Discordance between phenotype and genotype study in Factor V Leiden carriers: a real life experience
1Servizio di Medicina di Laboratorio
2Servizio Trasfusionale, Ospedale di Chioggia (VE)
3Dipartimento di Patologia Clinica, Monselice (PD)
Factor V Leiden (FVL) mutation causes activated protein C (APC) resistance by decreasing the susceptibility of FVa to APC-mediated inactivation. In our Laboratory, the usual approach to the identification of FV deficit includes a combination of genetic and functional tests. The aim of this paper was to highlight the importance to investigate both the genotype and the phenotype in the diagnosis of FVL-APC resistance related thrombophilia. Among a group of 292 subjects examined for thrombophilia, we observed three patients with discordant results of genetic test for the detection of G1691A FV gene mutation and functional APCr assay: the first subject has a mild APC resistance with a wild type genotype; the second one, and her sister, shows a severe APC resistance with a heterozygous genotype. To determine the FV deficit, it is important to associate the molecular analysis of G1691A mutation with the APC resistance test.