Abdominal venous thrombosis in neonates and infants: role of prothromboticrisk factors - a multicentre case-control study

The factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, th e methylenetetrahydrofolate reductase (MTHFR) T677T genotype, together with fasting homocysteine (HCY) concentration, lipoprotein (Lp)(a), anti-thromb in (AT), protein C (PC), protein S (PS) and anti-cardiolipin antibodies wer e investigated in 65 consecutively recruited infants (neonate to < 12 month s) with renal venous thrombosis (RVT; n = 31), portal vein thrombosis (PVT; n = 24) or hepatic vein thrombosis (HVT n = 10), and 100 age- and sex-matc hed healthy controls. FV G1691A was found in 14 babies (heterozygous: RVT n = 9, PVT n = 4; homozygous HVT n = 1) and five controls, the MTHFR TT677 g enotype together with increased HCY in four infants with thrombosis (RVT n = 2; PVT n = 1; HVT n = 1) compared with one control, and the PT G20210A va riant was present in one control only. PC type I deficiency was diagnosed i n three patients (RVT n = 2; PVT n = 1) and AT deficiency in two patients ( RVT n = 1; PVT n = 1). Three neonates with spontaneous thrombosis showed FV G1691A combined with Lp(a) and the FV G1691A was combined with the PT G202 10A genotype in two infants. Additional triggering factors were reported in 27 patients (41.5%). The overall odds ratios (ORs) and 95% confidence inte rvals (CIs) with respect to the different thrombosis locations were: RVT (O R/CI: 10.9/3.85-31.1; P < 0.0001), PVT (5.47/1.7-17.6; P < 0.0007) and HVT (3.3/0.58-18.7; P = 0.18). The data presented here suggest that genetic pro thrombotic risk factors also play an important role in abdominal venous thr ombosis during infancy.