A Point Mutation Creating a 3' Splice Site in Is a Predominant Cause of C8α-γ Deficiency in African Americans.

C8α-γ deficiency was examined in four unrelated African Americans. Two individuals were compound heterozygotes for a previously reported point mutation in exon 9. mRNA from the remaining six alleles contained a 10 nt insertion between nt 992 and 993 corresponding to the junction between exons 6 and 7.

A 9-year-old boy with chronic urticaria and progressive spondyloarthritis.

A 9-year-old African American boy presented with chronic urticaria and progressive spondyloarthritis. Laboratory tests were abnormal for persistently positive antinuclear antibodies and undetectable total hemolytic complement (CH50) despite normal levels of complement C2, C3, and C4. Ultimately, further testing revealed an underlying deficiency in the immune system that may be associated with autoimmune disease and thus have a bearing on the patient's urticaria and spondyloarthritis.

Autoantibody stabilization of the classical pathway C3 convertase leading to C3 deficiency and Neisserial sepsis: C4 nephritic factor revisited.

C3 deficiency is a rare disorder that leads to recurrent pyogenic infections. Here we describe a previously healthy 18 y/o Caucasian male with severe meningococcal disease. Total hemolytic activity was zero secondary to an undetectable C3.

The complement system in pediatric systemic lupus erythematosus, atypical hemolytic uremic syndrome, and complocentric membranoglomerulopathies.

Purpose Of Review: This review summarizes the recent advances in complement biology and the evolving understanding of these contributions to the pathophysiology and treatment of predominantly pediatric disease syndromes.

Recent Findings: Identification of lupus patients with complete deficiencies of one of the plasma complement proteins enabled the field to move beyond the notion of complement as a laboratory curiosity. Clinical investigation of the manifestations observed in deficient patients has further defined the biology of the system in normal individuals.