Lysine specific demethylase 1 (LSD1, also known as KDM1A), is a histone modifying enzyme recruited by transcription factors to specific regions in the genome. LSD1 forms part of complexes that regulate the expression of genes involved in the onset and progression of diseases such as cancer, CNS disorders, viral infections, and others.

LSD1 primarily removes methyl groups from mono and dimethylated lysine 4 in the histone H3 tail, thus acting as an “eraser”. LSD1 also acts as a scaffolding protein for other components of the multiprotein complexes needed to control transcription.