Genetics and neuropsychology: A merger whose time has come

Enough vs. More: Neuropsychological testing is more useful than genetic testing in the baseline evaluation of Parkinson disease

In conclusion, baseline neuropsychological testing provides a vast amount of unique cognitive, psychiatric, behavioral, and psychosocial information that is useful to individuals with PD, care partners, and treatment team providers. As a baseline examination, it provides opportunities for comparison purposes in the future, a prediction of risk assessment and future treatment needs, and at the time of evaluation for clinical treatment to improve quality of life. Such information is not captured by genetic testing, although the ideal path moving forward would be to perform both neuropsychological testing and genetic testing at baseline.

Vitamin B-12 malabsorption and renal function are critical considerations in studies of folate and vitamin B-12 interactions in cognitive performance: NHANES 2011-2014

BACKGROUND

Cognitive health is a public health concern among older adults. Dietary supplement (SUP) use is common and concerns have been raised about high folic acid intake among those with vitamin B-12 deficiency and exacerbation of poor cognitive performance (PCP).

OBJECTIVES

We evaluated SUP use, usual folic acid intake, and blood folate and vitamin B-12 concentrations in relation to cognitive performance.

METHODS

We used NHANES 2011-2014 data on adults aged ≥60 y (n = 2867) and estimated total usual folic acid intake from diet and supplements, vitamin B-12 intake from SUPs, blood folates, vitamin B-12 concentrations, vitamin B-12 insufficiency (≤258 pmol/L), high folate (serum folate ≥59 nmol/L or RBC folate ≥1609 nmol/L), and PCP (<34 on the Digit Symbol Substitution Test). We assessed folate distributions adjusted for multiple variables, including renal function.

RESULTS

Compared with persons without PCP, adults with PCP were less likely to use supplements containing folic acid (mean ± SEE: 34.4% ± 2.4%) or vitamin B-12 (mean ± SEE: 47.5% ± 1.6%). Among vitamin B-12-insufficient adults, 18.0% ± 1.6% (mean ± SEE) reported taking a vitamin B-12 supplement. Among participants with high folate and insufficient vitamin B-12 concentrations, 34.3% ± 11.5% (mean ± SEE) reported taking vitamin B-12-containing supplements. Persons with high folate and normal vitamin B-12 concentrations had lower odds of PCP [aOR (adjusted odds ratio): 0.61; 95% CI: 0.45, 0.83] than persons with normal folate and vitamin B-12. Persons with high folate and normal methylmalonic acid (MMA) had lower odds of PCP (OR: 0.56; 95% CI: 0.40, 0.78) than those with normal folate and MMA concentrations. After adjustment for renal function, elevated risk of PCP was attenuated among persons with high folate and MMA. Concurrent high folate and insufficient vitamin B-12 concentrations were not associated with PCP.

CONCLUSIONS

Differential associations between vitamin B-12 and MMA highlight the need to consider renal function in studies of high folate and low vitamin B-12 status. Consumption of vitamin B-12 supplements concurrent with low vitamin B-12 status may indicate vitamin B-12 malabsorption.

Neuropsicologia Clínica: Notas Históricas, Fundamentos Teórico-Metodológicos e Diretrizes para Formação Profissional

Resumo A Neuropsicologia se concentra em disciplinas oriundas da interface entre a neurociência e a psicologia cognitiva, e sua pesquisa converge da relação entre o cérebro e o comportamento. Como se tem observado em diversos centros de referência no Brasil, a difusão da Neuropsicologia vem ocorrendo de maneira vertiginosa, embora o estabelecimento de diretrizes de educação e treinamento ainda se encontrem despadronizados. O presente artigo descreve o desenvolvimento histórico da Neuropsicologia, enfocando seus fundamentos teóricos e metodológicos, sua condição regulatória atual, além de perspectivas futuras na criação de diretrizes para capacitação profissional. Pesquisas vêm demonstrando uma tendência em caracterizar a atividade do neuropsicólogo nos mais diversos locais nos quais a neuropsicologia é ensinada, praticada e difundida. No Brasil, faz-se necessária uma taxonomia acerca do ofício do profissional especialista em neuropsicologia, seja em relação à sua formação ou sua atuação profissional.

Clinical and Genetic Risk Prediction of Cognitive Impairment After Blood or Marrow Transplantation for Hematologic Malignancy

PURPOSE

Using a candidate gene approach, we tested the hypothesis that individual single nucleotide polymorphisms (SNPs) and gene-level variants are associated with cognitive impairment in patients with hematologic malignancies treated with blood or marrow transplantation (BMT) and that inclusion of these SNPs improves risk prediction beyond that offered by clinical and demographic characteristics.

PATIENTS AND METHODS

In the discovery cohort, BMT recipients underwent a standardized battery of neuropsychological tests pre-BMT and at 6 months, 1 year, 2 years, and 3 years post-BMT. Associations between 68 candidate genes and cognitive impairment were assessed using generalized estimating equation models. Elastic-Net regression was used to build Base (sociodemographic), Clinical, and Combined (Base plus Clinical plus genetic) risk prediction models of post-BMT impairment. An independent nonoverlapping cohort from the BMT Survivor Study with self-report of learning/memory problems (as identified by their health care provider) was used for model replication.

RESULTS

The discovery cohort included 277 participants (58.5% males; 68.6% non-Hispanic whites; and 46.6% allogeneic BMT recipients). Adjusting for BMT type, age at BMT, sex, race/ethnicity, and cognitive reserve, SNPs in the blood-brain barrier, telomere homeostasis, and DNA repair genes were significantly associated with cognitive impairment. Compared with the Clinical Model, the Combined Model had higher predictive power in both the discovery cohort (mean area under the receiver operating characteristic curve [AUC], 0.89; 95% CI, 0.85 to 0.93 v 0.77; 95% CI, 0.71 to 0.83; P = 1.24 × 10^-9) and the replication cohort (AUC, 0.71; 95% CI, 0.66 to 0.76 v 0.63; 95% CI, 0.57 to 0.68; P = .004).

CONCLUSION

Inclusion of candidate genetic variants enhanced the prediction of risk of post-BMT cognitive impairment beyond that offered by demographic/clinical characteristics and represents a step toward a personalized approach to managing patients at high risk for cognitive impairment after BMT.

Genetic and Environmental Influences on Verbal Fluency in Middle Age: A Longitudinal Twin Study

Mounting evidence suggests that measures of phonemic fluency and semantic fluency are differentially associated with other cognitive and health phenotypes, but few studies have examined their shared and unique variance, especially using genetically-informative designs. In this study, 1464 middle-aged twins completed six fluency subtests at up to two time-points (mean age 56 and 62 years). Confirmatory factor analyses supported a two-factor solution: a General Fluency latent factor explained variation in all six subtests and a Semantic-Specific factor accounted for additional variance in semantic subtests. Both factors were explained primarily by genetic influences at both waves (a2 = 0.57-0.76). There was considerable stability of individual differences over 6 years (r = .90 for General Fluency, r = .81 for Semantic-Specific), especially for genetic influences (rg = .94 and 1.0, respectively). These results suggest that semantic fluency can be viewed as a combination of general and semantic-specific variance, but phonemic fluency is captured entirely by the general factor.

The Epigenetic Basis of Individuality

This commentary reviews the concept of experience-dependent epigenetic modifications in the CNS as a core mechanism underlying individuality and individuation at the behavioral level. I use the term individuation to refer to the underlying neurobiological processes that result in individuality, with the discussion focusing on individuality of cognitive, emotional, and behavioral repertoire. The review describes recent work supporting the concept of neuroepigenetic mechanisms underlying individuation, possible roles of transgenerational effects, and implications for precision medicine.

Novel functional variants at the GWAS-implicated loci might confer risk to major depressive disorder, bipolar affective disorder and schizophrenia

BACKGROUND

A challenge of understanding the mechanisms underlying cognition including neurodevelopmental and neuropsychiatric disorders is mainly given by the potential severity of cognitive disorders for the quality of life and their prevalence. However, the field has been focused predominantly on protein coding variation until recently. Given the importance of tightly controlled gene expression for normal brain function, the goal of the study was to assess the functional variation including non-coding variation in human genome that is likely to play an important role in cognitive functions. To this end, we organized and utilized available genome-wide datasets from genomic, transcriptomic and association studies into a comprehensive data corpus. We focused on genomic regions that are enriched in regulatory activity-overlapping transcriptional factor binding regions and repurpose our data collection especially for identification of the regulatory SNPs (rSNPs) that showed associations both with allele-specific binding and allele-specific expression. We matched these rSNPs to the nearby and distant targeted genes and then selected the variants that could implicate the etiology of cognitive disorders according to Genome-Wide Association Studies (GWAS). Next, we use DeSeq 2.0 package to test the differences in the expression of the certain targeted genes between the controls and the patients that were diagnosed bipolar affective disorder and schizophrenia. Finally, we assess the potential biological role for identified drivers of cognition using DAVID and GeneMANIA.

RESULTS

As a result, we selected fourteen regulatory SNPs locating within the loci, implicated from GWAS for cognitive disorders with six of the variants unreported previously. Grouping of the targeted genes according to biological functions revealed the involvement of processes such as 'posttranscriptional regulation of gene expression', 'neuron differentiation', 'neuron projection development', 'regulation of cell cycle process' and 'protein catabolic processes'. We identified four rSNP-targeted genes that showed differential expression between patient and control groups depending on brain region: NRAS-in schizophrenia cohort, CDC25B, DDX21 and NUCKS1-in bipolar disorder cohort.

CONCLUSIONS

Overall, our findings are likely to provide the keys for unraveling the mechanisms that underlie cognitive functions including major depressive disorder, bipolar disorder and schizophrenia etiopathogenesis.

Epigenetics, nutrition and mental health. Is there a relationship?

Many aspects of human development and disease are influenced by the interaction between genetic and environmental factors. Understanding how our genes respond to the environment is central to managing health and disease, and is one of the major contemporary challenges in human genetics. Various epigenetic processes affect chromosome structure and accessibility of deoxyribonucleic acid (DNA) to the enzymatic machinery that leads to expression of genes. One important epigenetic mechanism that appears to underlie the interaction between environmental factors, including diet, and our genome, is chemical modification of the DNA. The best understood of these modifications is methylation of cytosine residues in DNA. It is now recognized that the pattern of methylated cytosines throughout our genomes (the 'methylome') can change during development and in response to environmental cues, often with profound effects on gene expression. Many dietary constituents may indirectly influence genomic pathways that methylate DNA, and there is evidence for biochemical links between nutritional quality and mental health. Deficiency of both macro- and micronutrients has been associated with increased behavioural problems, and nutritional supplementation has proven efficacious in treatment of certain neuropsychiatric disorders. In this review we examine evidence from the fields of nutrition, developmental biology, and mental health that supports dietary impacts on epigenetic processes, particularly DNA methylation. We then consider whether such processes could underlie the demonstrated efficacy of dietary supplementation in treatment of mental disorders, and whether targeted manipulation of DNA methylation patterns using controlled dietary supplementation may be of wider clinical value.