EPM2A encodes the glucan phosphatase laforin, a type of dual specificity phosphatase, and EPM2B encodes malin, an E3-ubiquitin ligase (PMID: 22364389). Laforin is encoded by the 130 Kb four-exon gene EPM2A on chromosome 6q24 of the human genome. It is ubiquitously expressed in all tissues, although brain, skeletal muscle, heart and liver have higher levels of expression (PMID: 9931343). Laforin has also been shown to interact with other regulatory subunits of PP1, including GL and R6, members of the same family as protein targeting to glycogen (PTG) (PMID: 27702709). In the brain, laforin is expressed predominantly in cerebellum, hippocampus, frontal cortex and olfactory bulb. Laforin expression increases after birth, reaching a maximum during the adulthood (PMID: 11355878). EPM2A alternative splicing results in two laforin isoforms that are identical from amino acid 1-309, but contain a divergent C-terminal domain. Isoform laforin-331 is the most abundant form, possesses phosphatase activity, and when overexpressed in cell culture localizes to the cytoplasm and ER (PMID: 18617530).