Evidence map›Paper›PMID 16172806›Full record

SynthesisJournal of human genetics2005

The role of G196A polymorphism in the brain-derived neurotrophic factor gene in the cause of Parkinson's disease: a meta-analysis.

Elias Zintzaras, Georgios M Hadjigeorgiou

Open access · bronzeAbstract readComparative StudyMeta-Analysis
PubMed Publisher
In one paragraph

Synthesis in Journal of human genetics, 2005. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 22 papers, 7 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
22citing papers in PubMed, 7 pooled it
2.0field-weighted citation impact, top 14% of its field
1 · What the graph read from it

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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

22 citing papers in PubMed, 7 syntheses or guidelines pooled it, 66 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Pooled it
  4. Association between BDNF G196A (Val66Met) polymorphism and cognitive impairment in patients with Parkinson's disease: a meta-analysis.Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologica · 2019
    Pooled it
  5. The role of MTHFR gene in multiple myeloma.Journal of human genetics · 2008
    Pooled it
  6. Pooled it
  7. Pooled it
  8. Frontiers in neurology · 2022
    Article
  9. Review
  10. Article
  11. Review
  12. Article
  13. Article
  14. Review
  15. Critical Issues inFrontiers in molecular neuroscience · 2018
    Review
  16. Risk Factor Genes in Patients with Dystonia: A Comprehensive Review.Tremor and other hyperkinetic movements (New York, N.Y.) · 2018
    Review
  17. Review
  18. Review
  19. Review
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors at 1 institution in 1 country.

Elias ZintzarasDepartment of Biomathematics, University of Thessaly School of Medicine, Papakyriazi 22, 41222, Larissa, Greece. zintza@med.uth.gr.
Georgios M HadjigeorgiouNeurogenetics Unit, Department of Neurology, University Hospital of Larissa, University of Thessaly School of Medicine, Papakyriazi 22, 41222, Larissa, Greece.
University of Thessaly · GR

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The association between Parkinson's disease (PD) and the G196A polymorphism in the brain-derived neurotrophic factor (BDNF) gene has been investigated in several case-control studies, producing contradictory results: one study indicated that homozygocity of AA is associated with PD, another study produced the opposite result, whereas other studies found no association. To investigate these contradictory findings, a meta-analysis of all available association studies between the G196A polymorphism and the risk of developing PD was conducted. Four out of six identified studies included populations of East Asian descent, and two included populations of European descent (Whites). Overall, the meta-analysis of the allele contrast (A vs G) suggested large heterogeneity between studies (P=0.07, I2 =51%) and no association between G196A and the risk of developing PD: random effects odds ratio (OR)=1.00 [95% CI (0.85, 1.18)]. The sensitivity analysis (exclusion of two studies: one East Asian and one White) with the controls not in Hardy-Weinberg equilibrium showed large heterogeneity (P=0.10, I2 =52%) and no significant association: random effects OR=0.94 [95% CI (0.77, 1.15)]. The subgroup analyses for East Asians and Whites produced no significant association. In addition, the contrast of homozygotes, and the dominant and recessive models for allele A did not support a major role for this polymorphism in the pathogenesis of PD. There were no sources of bias in the selected studies, and the differential magnitude of effect in large vs small studies was not significant. The meta-analysis results suggest that the involvement of the BDNF gene in susceptibility to PD merits further exploration with larger and more rigorous population association studies.

Indexed as

Asian PeopleBrain-Derived Neurotrophic FactorGenetic Predisposition to DiseaseHumansInheritance PatternsOdds RatioParkinson DiseasePolymorphism, Single NucleotideSensitivity and SpecificityWhite PeopleBrain-Derived Neurotrophic Factor

Identifiers

PMID16172806
OpenAlexW2117622145

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

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.