A 16-year-old Chinese girl suffered for 9 years with periodic high fevers above 39°C, cold-triggered urticaria, and pain in multiple joints. It was previously misdiagnosed with recurrent infections and juvenile idiopathic arthritis. Laboratory tests showed elevated levels of interleukin-6 (IL-6) and acute phase reactants, a lymph node biopsy confirmed necrotizing lymphadenitis. Whole-exome sequencing revealed a heterozygous NLRP12 variant p.Glu619Gln, classified as a variant of undetermined significance with no previous clinical cases. After treatment with baricitinib at a dose of 2 mg daily, there was rapid relief of symptoms within 2 weeks, IL-6 levels decreased from 17.8 pg/ml to 2.1 pg/ml, and clinical control persisted for 12 months. This is the first reported case of NLRP12-AID autoinflammatory disease with this variant.