UNASSIGNED: Essential tremor (ET) is a neurological syndrome of unknown origin with poorly understood etiology and pathogenesis. It is suggested that the cerebellum and its tracts may be involved in the pathophysiology of ET. DNA methylome interrogation of cerebellar tissue may help shine some light on the understanding of the mechanism of the development of ET. Our study used postmortem human cerebellum tissue samples collected from 12 ET patients and 11 matched non-ET controls for DNA methylome study to identify differentially methylated genes in ET.
UNASSIGNED: Using Nugen\'s Ovation reduced representation bisulfite sequencing (RRBS), we identified 753 genes encompassing 938 CpG sites with significant differences in DNA methylation between the ET and the control group. Identified genes were further analyzed with Ingenuity Pathway Analysis (IPA) by which we identified certain significant pathways, upstream regulators, diseases and functions, and networks associated with ET.
UNASSIGNED: Our study provides evidence that there are significant differences in DNA methylation patterns between the ET and control samples, suggesting that the methylation alteration of certain genes in the cerebellum may be associated with ET pathogenesis. The identified genes allude to the GABAergic hypothesis which supports the notation that ET is a neurodegenerative disease, particularly involving the cerebellum.

Epigenetic changes may occur in response to environmental stressors, and an altered epigenome pattern may represent a stable signature of environmental exposure.
Here, we examined the potential of DNA methylation changes in 910 prediagnostic peripheral blood samples as a marker of exposure to tobacco smoke in a large multinational cohort.
We identified 748 CpG sites that were differentially methylated between smokers and nonsmokers, among which we identified novel regionally clustered CpGs associated with active smoking. Importantly, we found a marked reversibility of methylation changes after smoking cessation, although specific genes remained differentially methylated up to 22 years after cessation.
Our study has comprehensively cataloged the smoking-associated DNA methylation alterations and showed that these alterations are reversible after smoking cessation.