Table 2. Abnormal histone modifications and associated diseases.

Stage	Disease	Aetiology	Species	Reference
Spermatogenesis	Decrease of spermatocytes	The reduction of histone H3K4 methyltransferase MII2 activity	Mouse	Glaser et al.[69]
	Sperm apoptosis and sterility	The loss of LSD1/KDM1	Human	Shi et al.[70]
	Impaired post meiotic chromatin condensation	Deficiency of the JHMD2A can down regulate the expression of two genes, the P1 and TNP1, leading to the condensation and proper packaging of the chromatin failure in sperms	Mouse	Najafipour et al.[71]
	Inhibit the process of spermatogenesis	Altered dimethylation states of the H3K9	Mouse	Xiong et al.[74]
	Nucleosome removal abnormality	Deficiency of the RNF8, a ubiquitin ligase, could lead to the abnormal H4K16 acetylation that significantly suppresses the histone removal and results in the incorporation of the transition protein	Mouse	Lu et al.[72]
	Partial failure in chromatin condensation, abnormal sperm head morphology, immotility of epididymal sperm, and male infertility	Knockout Chd5, a gene encoding chromatin-remodeling nuclear protein, decreases the H4 hyperacetylation in elongating spermatids	Mouse	Zhuang et al.[73]
Embryogenesis	Insufficient sperm chromatin compaction that persists in the zygote	Aberrant acetylation of the H4K12 in promoters of the development of important genes	Human	Paradowska et al.[75]
	Less developmentally competent embryos	abnormal expression of BRG1 and KDM1A around the period of embryonic genome activation could alter the H3K4 methylation	Porcine	Glanzneret al.[76]
	Peri-implantation lethality	Absence of the ERG-associated protein with the SET domain, a histone methyltransferase that specifically trimethylates the H3K9 residue	Mouse	Dodge et al.[77]
Birth	Rubinstein-Taybi syndrome	Acetylation of histones alters the folding of the chromatin nucleoprotein complex	Human	Ausio et al.[78]