Polyhydramnios, megalencephaly, symptomatic epilepsy (PMSE) is a severe human developmental and epileptic syndrome caused by a homozygous partial deletion in the STRAD-alpha gene (LYK5), truncating 180 C-terminal residues of the protein. Individuals affected by this condition suffer from severe mental retardation, gross movement disorders, and childhood mortality. Severe intractable epilepsy and megalencephaly are characteristic.
