MDGA1 (MAM domain containing glycosylphosphatidylinositol anchor 1) is a GPI-anchored cell adhesion molecule critical for cortical development and synaptic organization. During forebrain development, MDGA1 exhibits layer- and area-specific expression patterns in the neocortex, serving as a marker for cortical lamination and patterning 1. The protein functions to aggregate and maintain basal progenitors within the subventricular zone, a process essential for their proliferation and generation of cortical layer neurons 2. MDGA1 contains immunoglobulin and MAM domains that enhance cell-cell adhesion while reducing adhesion to extracellular matrix proteins, increasing cell motility 3. At the synapse, MDGA1 localizes to inhibitory synapses where it may regulate Neuroligin-2 function and influence GABAergic synapse formation 4. Functionally, MDGA1 knockout mice exhibit memory deficits and altered synaptic excitation/inhibition balance 5, though acute deletion does not substantially impair hippocampal synaptic transmission in young mice. Clinically, MDGA1 variants associate with schizophrenia and bipolar disorder risk in Chinese populations 6, while elevated MDGA1 promoter methylation correlates with idiopathic restless legs syndrome, particularly in familial cases 7. Common missense variants showed no association with restless legs syndrome in Caucasian populations 8.