Genetic prothrombotic mutations are common in neonates but are not associated with umbilical catheter-associated thrombosis.
OBJECTIVE
To evaluate the prevalence of hereditary prothrombotic mutations, and their effect on the incidence and severity of umbilical arterial or venous catheter (UAC or UVC)-associated thrombosis.


METHODS
All neonates with a UAC or UVC were studied prospectively for the presence, severity and timing of thrombosis with duplex Doppler ultrasound scan. Genetic testing for factor V Leiden (FVL), prothrombin mutation (PTm) and methylene-tetrahydrofolate reductase (MTHFR) mutations was performed using PCR and restriction fragment length polymorphism assays.


RESULTS
Umbilical catheter (UC)-associated thrombosis developed in 16/53 (31%) neonates; 23% of UACs and 22% of UVCs were associated with thrombosis. The prevalence of a significant prothrombotic mutation was present in 10/51 (20%) of infants: FVL (8%), MTHFR667 homozygosity (10%), MTHFR1298 homozygosity (2%) and PTm (0%). There was no increase in the risk of UC-associated thrombus in patients carrying these prothrombotic mutations; our study had the power to detect a 2.5-fold increased risk of thrombosis for any of these significant mutations. In addition, MTHFR667 heterozygosity was found in 41% of infants and MTHFR1298 heterozygosity in 52% and also were not associated with increased risk of UC-associated thrombus. The risk of MTHFR double heterozygosity (db het) was 14%, the risk of a significant or db het was 17/51 (33%) and the risk of any mutation was 90%.


CONCLUSIONS
Prothrombotic genetic mutations are common in our Neonatal Intensive Care Unit population but do not appear to increase the risk of UC-associated thrombosis.
Turebylu
R
R
Division of Neonatology, Department of Pediatrics, State University of New York at Buffalo, Women and Children's Hospital of Buffalo, Buffalo, NY 14222-2006, USA.
Salis
R
R
Erbe
R
R
Martin
D
D
Lakshminrusimha
S
S
Ryan
R M
RM
D002408:Catheters, Indwelling / Q000009:adverse effects*; D005165:Factor V / Q000235:genetics*; D005260:Female; D006579:Heterozygote; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D011446:Prospective Studies; D011516:Prothrombin / Q000235:genetics*; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000235:genetics; D018616:Ultrasonography, Doppler, Duplex; D014469:Umbilical Arteries; D014471:Umbilical Veins; D020246:Venous Thrombosis / Q000209:etiology*
C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin; D042965:Methylenetetrahydrofolate Reductase (NADPH2)