BTG3 and connective tissue disorder: As a classic diffuse connective tissue disease, the clinical diagnosis of SLE has three specificities: First, its clinical manifestations exhibit multisystem heterogeneity, involving nine organ systems including hematologic, musculoskeletal, and neuropsychiatric systems (12); second, it lacks specific biomarkers, although antinuclear antibodies (ANA) have screening value, about 5% of confirmed patients may present ANA-negative (13); third, the disease course has dynamic evolution characteristics, requiring continuous clinical observation for diagnostic optimization (14).