Functional deficiency of complement factor D in a monozygous twin.
An adult twin with recurrent bacterial infections was found to have a partial functional deficiency of complement factor D. Full restoration of alternative pathway activity and zymosan- or cobra venom factor-induced consumption of C3 and B was found after reconstitution of patient's serum with purified D. Family studies revealed normal D levels in the mother, a brother and another sister. After gel filtration of patient's sera only little D activity could be detected in the fractions, and trypsin activation of the fractions also did not uncover detectable precursor D activity.
D000328:Adult; D001424:Bacterial Infections / Q000235:genetics / Q000276:immunology*; D002850:Chromatography, Gel; D003166:Complement Activating Enzymes / Q000172:deficiency*; D011416:Complement Factor D / Q000172:deficiency* / Q000235:genetics; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000032:analysis; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D011247:Pregnancy; D012008:Recurrence; D012141:Respiratory Tract Infections / Q000235:genetics / Q000276:immunology*; D014430:Twins, Monozygotic
D003165:Complement System Proteins; D003166:Complement Activating Enzymes; C493488:CFD protein, human; D011416:Complement Factor D