Background: Factor V Leiden (FVL) mutation and protein C (PC) deficiency are inherited thrombophilias that lead to an increased risk of thrombosis and their individual effect on thrombotic risk has been described before. However, very few cases of concurrence have been described.
Aims: We describe the follow-up of a now 10-year-old Caucasian female diagnosed with protein C deficiency and homozygous factor V mutation with a severe presentation at birth.
Methods: Collected data was obtained from patient record.
Results: In 2011, our newborn patient underwent right hand catheterization at birth, following a tonic-clonic seizure. Soon after, she developed persistent upper limb cyanosis, which prompted the diagnosis of either severe arterial spasm or arterial thrombosis. Cyanosis later improved, but not completely, which ultimately led to necrosis and amputation of the 2nd to 4th fingertips.
Brain magnetic resonance imaging also showed multiple hypoxic-ischemic lesions, while cerebral ultrasound was suggestive of bilateral infarction.
There was no family history of thrombophilic defects. Thrombophilia testing revealed type I PC deficiency (PC:activity 21%; PC:antigen 26%) and homozygous FVL mutation. PROC gene sequence analysis detected a heterozygous mutation.
Due to the severity of this episode and the presence of two major inherited thrombotic risk factors, indefinite anticoagulation was proposed. Low-molecular-weight-heparin (LMWH) was given initially, with anti-Xa monitoring. At 21 months old, LMWH was switched to oral anticoagulation with vitamin K antagonist.
Neurodevelopment of our now 10-year-old patient has been normal, with no recorded sequelae of hypoxic-ischemic encephalopathy. No new thrombotic events were registered or suspected, while also not presenting any major bleeds, partially due to the fact of having a time in therapeutic range (TTR) above 90%.
Conclusion(s): Co-inherited thrombophilias may present a challenge at presentation, especially in the absence of family history. The coexistence of multiple thrombophilic disorders and its possible supra-additive effect on overall thrombotic risk is not well clarified.
To cite this abstract in AMA style:Sarmento A, Almeida C, Mendes M, Borges L. Co-inheritance of protein C deficiency and homozygous factor V Leiden mutation: 10-year follow-up on a case with severe presentation. [abstract]. https://abstracts.isth.org/abstract/co-inheritance-of-protein-c-deficiency-and-homozygous-factor-v-leiden-mutation-10-year-follow-up-on-a-case-with-severe-presentation/. Accessed October 1, 2023.
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