Table 1.

Developmental disorders resulting from disruption of epigenetic mechanisms (Galaburda 2005)

Mechanism	Disease	Gene	Effect	Consequences
DNA methylation	Rett syndrome	MeCP2	Hypermethylation, abnormal mRNA splicing	Transcription repression or activation
	Fragile X syndrome	FMR1	Promoter hypermethylation	Transcription repression
	Prader Willi syndrome/Angelman syndrome	del15q11-q13, UBE3A	Aberrant methylation in imprint control region	Transcription repression or activation
	Immunodeficiency, centromere instability, facial dysmorphism	DNMT3B	Hypomethylation	Transcription activation
	Alzheimer disease	NEP	CpG island hypomethylation	Transcription activation
Histone acetylation	Rubenstein-Taybi syndrome	CBP (HAT)	Reduced histone acetylation, hypertrimethylation of DNA	Transcription repression
	Coffin-Lowry syndrome	RSK32	Hypophosphorylation of site H3S10	Increased transcription of MAP kinase genes
	Oculofaciocardio-dental	BCOR	Disruption of HDACs	Transcription activation
Histone methylation	Sotos syndrome	NSD1	Decreased methylation of sites H4K20, H3K36	Transcription activation of multiple genes
	Kleefstra syndrome	EHMT1	Decreased histone methylation	Transcription activation
	Huntington Disease	HTT	Increased methylation at site H3K9 and possibly H3K27	Transcription activation

Galaburda (2005) adapted from Portela and Esteller (2010); Day and Sweatt (2011); Kelly et al. (2010), Lagali et al. (2010); and Gropman and Batshaw (2010)