Retinal vascular occlusion and deficiencies in the protein C pathway

PURPOSE: To report abnormalities in the protein C pathway and other vascula r occlusion risk factors in patients with retinal vascular occlusion, METHODS: In a study, we investigated 76 consecutive patients who had in-pat ient evaluation of venous or arterial retinal vascular occlusion. All patie nts underwent comprehensive tests for coagulation disorders including deter minations of protein C, protein S, lupus anticoagulants, and resistance to activated protein C and were screened for vascular disease risk factors. Re sistance to activated protein C was confirmed by a polymerase chain reactio n method to detect the specific factor V R506Q mutation. For comparative pu rposes, we also screened 209 consecutive inpatients with deep vein thrombos is from the same geographic region for resistance to activated protein C as well as protein C and protein S deficiencies. RESULTS: Ten (29%) of 35 patients with central retinal vein occlusion (CRVO ) had factor V R506Q mutation. The factor V R506Q mutation was detected in four (19%) of 21 patients with branch retinal vein occlusion. The higher fr equency in factor V R506Q mutation compared with the expected 9% mutation p revalence in a white population was highly significant for the central reti nal vein occlusion group but not for the branch retinal vein occlusion grou p. In all patients with resistance to activated protein C, the factor V R50 6Q mutation was detected; 16 were heterozygous, one homozygous, No cases of lupus anticoagulants, protein C, or protein S deficiencies were detected. Forty (19%) of 209 patients with deep vein thrombosis were carriers of the factor V R506Q mutation. CONCLUSIONS: The prevalence of the factor V R506Q mutation is similar in pa tients with central retinal vein occlusion and patients with deep vein thro mbosis and represents a relevant risk factor. Screening for this mutation i s therefore recommended in all patients with central retinal vein occlusion . (Am J Ophthalmol 1999;128:69-74; (C) 1999 by Elsevier Science Inc. All ri ghts reserved.)