11/20. Restrictive interatrial communication with protein-losing enteropathy and coagulopathy in hypoplastic left heart syndrome after Norwood palliation. The Norwood procedure is one option for neonates born with hypoplastic left heart syndrome. We describe a case of an infant with hypoplastic left heart syndrome, palliatively repaired with the Norwood procedure. The infant developed restriction of the interatrial communication, despite atrioseptectomy at the first stage of palliation. Consequently, a protein-losing enteropathy with severe coagulopathy developed which resolved after a repeat atrioseptectomy. ( info) |
12/20. axillary vein thrombosis and congenital dysfibrinogenemia in a commercial pilot: a case report. A 34-yr-old male commercial pilot developed a painful swollen right upper arm following an episode of trauma. Venography confirmed the clinical diagnosis of a right axillary deep venous thrombosis. magnetic resonance imaging suggested the presence of a fibrous tissue band overlying the junction of the right subclavian and innominate veins, potentially creating a thoracic outlet syndrome. A thrombophilia screen revealed an abnormal fibrinogen variant consistent with a diagnosis of congenital dysfibrinogenemia. The pilot was treated with anticoagulant therapy for 4 mo. There were diagnostic difficulties in determining the definitive etiology of the axillary vein thrombosis. Congenital dysfibrinogenemia is a rare condition, which is asymptomatic in the majority, but may manifest with hemorrhage or thrombosis in up to 45% of cases. The clinical management of the pilot and the aeromedical implications of the diagnosis are discussed. ( info) |
13/20. Hypofibrinogenemia caused by a nonsense mutation in the fibrinogen Bbeta chain gene. Congenital hypofibrinogenemia, fibrinogen Tottori II, caused by a nonsense mutation in the fibrinogen Bbeta chain gene, was found in a 68-year-old Japanese female. The plasma fibrinogen level was 99.2 mg dL(-1) as determined by the thrombin time method. No overt molecular abnormalities were observed in purified patient fibrinogen by SDS-PAGE analysis. After sequencing all exons and exon-intron boundaries of three fibrinogen genes, we found a heterozygous single point mutation of T-->G at position 3356 of the patient fibrinogen Bbeta chain gene. This nucleotide mutation results in a nonsense mutation (TAT sequence for Bbeta 41Tyr to TAG sequence for a translation termination signal). The mutation was confirmed by polymerase chain reaction-restriction fragment length polymorphism analysis, since this nucleotide mutation results in a new NheI recognition sequence at this position. These data indicated that the nonsense mutation of the fibrinogen Bbeta chain gene caused a truncated fibrinogen Bbeta chain, which may not be assembled in the fibrinogen molecule. ( info) |
14/20. Compound heterozygous mutations in the gamma-glutamyl carboxylase gene cause combined deficiency of all vitamin k-dependent blood coagulation factors. Hereditary combined deficiency of the vitamin k-dependent coagulation factors II, VII, IX, X, protein c, S and protein Z (VKCFD) is a very rare autosomal recessive inherited bleeding disorder. The phenotype may result from functional deficiency of either the gamma-glutamyl carboxylase (GGCX) or the vitamin k epoxide reductase (VKOR) complex. We report on the third case of VKCFD1 with mutations in the gamma-glutamyl carboxylase gene, which is remarkable because of compound heterozygosity. Two mutations were identified: a splice site mutation of exon 3 and a point mutation in exon 11, resulting in the replacement of arginine 485 by proline. Screening of 100 unrelated normal chromosomes by restriction fragment length polymorphism and denaturing high-performance liquid chromatography analysis excluded either mutation as a frequent polymorphism. Substitution of vitamin k could only partially normalize the levels of coagulation factors. It is suggested that the missense mutation affects either the propeptide binding site or the vitamin k binding site of GGCX. ( info) |
15/20. Compound heterozygosity of novel missense mutations in the gamma-glutamyl-carboxylase gene causes hereditary combined vitamin k-dependent coagulation factor deficiency. Hereditary combined vitamin k-dependent (VKD) coagulation factor deficiency is an autosomal recessive bleeding disorder associated with defects in either the gamma-carboxylase, which carboxylates VKD proteins to render them active, or the vitamin k epoxide reductase (VKORC1), which supplies the reduced vitamin k cofactor required for carboxylation. Such deficiencies are rare, and we report the fourth case resulting from mutations in the carboxylase gene, identified in a Tunisian girl who exhibited impaired function in hemostatic VKD factors that was not restored by vitamin k administration. sequence analysis of the proposita did not identify any mutations in the VKORC1 gene but, remarkably, revealed 3 heterozygous mutations in the carboxylase gene that caused the substitutions Asp31Asn, Trp157Arg, and Thr591Lys. None of these mutations have previously been reported. family analysis showed that Asp31Asn and Thr591Lys were coallelic and maternally transmitted while Trp157Arg was transmitted by the father, and a genomic screen of 100 healthy individuals ruled out frequent polymorphisms. Mutational analysis indicated wild-type activity for the Asp31Asn carboxylase. In contrast, the respective Trp157Arg and Thr591Lys activities were 8% and 0% that of wild-type carboxylase, and their compound heterozygosity can therefore account for functional VKD factor deficiency. The implications for carboxylase mechanism are discussed. ( info) |
16/20. The fibrinogen Aalpha R16C mutation results in fibrinolytic resistance. The fibrinogen Aalpha R16C mutation is a common cause of dysfibrinogenaemia and has been previously associated with both bleeding and thrombosis. However, the mechanism underlying the thrombotic phenotype has not yet been elucidated. This report characterises the defect in fibrinolysis seen as a result of the Aalpha R16C mutation. A young patient with dysfibrinogenaemia (fibrinogen Hershey III) was found to be heterozygous for the Aalpha R16C mutation. Functional assays were performed on the purified fibrinogen to characterise clot formation and lysis with plasmin and trypsin. Consistent with previous results, clot formation was diminished. Unexpectedly, fibrinolysis was also delayed. plasminogen activation was normal, ruling out decreased plasmin generation as the mechanism behind the fibrinolytic resistance. Western blot analysis showed no difference in the amount of bound alpha2-antiplasmin or albumin. When clot lysis was assayed with trypsin substituted for plasminogen, a significant delay was also observed, indicating that defective binding to plasminogen could not explain the fibrinolytic resistance. These results suggest that the defective fibrinolysis is due to increased proteolytic resistance, most likely reflecting changes in clot structure. ( info) |
17/20. Valproate-associated coagulopathies are frequent and variable in children. PURPOSE: valproic acid (VPA) is an antiepileptic drug (AED) commonly used for generalized and focal epilepsies. The clinical relevance of coagulopathies, known as side effects of VPA therapy, especially thrombocytopenia, von Willebrand disease, and a decrease of factor xiii, is still unclear. methods: In our institute, we noticed a high incidence of clinically relevant coagulation problems related to VPA in eight patients within 1 year only and a further seven children with significant coagulopathy were identified in the context of planned surgery. RESULTS: We provide an overview of these patients and all six VPA-induced coagulopathies. CONCLUSIONS: At this time, it cannot be recommended to control all hemostatic parameters in every patient. Whenever an increased bleeding tendency is observed, or before surgical procedures, a platelet count, thrombelastography, prothrombin time, activated partial thromboplastin time, TT, fibrinogen, von willebrand factor, and factor xiii should be examined. With 385 VPA-treated patients per year and 15 cases of coagulation disorders in this period, we estimate the incidence of coagulation disorders related to VPA in children to be nearly 4%. ( info) |
18/20. Bleeding in a patient with lupus anticoagulant without associated hemostatic abnormalities. Bleeding is very rare in patients with lupus anticoagulants in the absence of associated hemostatic abnormalities. Few cases have been reported with attention given to work-up for other coagulation defects. We report a case of spontaneous hematoma in a patient with lupus anticoagulant, immunoglobulin (Ig)M anticardiolipin antibodies, and no other associated abnormalities. ( info) |
19/20. A missense mutation in gamma-glutamyl carboxylase gene causes combined deficiency of all vitamin k-dependent blood coagulation factors. To identify potential mutations in the gamma-glutamyl carboxylase gene, the sequence of all exons and intron/exon borders was determined in 4 patients from a consanguineous kindred with combined deficiency of all vitamin k-dependent procoagulants and anticoagulants and results were compared with normal genomic sequence. All 4 patients were homozygous for a point mutation in exon 9 that resulted in the conversion of an arginine codon (CTG) to leucine codon (CGG) at residue 394. Screening of this mutation based on introduction of Alu I site in amplified fragment from normal allele but not from the mutated allele showed that 13 asymptomatic members of the kindred were heterozygous for the mutation. The mutation was not found in 340 unrelated normal chromosomes. The segregation pattern of the mutation which is the first reported in the gamma-glutamyl carboxylase gene fits perfectly with phenotype of the disorder and confirms the suggested autosomal recessive pattern of inheritance of combined deficiency of all vitamin k-dependent procoagulants and anticoagulants in this kindred. The mutated carboxylase protein expressed in drosophila cells was stable but demonstrated threefold reduced activity compared with WT carboxylase, confirming that the L394R mutation results in a defective carboxylase. ( info) |
20/20. fibrinogen Caracas I: a dysfibrinogenemia with a hemorrhagic diathesis associated with diminished fibrin fiber diameter and reduced fibrin gel porosity. fibrinogen Caracas I is a dysfibrinogenemia with a mild bleeding diathesis and a defective wound healing. We have characterized this abnormal fibrinogen using transmission electron microscopy (TEM) in combination with turbidity and permeation studies. Turbidometric and permeability analysis showed that the abnormal fibrin had a significantly decreased mass:length ratio and fiber diameter. In addition, the permeability studies of plasma fibrin clots showed that the gel porosity of the abnormal fibrinogen was reduced. Images of the abnormal fibrin structure obtained using TEM showed that the fibers were thinner, much less branched and less ordered than normal fibers. Diminished fibrin fiber diameter and reduced fibrin gel porosity have been taken as hallmarks of thrombophilic dysfibrinogenemias. The results of the present study show that these features are not necessarily predictive of thrombophilia. Further studies performed on a larger number of dysfibrinogenemias need to be conducted in order to establish the implications of these parameters on the clinical outcome. ( info) |