GDE1 is a 331 amino acid multi-pass membrane protein that localizes to both the membrane and the cytoplasm and contains one GDPD domain. Expressed in a wide variety of tissues, GDE1 uses magnesium as a cofactor to catalyze the conversion of 1-(sn-glycero-3-phospho)-1D-myo-inositol to myo-inositol and sn-glycerol 3-phosphate, an event that is modulated by G protein signaling pathways and provides a link between phosphoinositide metabolism and G protein signal transduction. The gene encoding GDE1 maps to human chromosome 16, which encodes over 900 genes and comprises nearly 3% of the human genome. The GAN gene is located on chromosome 16 and, with mutation, may lead to giant axonal neuropathy, a nervous system disorder characterized by increasing malfunction with growth. The rare disorder Rubinstein-Taybi syndrome is also associated with chromosome 16, as is Crohn's disease, which is a gastrointestinal inflammatory condition.