title: Hereditary Heterozygous C2 Deficiency: Variable Clinical and Serological Manifestations Among Three Sisters.
abstract: The causal link between inherited complement deficiencies and systemic lupus erythematosus (SLE) has been well established, although it remains a rare cause of the disease. We present the case of three biological sisters with hereditary heterozygous C2 deficiency, but who differ widely in their clinical and serological manifestations. Patient 1 is 25 years old and was diagnosed with SLE at the age of 12. Further testing revealed positive ANA and anti-dsDNA, antiphospholipid syndrome (APS) and decreased C2, C3 and C4 levels. Patients 2 and 3 are 21-year-old dizygotic twins. Both have positive ANA and antiphospholipid (APL) antibodies, and decreased C2 and C4 levels. We present a case of familial heterozygous C2 deficiency with different disease phenotypes. The presence of positive APL antibodies in all 3 patients is significant, as this association has been rarely described. The variable clinical and serological manifestations among our patients further reflect the complex and multifactorial nature of SLE.
authors: Rheumatology Division, Department of Medicine, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada.
authors: Ji Wei
authors: JW
authors: Yang
authors: Rheumatology Division, Department of Medicine, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada.
authors: Eric
authors: E
authors: Rich
authors: Rheumatology Division, Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Quebec, Canada.
authors: Claire
authors: C
authors: Saint-Cyr
authors: Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, 1560 Sherbrooke Street East, Montréal, QC H2L 4M1, Canada.
authors: Josiane
authors: J
authors: Bourré-Tessier
mesh_terms: D000328:Adult; D003175:Complement C2 / Q000172:deficiency*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000235:genetics* / Q000276:immunology*; D010641:Phenotype; D035781:Siblings; D055815:Young Adult
chemical_list: D003175:Complement C2
keywords: Systemic lupus erythematosus; antiphospholipid syndrome; autoimmune disorders; complement deficiency