COLQ encodes the collagen-like tail subunit of asymmetric acetylcholinesterase, which anchors catalytic acetylcholinesterase subunits to the synaptic basal membrane at neuromuscular junctions 1. This protein functions as a structural component that localizes acetylcholinesterase to the synaptic cleft, where it degrades acetylcholine and terminates cholinergic synaptic transmission 2. COLQ contains collagen-like domains that enable its integration into the extracellular matrix of the synaptic basal lamina, positioning acetylcholinesterase optimally for efficient neurotransmitter clearance. Mutations in COLQ cause congenital myasthenic syndrome type 5 (CMS5), characterized by impaired neuromuscular transmission due to defective acetylcholine breakdown 13. CMS5 patients typically present with muscle weakness, fatigability, and may require intensive care in severe cases 4. The syndrome shows variable disease progression, with some patients experiencing stability while others may have progressive worsening throughout life 4. COLQ mutations represent one of the synaptic basal lamina defects causing CMS, accounting for approximately 4.5% of CMS cases in some populations 5. Treatment typically involves acetylcholinesterase inhibitors and other neuromuscular transmission enhancing medications 2.