RESUMO
INTRODUCTION: Retinal vein occlusions (RVOs) are rare in the younger population. Hematological pro-thrombotic factors are thought to be important in a minority, amplifying an atherosclerotic anatomical predisposition. CASE REPORT: Anotherwise healthy 13-year-old girl presented two episodes of sudden decreased vision in few months.Ophthalmological exams pointed out post-thrombotic intra-retinal hemorrhage. All investigations were normal, thrombophilia screen showed factor XII deficiency and genetic mutations of methylenetetrahydrofolate reductase (MTHFR), angiotesin convertin enzyme (ACE) and angiotensinogen (AGT). Two intravitreal injection of bevacizumab was administered with improving visual acuity; subsequently the patient did not report further episodes. DISCUSSION: In addition to traditional factors with procoagulant activity, factor XII deficiency plays an important role in thrombosis's mechanism. Its deficiency causes a marked prolongation of the activated partial thromboplastin time in the laboratory examination. Moreover also MTHFR, ACE and AGT could have been involved in this case, so it is important to evaluate these parameters in the differential diagnosis of RVOs.
