RAPSN (receptor associated protein of the synapse) encodes a postsynaptic protein essential for clustering nicotinic acetylcholine receptors at the neuromuscular junction 1. The protein functions as a structural component that links acetylcholine receptors to the underlying postsynaptic cytoskeleton, facilitating proper neuromuscular transmission 2. RAPSN mutations cause congenital myasthenic syndrome type 11, characterized by impaired neuromuscular signal transmission 23. Clinically, RAPSN variants present with limb-girdle weakness patterns and are among the most common causes of congenital myasthenic syndromes 24. Notably, RAPSN patients show a distinctive clinical course with severe manifestations in early childhood (54.8% requiring intensive care) but subsequent improvement in adulthood 4. The gene maps to chromosome 11.2-p11.1 1. RAPSN mutations can also cause lethal fetal akinesia deformation sequence, representing the severe end of the phenotypic spectrum 5. Importantly, most RAPSN-associated conditions respond favorably to treatments that enhance neuromuscular transmission, including acetylcholinesterase inhibitors and other pharmacological interventions 24.