Which clinical history findings are characteristic of complement deficiencies?

Updated: Apr 28, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Michael A Kaliner, MD  more...
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Answer

Infants may have Leiner disease, which manifests as recurrent diarrhea, wasting, and generalized seborrheic dermatitis. The defect in persons with Leiner disease is usually attributed to a defect of the fifth component of complement (C5). However, a child was described by Sonea and associates who had Leiner disease associated with diminished C3, and another was described by Goodyear and Harper with a low level of the fourth component of complement and reduced neutrophil mobility. [11, 12] Thus, the C5 defect may not be the sole cause of Leiner disease, as has been suggested; diminished C3 or C4, or C5 dysfunction or deficiency with hypogammaglobulinemia or other lymphoid deficiency, is also required for its expression.

One family from the Arabian Gulf region with multiple members affected by meningococcemia and abscent serum complement 5 (C5) was found to have a homozygous nonsense mutation in exon 1, with the change of cytosine to thymine at position 55 (55C > T) leading to change of the glutamine amino acid at position 19 to a stop codon (Q19X), and serologically absence of C5 in the serum. [13]

The 3 major sequelae of complement deficiencies, based on the pathophysiology of each defect, are (1) defects that result in inadequate opsonization, (2) defects in cell lysis, and (3) the association of complement deficiencies with immune complex diseases.


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