if a high risk of disease was identified. It is believed that with time, validated genetic information will find its rightful place in medicine, by supplementing phenotypic clinical data with validated genetic interpretations.

Global pharmacogenetics: genetic substructure of Eurasian populations and its effect on variants of drug-metabolizing enzymes.

AIMS: To study the frequency distribution of cytochrome P450 (CYP) functional genetic variants in five Eurasian populations from the territory of Siberia in Russia. MATERIALS & METHODS: Unrelated healthy Tuvinians, Buryats, Altaians, Yakuts and Russians (n = 87-88) were genotyped for CYP2C9*2, CYP2C9*3, CYP2C19*2, CYP2C19*3, CYP3A5*3 and CYP3A5*6. Standard pairwise genetic distances, locus-specific and global Fst statistics were calculated. RESULTS: CYP allele and genotype frequencies demonstrated significant variability. Overall, the degree of between-population variance displayed by CYP SNPs was lower than that recorded from neutral short tandem repeats and Alu-insertion polymorphism, indicating evolutionary conservation of CYP polymorphisms. CYP-based genetic distances were well correlated with the geographic distances across populations (r = 0.822, p = 0.008). CONCLUSIONS: Although the tested variants were present in the neighboring, yet secluded, populations at the expected range of frequencies, the observed frequencies were significantly variable across Eurasian populations, indicating potential relevance to clinical decision making.