Biomedical subjects

Dennis van der Meer

Publications and source records attributed to Dennis van der Meer.

4 recordsLinked to original sources

PubMed2026

Causal Effects Between Neurodegenerative Diseases, Metabolites, and Brain Volume.

INTRODUCTION/OBJECTIVE: Neurodegenerative diseases such as Alzheimer's disease (AD), Lewy dody dementia (LBD), and Parkinson's disease (PD) are linked to changes in brain volume. However, causal evidence on how these diseases affect brain volume and whether metabolites mediate these causal effects remains limited. METHODS: We applied mediation Mendelian randomization analysis using GWAS summary statistics. The inverse variance-weighted method was used to assess causal effects and identify potential metabolite mediators. RESULTS: The MR analyses indicated that bilateral thalamus and putamen volumes (FDR < 0.05) had causal effects on PD. AD and LBD showed causal effects on bilateral thalamus and hippocampus (FDR < 0.01), with LBD specifically showing a causal effect on bilateral putamen (FDR < 0.05). Mediation analyses revealed that AD had a genetically predicted association with Nervonoy- L-carnitine and 1-linoleoyl-2-arachidonoyl-GPC (p-value = 0.04 and 0.01, respectively). Moreover, Nervonoy-L-carnitine was suggestively negatively associated with hippocampus volume (p-value = 0.03 and 0.02, respectively). 1-linoleoyl-2-arachidonoyl-GPC exhibited a negative genetically predicted association with hippocampus volume (p-value < 0.05). Additionally, LBD showed a negative genetically predicted association on the ratio of retinol to linoleoyl-arachidonoyl- glycerol (p-value = 0.02), and a positive genetically predicted association on Nervonoy-L-- carnitine (p-value < 0.05) and 1-linoleoyl-2-arachidonoyl-GPC (p-value = 0.03). DISCUSSION: These results suggest that AD and LBD affect brain regions through causal pathways. The involvement of specific metabolites highlights potential mechanisms linking neurodegeneration to brain volume. CONCLUSION: Nervonoylcarnitine and 1-linoleoyl-2-arachidonoyl-GPC may mediate the predicted effects of AD and LBD on hippocampal volumes, while the ratio of retinol to linoleoyl-arachidonoyl- glycerol mediates only LBD.

Humans↗

PubMed2025

A genome-wide analysis of the shared genetic risk architecture of complex neurological and psychiatric disorders.

Although neurological and psychiatric disorders have historically been considered to reflect distinct pathogenic entities, recent findings suggest shared pathophysiological mechanisms. However, the extent to which these heritable disorders share genetic influences remains unclear. Here we performed a comprehensive analysis of genome-wide association study data, involving nearly 1 million cases across ten neurological diseases and ten psychiatric disorders, to compare their common genetic signal and biological associations. Using complementary statistical tools, we demonstrate that a large set of common genetic variants impacts the risk of multiple neurological and psychiatric disorders, even in the absence of genetic correlations. Furthermore, genome-wide association studies on psychiatric disorders consistently implicate neuronal biology, whereas neurological diseases are associated with diverse neurobiological processes. Together, this study elucidates the genetic relationship between complex neurological and psychiatric disorders, indicating a larger degree of genetic pleiotropy than previously recognized. The findings have implications for disease classification, precision medicine and clinical practice.

Humans↗

PubMed2025

Mapping Cerebellar Morphology in 15q11.2 CNV Carriers Using Normative Modeling.

Copy number variations (CNVs) at the 15q11.2 locus of the human genome have been associated with altered brain structure and increased risk for neurodevelopmental and neuropsychiatric disorders. The cerebellum is increasingly seen as a crucial brain region for neurodevelopmental conditions, yet the effects of 15q11.2 CNVs on cerebellar morphology remain largely unclear. Importantly, 15q11.2 CNVs shows reduced or incomplete penetrance (meaning that not all CNV carriers are affected) and variable expressivity (meaning that symptoms may differ between individuals with the same genetic alteration). Thus, there is a need to not only assess group differences, but also to quantify anatomical variability at the individual level. Here, we address these issues using normative models of brain anatomy trained on large datasets (n > 52k, age range: 3-85) to assess both group and individual-level deviations in cerebellar anatomy in carriers of 15q11.2 deletions (n = 120, mean [SD] age= 64.95 [7.58]) and duplications (n = 149, mean [SD] age=64.31 [7.21]), compared to non-carriers (n = 19,028, mean [SD] age=64.31 [7.58]). Group-level case-control analyses revealed significantly smaller total and regional cerebellar volumes in both deletion and duplication carriers, though with small effect sizes. Individual-level deviation analyses, capturing pronounced alterations in specific individuals, revealed a heterogeneous pattern among carriers. Overall, our findings suggest that CNVs at the 15q11.2 locus exert modest and highly individualized effects on cerebellar morphology.

15q11.2↗

PubMed2021

1q21.1 distal copy number variants are associated with cerebral and cognitive alterations in humans.

Low-frequency 1q21.1 distal deletion and duplication copy number variant (CNV) carriers are predisposed to multiple neurodevelopmental disorders, including schizophrenia, autism and intellectual disability. Human carriers display a high prevalence of micro- and macrocephaly in deletion and duplication carriers, respectively. The underlying brain structural diversity remains largely unknown. We systematically called CNVs in 38 cohorts from the large-scale ENIGMA-CNV collaboration and the UK Biobank and identified 28 1q21.1 distal deletion and 22 duplication carriers and 37,088 non-carriers (48% male) derived from 15 distinct magnetic resonance imaging scanner sites. With standardized methods, we compared subcortical and cortical brain measures (all) and cognitive performance (UK Biobank only) between carrier groups also testing for mediation of brain structure on cognition. We identified positive dosage effects of copy number on intracranial volume (ICV) and total cortical surface area, with the largest effects in frontal and cingulate cortices, and negative dosage effects on caudate and hippocampal volumes. The carriers displayed distinct cognitive deficit profiles in cognitive tasks from the UK Biobank with intermediate decreases in duplication carriers and somewhat larger in deletion carriers-the latter potentially mediated by ICV or cortical surface area. These results shed light on pathobiological mechanisms of neurodevelopmental disorders, by demonstrating gene dose effect on specific brain structures and effect on cognitive function.

Brain↗