FV Leiden mutation causes activated protein C (APC) resistance and causes an increase in thrombin level. Although moderate bleeding is seen in severe factor V deficiency, less than 1% of patients experience bleeding. Cases in which thrombosis is prominent in the presence  FV Leiden mutation and FV deficiency have been reported. Here, we present a patient with FV deficiency with FV Leiden heterozygous mutation in the etiology of recurrent abortion.

A 41-year-old female patient who applied to her primary care physician with bilateral lumbar pain upon finding INR: 1.43 (0.8-1.2) and APTT: 37.6 seconds (25-36.5), the patient was recommended to apply to our out patient clinic. The patient who described two spontaneous abortions (at the age of 25, the first in the 2nd trimester and the other in the 3rd trimester), also had a history of ecchymosis in the extremities caused by minor trauma at intervals.

PT, INR and APTT returned to normal with the mixing test performed on the patient (12.1 sEC, 1.03 and 28.6 sec, respectively).Afterwards, FV, which is one of the factors in the common pathway of coagulation, was found low in the examination repeated twice (12.3% and 10.2%) (N: 62-139%). The APCR studied twice in screening for thrombophilia was 1.4  and 2.4 (N: 2.61-3.32) Protein C, protein S, antithrombin III levels were within normal limits, LAC and APA were negative.

According to this result, FV Leiden heterozygous mutation was detected in the genetic thrombophilia panel. Also the patient had FV deficiency .

Authors termed the coexistence of heterozygous FV Leiden mutation and type1 FV deficiency as pseudohomozygous FV Leiden mutation. In our and other studies, we concluded that thrombosis was clinically significant, where as bleeding was rare and mild. We think that prolonged PT and APTT results in patients with a history of thrombosis with FV Leidenmutation are also stimulating in evaluating FV activity.