Inherited risk factors for thrombophilia in children with nephrotic syndrome

A hereditary tendency to venous thrombosis rarely results in a spontaneous thrombotic episode before puberty. The acquired hypercoagulability associated with nephrotic syndrome (NS) could, however, coincide with underlying inherited thrombophilia, thereby resulting in a thrombotic event. In order to determine the contribution of inherited prothrombotic conditions to thrombosis in children with NS, we analysed DNA from a cohort of patients with NS for the common genetic risk factors of vascular disease. We evaluated 53 children with NS and 41 paediatric controls for prevalence of the factor V mutation Arg506-->Gln (factor V Leiden), the prothrombin variant (20210G-->A), and homozygosity for Ala677-->Val in the methylenetetrahydrofolate reductase gene (MTHFR). Eight thrombo-embolic events were identified in 6 out of 53 (11%) children. Three thrombotic events occurred during NS activity and were associated with systemic infections in two and an arterial puncture in one. An inherited risk factor was identified in seven children, all without thrombosis (two heterozygous for the prothrombin variant and five homozygous for the MTHFR-T). None of the studied inherited risk factors were identified among those with thrombosis.

These data suggest that inherited thrombophilia is not a strong risk factor for the development of non recurrent thrombosis in children with NS.