SUV39H1

The encoded protein is a histone methyltransferase that trimethylates lysine 9 of histone H3, resulting in transcriptional gene silencing and heterochromatin formation at pericentric and telomeric regions. Mutations cause an autosomal dominant neurodevelopmental disorder characterized by intellectual disability, developmental delay, and behavioral abnormalities. This gene is highly constrained against loss-of-function variants (pLI = 0.99), indicating that haploinsufficiency is likely not tolerated in the general population.