Autoimmune Manifestations in Heterozygote Type I Complement 2 Deficiency: A Child Eventually Diagnosed With Systemic Lupus Erythematosus
Rabia Miray KIŞLA EKİNCİ1, Sibel BALCI1, Atil BİŞGİN2, Bahriye ATMIŞ3, Dilek DOĞRUEL4, Mustafa YILMAZ1
1Department of Pediatric Rheumatology, Medicine Faculty of Çukurova University, Adana, Turkey
2Department of Medical Genetics, Medicine Faculty of Çukurova University, Adana, Turkey
3Department of Pediatric Nephrology, Medicine Faculty of Çukurova University, Adana, Turkey
4Department of Pediatic Allergy and Immunology, Medicine Faculty of Çukurova University, Adana, Turkey
Keywords: Child, complement 2, cutaneous vasculitis, systemic lupus erythematosus
Systemic lupus erythematosus (SLE) is an autoimmune disorder resulting in a broad spectrum of manifestations in several organs, mainly skin and kidney. SLE occurs with interaction of genetic and environmental factors. The most remarkable genetic predisposition to SLE is deficiency of early components of the classical complement pathway. A five-year-old, previously healthy female patient was admitted to our hospital with headache, fever, focal partial seizure, diagnosed and treated as encephalitis. She was re-admitted to our hospital at six years of age with fever, fatigue, alopecia and oral aphthous ulcers and necrotizing vasculitis on extremities. Significant hypocomplementemia, anemia, proteinuria and positive autoantibodies and coombs test led to the diagnosis of SLE. Due to early disease onset and distinct autoimmune manifestations, we diagnosed our patient with type I complement 2 (C2) deficiency with a frameshift mutation in C2 gene and a serum C2 level of <0.2 mg/dL. To our knowledge, this is the first case of genetically confirmed and successfully treated hereditary C2 deficient SLE patient diagnosed with necrotizing vasculitis. We wish to highlight that distinctive autoimmune manifestations should guide physicians to research on monogenic lupus, particularly C2 deficiency, even in the absence of coexisting recurrent pyogenic infections.