Skip to main content

Advertisement

Table 1 Epigenetic studies using discordant MZ twins*

From: Epigenetics of discordant monozygotic twins: implications for disease

Phenotype Assay Tissue (cell heterogeneity correction) Major findings Identification cohort Validation/ replication References
Adolescent depression Illumina 450 K Buccal cells (no correction) Two differentially methylated positions reproducible in brain 18 discordant pairs of MZ twins Validation: bisulfite pyrosequencing [[67]]
Alzheimer’s disease Immunohistochemistry for 5-methylcytosine Temporal neocortex (no correction) Significantly reduced levels of DNA methylation 1 discordant MZ twin pair   [[68]]
Autism spectrum disorders Custom array§ Lymphoblastoid cells (no correction) 73 differentially methylated CpG islands 3 pairs of male discordant MZ twin pairs Validation: bisulfite sequencing and methylation-specific PCR [[69]]
Autism spectrum disorders Illumina 27 K Whole blood (no correction) Differentially methylated regions in genes already mentioned in the literature 34 discordant and 5 concordant MZ twin pairs for ASD or a related trait Validation: bisulfite pyrosequencing [[70]]
Bipolar disorder Illumina 27 K Whole blood (no correction) Hypomethylation in the upstream region of GPR24 11 discordant MZ twin pairs   [[71]]
Bipolar disorder MS-RDA Lymphoblastoid cells (no correction) Hypomethylation of PPIEL 1 discordant MZ twin pair, 23 unrelated cases, and 18 unrelated controls Validation: bisulfite pyrosequencing [[72]]
Birth weight Illumina 450 K Saliva (correction for buccal epithelium and leukocyte subtypes) 45 differentially methylated CpG sites 17 discordant monochorionic MZ female twin pairs Validation: bisulfite sequencing [[60]]
Breast cancer Illumina 450 K Whole blood (no correction) DOK7 as a candidate for blood-based cancer diagnosis 15 discordant MZ twin pairs Validation: bisulfite pyrosequencing of 21 discordant MZ twin pairs [[73]]
Caudal duplication anomaly Targeted bisulfite sequencing PBMCs and buccal cells (no correction) Hypermethylation of the AXIN1 promoter in PBMCs, but not in buccal epithelia 1 discordant MZ twin pair   [[74]]
Childhood leukemia and secondary thyroid carcinoma Targeted bisulfite pyrosequencing Primary skin fibroblasts (no correction) Increased methylation of BRCA1 1 discordant MZ twin pair   [[75]]
Congenital renal agenesis RRBS Whole blood (no correction) 514 DMRs in 25 genes, including 6 related to organ development 1 discordant MZ twin pair   [[76]]
Major depressive disorder MeDIP-seq Whole blood (correction for lymphocytes, monocytes, neutrophils, and eosinophils) Hypermethylation of a region within the ZBTBT20 gene 50 discordant MZ twin pairs Replication: MeDIP-seq in 356 unrelated case–control samples [[77]]
Major psychosis Illumina 27 K Whole blood (no correction) Hypomethylation in the promoter region of ST6GALNAC1 22 discordant MZ twin pairs Replication: EpiTYPER in 45 post-mortem brain samples [[71]]
Multiple sclerosis RRBS CD4+ lymphocytes (no correction) No reproducible differences were detected 3 discordant MZ twin pairs   [[78]]
Pain sensitivity MeDIP-seq Whole blood (correction for lymphocytes, monocytes, neutrophils, and eosinophils) Significant association signal in the promoter of the gene TRPA1 25 discordant MZ twin pairs Replication: MeDIP-seq in 50 unrelated samples. Validation: bisulfite pyrosequencing and Illumina 450 k [[79]]
Psoriasis Illumina 27 K CD4+ and CD8+ cells (no correction) Correlation between DNA methylation differences and gene expression differences of genes involved in the immune response only in CD4+ CD4+: 17 discordant MZ twins pair; CD8+: 13 discordant MZ twins pairs   [[80]]
Schizophrenia Illumina 27 K Whole blood (no correction) Hypermethylation in the upstream region of PUS3 11 discordant MZ twin pairs   [[71]]
Schizophrenia Targeted bisulfite sequencing Lymphocytes (no correction) Patterns of methylation in the 5'-regulatory region of DRD2 gene are closer between affected individuals 1 discordant and 1 concordant MZ twin pair   [[81]]
Systemic lupus erythematosus Illumina GoldenGate Methylation Cancer Panel I White blood cells (no correction) 49 differentially methylated genes potentially relevant in autoimmune inflammatory diseases processes 5 discordant MZ twin pairs Validation: bisulfite sequencing [[82]]
Type 1 diabetes Illumina 27 K CD14+ monocytes (no correction) 132 differentially methylated CpG sites 15 discordant MZ pairs Validation: bisulfite pyrosequencing. Replication: Illumina 27 K of 4 twin pairs [[17]]
Type 1 diabetes Illumina 27 K Immortalized B cell lines (no correction) 88 differentially methylated CpG sites 3 discordant and 6 concordant MZ twin pairs Validation: bisulfite sequencing [[83]]
Ulcerative colitis Illumina 27 K and MeDIP-chip Intestinal biopsies (no correction) 61 disease-associated genes 10 discordant MZ pairs Validation: bisulfite pyrosequencing [[84]]
  1. *Abbreviations: ASD, autism spectrum disorders; DMR, differentially methylated region; MeDIP-chip, methylated DNA immunoprecipitation and array hybridization (Nimblegen custom 385 k Tiling Arrays in [[84]]); MS-RDA, methylation-sensitive representational difference analysis; MZ, monozygotic; PBMC, peripheral blood mononuclear cell; RRBS, reduced representation bisulfite sequencing.
  2. Tissue or cell sample used at discovery stage; cell heterogeneity correction approach is given in parentheses if relevant.
  3. Effect sizes are described in the text.
  4. §8.1 K CpG island microarrays (UHN Microarray Centre).