Genome-wide methylation analysis of early-onset schizophrenia

Area of Science:

• Neuroscience
• Genetics
• Epigenetics

Background:

• Schizophrenia (SCZ) is a severe mental disorder with a complex genetic basis.
• The age of onset in SCZ may indicate underlying genetic vulnerability.
• Epigenetic mechanisms, particularly DNA methylation, have been underexplored in relation to SCZ onset.

Purpose of the Study:

• To investigate the association between DNA methylation patterns and the age of onset in schizophrenia.
• To identify specific DNA methylation sites (CpG sites) correlated with early or late onset of SCZ.

Main Methods:

• Genome-wide DNA methylation was quantified in 138 SCZ patients using the Illumina Infinium HumanMethylation450 BeadChip array.
• Analysis explored differential methylation in CpG sites and regions associated with age of onset, controlling for age, sex, and white blood cell composition.
• Both binary (early vs. late onset) and continuous analyses were performed.

Main Results:

• Binary analysis identified four intergenic CpG sites on chromosome 2 associated with early-onset SCZ, with cg10392614 hypermethylation being the strongest predictor.
• Continuous analysis highlighted cg11723066 (linked to JAM3) as the top CpG site, with hypomethylation associated with earlier onset, though results did not reach statistical significance.
• The identified CpG sites were primarily intergenic.

Conclusions:

• DNA methylation plays a potential role in determining the age of onset for schizophrenia.
• Specific DNA methylation patterns may serve as biomarkers for early detection or prediction of SCZ onset.
• Investigating DNA methylation in first-episode psychosis populations can enhance understanding of SCZ's epigenetic underpinnings.