Protein C in the Neonatal Period

Takahashi, Osamu; Kinoshita, S.; Niinomi, K.; Yoshioka, Kōta

doi:10.1159/000215887

Cited by 3 publications

(1 citation statement)

References 4 publications

(4 reference statements)

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“…As protein C is a vitamin K‐dependent anticoagulant enzyme synthesized by hepatocytes, it is considered that the protein C activity is physiologically low in the neonatal period (Tardy‐Poncet et al , 2001). Though the protein C activity in our patient was low during infancy (25% at 4 months and 49% at 1 year of age), the normal level of protein C activity at the same age was reported to be 57% and 88% respectively (Takamiya et al , 1989). Taking into account these values and his mother's protein C deficiency (64%), a protein C activity of 25% would be comparable to a heterozygous protein C deficiency.…”

Section: Discussionmentioning

confidence: 48%

Identification of simultaneous mutation of fibrinogen α chain and protein C genes in a Japanese kindred

et al. 2002

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Summary. Afibrinogenaemia usually induces a bleeding tendency during infancy, whereas protein C deficiency increases susceptibility to thrombosis in children or adolescence. Mutations of these genes have been, therefore, established as independent risk factors for coagulation disorders. We describe the homozygous mutation of the fibrinogen a chain gene and additional heterozygous mutation of the protein C gene in a male infant who showed prolonged umbilical bleeding after birth. On examination, the plasma fibrinogen was undetectable, and the activity and antigen level of protein C were reduced. The patient showed no fibrinogen Aa chain as well as Bb and c chains by Western blotting. The sequencing analysis showed the homozygous deletion of 1238 bases from intron 3 at position 2008 to intron 4 at position 3245 in the fibrinogen a chain gene. Both parents were heterozygous carriers of this mutation. In this patient, an additional mutation was also detected in the protein C gene: the heterozygous deletion of exon 7 at position 6161-6163 or 6164-6166, resulting the deletion of one amino acid (Lys150 or 151). His mother was also a carrier of this mutation. As the simultaneous mutation of the fibrinogen a chain and protein C genes has not been previously reported, the influence of the interaction between these two mutations on the clinical manifestations of this patient should be carefully monitored for a long period.

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Section: Discussionmentioning

confidence: 48%

Identification of simultaneous mutation of fibrinogen α chain and protein C genes in a Japanese kindred

et al. 2002

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Vitamin K1 metabolism and the production of des-carboxy prothrombin and protein C in the term and premature neonate

Bovill

Soll

Lynch

et al. 1993

Blood

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This study investigated the incidences of undercarboxylated (protein induced by vitamin K absence: PIVKA) prothrombin and protein C in 496 neonates across a wide range of gestational ages. These findings are related to vitamin K1 levels (an indicator of cofactor availability) and vitamin K1 epoxide levels (a measure of the efficiency of the hepatic vitamin K cycle). PIVKA protein C was present in at least trace amounts in 27% of infants; whereas, PIVKA prothrombin was present in 7% of infants. PIVKA prothrombin and protein C were present at high plasma concentrations in 2% to 3% of term and preterm neonates and both PIVKA protein C and prothrombin increased with gestational age. Despite elevated plasma concentrations of PIVKA protein C and diminished levels of normally carboxylated protein C, clinical thrombosis was not observed. The mean (+/- SD) vitamin K1 level in the study population was 0.009 +/- 0.02 nmol/L (adult reference interval: 0.3 to 2.6 nmol/L) with no clear relationship between vitamin K1 levels and production of PIVKA protein C or prothrombin. By comparison with adults, the epoxide form of the vitamin comprised an abnormally high proportion of total vitamin K1; this suggests possible inefficiencies in hepatic reductase cycling.

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Evolution of blood coagulation activators and inhibitors in the healthy human fetus

Reverdiau-Moalic¹,

Delahousse²,

Body³

et al. 1996

Blood

212

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Blood coagulation proteins were determined in 285 healthy fetuses from 19 to 38 weeks' gestation and compared with those of 60 normal full- term newborns and 40 adult controls. Prolongation of the coagulation screening tests, prothrombin time, activated partial prothrombin time, and thrombin clotting time, in fetuses throughout intrauterine life was explained by low levels of vitamin K-dependent factors (II, VII, IX, and X), contact factors (XI, XII, prekallikrein, and high-molecular- weight kininogen), factor V, factor VIII, and fibrinogen. Low levels of antithrombin III, heparin cofactor II, protein C and protein S, and tissue factor pathway inhibitor were also found, and these probably contributed to a satisfactory hemostatic balance. Some of these parameters were evaluated by both immunologic and functional assays to detect possible “fetal” proteins. An increase in factor levels was observed after the thirty-fourth week of intrauterine life for most of the coagulation activators and inhibitors, but only factors V and VIII reached adult values at birth. This study therefore showed that fetal hemostasis is a dynamic system that evolves gradually toward the neonatal state and then toward the adult state.

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Protein C in the Neonatal Period

Cited by 3 publications

References 4 publications

Identification of simultaneous mutation of fibrinogen α chain and protein C genes in a Japanese kindred

Identification of simultaneous mutation of fibrinogen α chain and protein C genes in a Japanese kindred

Vitamin K1 metabolism and the production of des-carboxy prothrombin and protein C in the term and premature neonate

Evolution of blood coagulation activators and inhibitors in the healthy human fetus

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