LNPK (lunapark) is an endoplasmic reticulum (ER)-shaping membrane protein that stabilizes nascent three-way junctions within the ER tubular network 1. As a curvature-stabilizing protein, LNPK localizes to and maintains ER three-way junctions by antagonizing the small GTPase Atlastin 2. The protein possesses intrinsic ubiquitin ligase activity in its N-terminal region, which is required for proper ER junction localization 2. Beyond ER morphology, LNPK functions in sequestering misassembled nucleoporins at ER foci to maintain nuclear pore complex function 3. Clinically, biallelic loss-of-function LNPK variants cause autosomal recessive neurodevelopmental disorder with epilepsy and corpus callosum hypoplasia 41. Affected individuals present with moderate-to-profound developmental delay, cognitive impairment, refractory epilepsy, and progressive neurodegeneration with characteristic 'ear-of-the-lynx' sign on brain imaging—signal alterations of the forceps minor 4. Additional features include cerebellar hypoplasia/atrophy and substantia nigra signal changes 45. During neurodevelopment, LNPK is critical for interneuron migration; LNPK deletion impairs ER displacement along the leading neuronal branch, resulting in abnormal migration 6. The disease mechanism likely involves ER-phagy dysfunction related to perturbed ER morphology.