Genetic polymorphism of the third component of human complement (C′3)

Chester A. Alper; Richard P. Propp

doi:10.1172/JCI105904

^{Blood Grouping Laboratory and the Department of Medicine, Children's Hospital Medical Center, Boston, Massachusetts 02115}

^{Blood Grouping Laboratory and the Department of Medicine, Peter Bent Brigham Hospital, Boston, Massachusetts 02115}

^{Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115}

^{Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115}

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^{Blood Grouping Laboratory and the Department of Medicine, Children's Hospital Medical Center, Boston, Massachusetts 02115}

^{Blood Grouping Laboratory and the Department of Medicine, Peter Bent Brigham Hospital, Boston, Massachusetts 02115}

^{Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115}

^{Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115}

Find articles by Propp, R. in: PubMed | Google Scholar

Published in Volume 47, Issue 9 on September 1, 1968
J Clin Invest. 1968;47(9):2181–2191. https://doi.org/10.1172/JCI105904.
© 1968 The American Society for Clinical Investigation

Published September 1, 1968 - Version history

Polymorphism of human C′3 has been defined by prolonged agarose electrophoresis of fresh serum. At least four, and probably five, alleles have been identified by the electrophoretic mobilities of gene products. Inheritance of three alleles, F₁ F, and S, is consistent with the autosomal condominant type. The inheritance of S₁ is probably codominant and that of F_0·8 is not known. Of the 15 phenotypes predicted by these alleles, eight have been observed.

The allotypes appear to differ in net surface charge at pH 8.6, but show no obvious differences in complement activity, in molecular size, or in binding of Ca⁺⁺. The concentrations of the two gene products in serum from all known heterozygotes are approximately equal.

The S gene is most common in the three major races of man. The F gene is relatively common in Caucasians, less common in American Negroes, and relatively uncommon in Orientals.

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