Familial Properdin Deficiency and Fatal Meningococcemia

INHERITED deficiencies of various complement proteins are being recognized with increasing frequency. Careful evaluation of these deficiency states has augmented our understanding of the biologic function of individual components of the complement system, as well as of the system as a whole. Approximately half the affected persons are healthy. Nevertheless, typical clinical features have been found in the remainder, and should suggest a diagnosis of complement deficiency and identify the particular component or activation pathway that is defective. 1 , 2 Inherited deficiencies of the nonregulatory components of the alternative pathway have been recognized only rarely. This report describes a large family in . . .