title: Ophthalmic manifestation of congenital protein C deficiency.
abstract: Under normal conditions activated protein C is a natural anticoagulant that cleaves 2 activated coagulation factors, factor Va and factor VIIIa, thereby inhibiting the conversion of factor X to factor Xa and of prothrombin to thrombin. Additionally, activated protein C enhances tissue-plasminogen activator-mediated fibrinolysis by inhibition of plasminogen activator inhibitor-1. This results in an increase in circulatory plasminogen activator levels. Protein C deficiency, a genetic or acquired thrombophilic abnormality, has been demonstrated to predispose to episodes of potentially blinding and lethal thromboembolic events. Heterozygous-deficient subjects usually remain asymptomatic until adolescence or adulthood. In homozygous-deficient patients, protein C activity is usually less than 1% (reference range, 70%-140%), resulting in thromboembolism as early as in the neonatal period. The major clinical symptoms in affected newborn infants have been purpura fulminans, vitreous hemorrhage, and central nervous system thrombosis. The age of onset of the first symptoms has ranged from a few hours to 2 weeks after birth, usually after an uncomplicated full-term pregnancy and delivery. In contrast to the genetic form, acquired neonatal protein C deficiency occurs particularly in ill preterm babies. Typical complications of prematurity such as respiratory distress syndrome, necrotizing enterocolitis, and neonatal sepsis may also be present. In the medical literature, there are only a few reports of homozygous protein C deficiency in neonates. We present 2 cases of homozygous protein C deficiency with ocular and extraocular manifestation.
authors.affiliation: Department of Ophthalmology, Johann Wolfgang Goethe University Hospital, Frankfurt am Main, Germany. Hattenbach@em.uni-frankfurt.de
authors.forename: L O
authors.initials: LO
authors.lastname: Hattenbach
authors.forename: T
authors.initials: T
authors.lastname: Beeg
authors.forename: W
authors.initials: W
authors.lastname: Kreuz
authors.forename: A
authors.initials: A
authors.lastname: Zubcov
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use; D002386:Cataract / Q000151:congenital; D003241:Consanguinity; D003374:Coumarins / Q000627:therapeutic use; D005128:Eye Diseases / Q000097:blood / Q000151:congenital* / Q000188:drug therapy; D005260:Female; D006801:Humans; D011695:IgA Vasculitis / Q000151:congenital; D007231:Infant, Newborn; D008850:Microphthalmos / Q000209:etiology; D011486:Protein C / Q000378:metabolism / Q000627:therapeutic use; D020151:Protein C Deficiency / Q000097:blood / Q000151:congenital* / Q000188:drug therapy; D012163:Retinal Detachment / Q000151:congenital; D012166:Retinal Hemorrhage / Q000151:congenital; D014823:Vitreous Hemorrhage / Q000151:congenital
chemical_list: D000925:Anticoagulants; D003374:Coumarins; D011486:Protein C; C030123:coumarin