First Korean case of factor V Leiden mutation in pregnant woman with a history of recurrent pregnancy loss

Recurrent pregnancy loss (RPL) has been public health concern, developed 1 in 300 pregnancies and 2-4% of reproductiveaged couples. RPL is defined as 2 or more spontaneous abortions before the 20th week of gestation [1]. An estimated 50% of RPL is idiopathic. Most couples with RPL should be evaluated for genetic and non-genetic causes. Thrombophilia has been suggested as one putative etiology of RPL [2]. Inherited thrombophilia is a genetic disorder of blood coagulation resulting in an unusual hypercoagulable state, which in turn can result in abnormal implantation and may manifest as spontaneous fetal loss [3]. The inherited predisposition to thrombophilia is most often associated with factor V Leiden (FVL) mutation (c.1601G>A), coagulation factor II (F2, also known as prothrombin) gene variant (c.20210G>A), and methylenetetrahydrofolate reductase (MTFHR) gene variants (c.677C>T and c.1298A>C) [4]. Activated protein C (APC) resistance is known to be the most frequent genetic cause of venous thrombosis, accounting for up to 40% of all thromboses. The FVL mutation, inherited as an autosomal dominant trait, is responsible for 95% of cases of APC resistance [5]. The FVL mutation is caused by a point mutation in the F5 (OMIM 612309, NM_000130.4), encoding a substitution of arginine for glutamine at position 534 of the factor V