Childhood-onset systemic lupus erythematosus associated with inborn errors of immunity: One or several conditions?

Childhood-onset systemic lupus erythematosus (cSLE) is a multisystem disease; its severity depends on the organs involved. Monogenic diseases have been described as predisposing to the onset of cSLE. Analytical and immunological tests are used for diagnostic confirmation. The main goal of treatment is remission and flare prevention. Here we describe the clinical case of a patient with prolonged febrile syndrome, arthralgias, and anemia, positive analytical tests for antinuclear antibodies and anti-DNA antibodies and low values of complement C3, C4, and C1q; so the patient was diagnosed with cSLE associated with C1q deficiency. Patients with C1q deficiency present with early onset of disease and significant target organ damage with nephritis. An early diagnosis of cSLE is important to ensure an early and appropriate treatment. Treatment may be personalized depending on the underlying defect that generates the subtype of lupus.