Table 2 Methylation studies in monozygotic (MZ) twins discordant for personality and disease
Study | Condition | Method | Tissue | MZ pairs, n | Results |
|---|---|---|---|---|---|
Weksberg et al. [83] | Beckwith-Wiedemann syndrome | Southern blotting with DMR probes (H19, KvDMR1, SNRP) | Lymphocytes and fibroblasts | 10 | Loss of methylation at KvDMR1 in all probands |
Petronis et al. [91] | Schizophrenia | Bis-seq (DRD2) | Lymphocytes | 1 | Discordance confirmed |
Mill et al. [92] | Attention deficit hyperactivity disorder | Bis-seq (COMT) | Buccal epithelial cells | 12 | 0.1 to 52.3% discordance |
Oates et al. [93] | Caudal duplication | Bis-seq (AXIN1) | PBMC | 1 | Discordance confirmed |
Kuratomi et al. [95] | Bipolar disorder | MS-RDA | Lymphoblastoid cell lines | 1 | 4 DMRs, 1 candidate gene |
Kaminsky et al. [94] | Risk-taking behavior | MEDIP-chip | PBMC | 1 | 38 DMRs, 1 candidate gene |
Mastroeni et al. [32] | Alzheimer disease | Immunohistochemistry | Temporal neocortex | 1 | Discordance confirmed |
Javierre et al. [96] | Systemic lupus erythematosus | MEDIP-chip | White blood cells | 5 | 49 DMRs, 8 candidate genes |
Wong et al. [87] | ADHD, depression, antisocial behavior | Quantitative high-throughput mass spectrometry (DRD4, SERT, MAOA) | Buccal epithelial cells | 46 | Discordance confirmed |
Baranzini et al. [72] | Multiple sclerosis | RRBS | CD4+ lymphocytes | 3 | 2-178 DMRs, no candidate |
Hu et al. [98] | Autism | MEDIP-chip | Lymphoblastoid cell lines | 3 | 73 DMRs, 2 candidate genes |
Tierling et al. [118] | Beckwith-Wiedemann syndrome | Bis-seq (11 DMR) | Peripheral blood cells, buccal epithelial cells, skin fibroblasts, saliva | 1 | Hypomethylation at KvDMR1 |
Harder et al. [119] | Optic glioma | Bis-seq (NF1) | Leukocytes | 8 | Discordance confirmed |
Souren et al. [120] | BMI | Bis-seq | Saliva | 8 | Small discordance identified, not correlated with BMI discordance |
Rakyan et al. [90] | Type 1 diabetes | Illumina Array | CD14+ cells | 15 (+9 healthy control) | 132 methylation variable positions |
Dempster et al. [99] | Schizophrenia/Bipolar disorder | Illumina Array | Whole blood | 22 | Disease-associated DMRs, including ST6GALNAC1 as the top candidate |
Galetzka et al. [82] | Childhood leukemia/secondary thyroid carcinoma | Bis-seq (6 tumor suppressors) | Skin fibroblasts | 1 | Increased BRCA1 methylation |
Gervin et al. [100] | Psoriasis | Illumina Array | CD4+ and CD8+ cells | 27 | No significant methylation difference. Significant correlation between some DMRs and psoriasis-associated gene expression differences |