Table 2.

Summary of Human and Mouse In Vivo Findings at Different Levels of EZH2 Activity

Genotype	Mouse Phenotype	Human Phenotype	Predicted Relative Enzyme Activity (%)
Homozygous null	Embryonic lethal (16)	DECIPHER: one 12.26-Mb homozygous deletion found with intellectual disability, abnormal facies, seizures, etc.	0
Homozygous Weaver mutation	Perinatal lethal (current study)	Not described	∼30 (speculated based on current study)
Heterozygous null	Decreased live births (16)	DECIPHER: various heterozygous deletions found, with a variety of anomalies. No loss-of-function variants found in ExAC, suggesting decreased fitness phenotype	50
Heterozygous Weaver mutation	Born at normal ratio, mild regrowth	Weaver syndrome: overgrowth, advanced bone maturation, intellectual disability, etc.	∼65 (assumes mutant has 30% activity)

DECIPHER refers to findings in the database found at https://decipher.sanger.ac.uk/. ExAC refers to findings in the database found at http://exac.broadinstitute.org/.