ArticlebioRxiv : the preprint server for biology2026
Brain B Vitamin Status and One-Carbon Metabolism Gene Polymorphisms are Associated with Cognitive Impairment in Alzheimer's and Parkinson's Disease.
Article in bioRxiv : the preprint server for biology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
Abstract
Introduction: Disturbances in one-carbon metabolism and homocysteine (Hcy) regulation have been implicated in Alzheimer's disease (AD) and Parkinson's disease (PD), yet direct evidence from human brain tissue and the contribution of genetic variation remain limited. We investigated whether B-vitamin-related metabolic deficits and polymorphisms in one-carbon metabolism pathways contribute to cognitive impairment in AD and PD. Methods: We quantitated metabolites related to B vitamins and one-carbon metabolism in post-mortem frontal cortex (n=136) and putamen (n=68) from clinically and neuropathologically characterized healthy controls, AD dementia (AD-D), PD with dementia (PD-D), PD with mild cognitive impairment (PD-MCI), and cognitively normal PD (PD-CN). Genotyping targeted variants related to one-carbon metabolism and B vitamins. Multivariable regression models controlled for demographic, clinical, metabolic, and tissue-handling covariates. Results: AD-D and PD-D shared a convergent cortical signature of reduced biotin, pyridoxal-5'-phosphate, thiamine monophosphate, pantothenic acid, and betaine. Elevated Hcy and reduced tetrahydrofolate were specific to AD-D and to PD-D during acute levodopa exposure. PD-MCI exhibited deficits in putamen resembling cortical dementia-associated changes. Self-reported B-vitamin supplementation attenuated several abnormalities, including complete normalization of levodopa-associated Hcy and folate disturbances in PD-D. Across subjects, multiple B vitamins showed strong associations with Hcy and betaine, indicating coordinated impairment of all three Hcy-metabolizing pathways. Genotyping analysis identified polymorphisms in MTRR, TYMS, MTR, NFE2L2, BHMT, and MTHFR that were differentially distributed across cognitive subgroups or associated with AD-related pathology scores. Composite genetic and metabolic burden scores were elevated in cognitively impaired groups but not in cognitively normal groups. Conclusion: Dementia in AD and PD is characterized by convergent B-vitamin deficiencies and genetic susceptibilities that disrupt Hcy metabolism. These findings provide a mechanistic explanation for levodopa-related Hcy accumulation in vulnerable PD subjects and identify B-vitamin supplementation as a potentially modifiable factor relevant to cognitive decline.
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.