Familial elevated factor VIII in children with symptomatic venous thrombosis and post-thrombotic syndrome: results of a multicenter study.

OBJECTIVE: To evaluate the role of factor (F) VIII in children with non-cancer related venous thrombosis (DVT), post-thrombotic syndrome (PTS) or recurrent DVT. METHODS AND RESULTS: FVIII levels were measured in White patients and age- and gender-matched healthy controls. Heritability of factor VIII was estimated in 99 pedigrees by the variance component method implemented in SOLAR. The group of 103 patients showed higher median values of FVIII than 206 controls [FVIII:Ag, 115 versus 96 IU/dL, P<0.0001; FVIII:C, 119 versus 106 IU/dL, P=0.0009], and had a significantly increased odds ratio (OR) for fibrinogen-adjusted elevated FVIII levels [FVIII >90th percentile versus values below the cut-off: FVIII:Ag, OR 4.3, 95% confidence interval (CI) 1.5 to 12.1; FVIII:C, OR 5.5, CI 2.03 to 15.06]. PTS occurred in 19 of 59 children and persisted in 5 individuals. Recurrent DVT was seen in 8 patients. The heritable(h2)/household(c2) components were calculated for FVIII:Ag levels (h2, 0.48+/-0.15, P=0.0008; c2, 0.21), and FVIII:C (h2, 0.61+/-0.15, P<0.0001; c2, 0.41). When incorporating h2 and c2 in the estimate, the phenotypic variance for FVIII:Ag levels is predominantly explained by h2, whereas c2 stayed significant in the model for FVIII:C (P=0.00002). CONCLUSIONS: Elevated FVIII levels increase the DVT-risk in children.

Resistance to activated protein C due to factor V Leiden mutation: high prevalence in patients with post-thrombotic leg ulcers.

BACKGROUND: Activated protein C (APC) resistance is the most frequently diagnosed heritable thrombophilic defect predisposing to thrombosis. OBJECTIVES: To determine the prevalence of APC resistance due to factor V Leiden mutation in patients with leg ulcers. METHODS: Within a 2-year-period 100 consecutive patients with leg ulcers were examined for factor V Leiden mutation. RESULTS: APC resistance due to factor V Leiden mutation was detected in 19 of 53 patients (36%) with post-thrombotic leg ulcers and in three of 47 patients (6%) with ulcers caused by primary varicosis. In a healthy control group APC resistance due to factor V Leiden mutation was found in five of 96 (5%) volunteers. CONCLUSIONS: In view of this high prevalence of APC resistance of 36%, which has never previously been reported, patients with post-thrombotic leg ulcers should be investigated for APC resistance.

Combined genetic defect (homogeneity for factor V Leiden and heterogeneity for prothrombin G20210A allele), in a young patient, with recurrent deep vein thrombosis and serious postphlebitic syndrome--a case report.

Just a few years ago, resistance to activated protein C (APCR) was reported to be of high significance representing a strong predisposing factor in the development of venous thrombosis (VT). A little while later, APCR was established to be the result of a point mutation of the factor V gene (factor V Leiden: a G-to-A transition at position 1691). Up to today, it is not certain whether factor V Leiden is in itself able to lead to VT, or whether it acts in synergy with other factors. Nevertheless, heterozygous subjects have a tenfold increase in the risk of VT when compared to general population, whereas the risk is 80 times greater in homozygous individuals. In 1996, a prothrombin gene mutation (prothrombin G20210A allele), which is a single-nucleotide G-to-A transition at position 20210 in the sequence of the 3'-untranslated region (3'UTR) on chromosome 11, was discovered. The presence of this mutant gene results in elevated plasma prothrombin concentrations, increasing the possibility for the development of VT. However, the coexistence of these two abnormalities, as well as the clinical consequence, have not yet been studied. So far, only a few reports are found in the literature describing the coexistence of both mutations. The authors present a 25-year-old patient with a simultaneous double mutation of the FV and F II gene. The patient was homozygous for the factor V Leiden and heterozygous for the prothrombin G20210A allele. It is unclear whether the coexistence of the two predisposes more to the development of VT than the summation of the two as independent factors.

[Recurrent thrombophlebitis and ulcera crurum as manifestations of hereditary blood coagulation disorders and Klinefelter syndrome. Discussion based on 4 case examples]. / Rezidivierende Phlebothrombosen und Ulcera crurum als Manifestationsformen hereditärer Gerinnungsstörungen und des Klinefelter-Syndroms. Diskussion anhand von 4 Fallbeispielen.

Recurrent phlebothromboses in young patients with subsequent severe postthrombotic syndrome and chronic venous leg ulcers may be caused by underlying hereditary disorders of hemostasis or may occur as part of other congenital syndromes. The most common hereditary disorders of hemostasis in this respect appear to be deficiencies of antithrombin III, protein C, and protein S, and activated protein C resistance (mutations of factor V). Less frequently, dysfibrinogenemia, increased plasminogen activator inhibitor levels, or deficiencies of tissue plasminogen activator or heparin cofactor II may be found. Klinefelter's syndrome and homocystinuria are prime examples of those rare congenital disorders indirectly associated with an elevated risk of thrombosis in young individuals. Early diagnosis of these disorders will allow timely treatment, preventive care and counselling of patients as well as family members.

Occult antithrombin III deficiency: a potentially lethal complication of the postphlebitic limb.

Chronic venous insufficiency is a frequent sequel to lower extremity venous thrombosis. A relatively uncommon, but potentially lethal, cause of the thrombosis is congenital antithrombin III deficiency. Recognition and treatment of this occult deficiency is critical. The following report describes a family treated by the authors for this problem. In one generation of nine siblings, three males had documentation of the disease with functional antithrombin III levels in the range of 50% to 60%. Before evaluation for the deficiency one female sibling died at the age of 20 years as a consequence of a proven pulmonary embolus. Antithrombin III levels in another female sibling, who was free of symptoms, were normal (80% to 120%). Four other siblings who were free of symptoms (one female, three males) refused evaluation. All three men with the deficiency had severe, chronic, bilateral, lower extremity, venous insufficiency manifested by pain, varicosities, edema, pigmentation, and ulceration. Despite chronic warfarin therapy, one experienced recurrent pulmonary embolization with eventual loss of perfusion of the entire right lung. Ascending venography in the symptomatic males with the deficiency revealed evidence of recurrent and diffuse venous thrombosis with partial recanalization. Recurrent lower extremity venous thrombosis consequent to antithrombin III deficiency causes a particularly fulminant postphlebitic syndrome with characteristic venographic findings. Although potentially lethal if unrecognized and treated simply as venous insufficiency, chronic therapy with warfarin offers palliation and prolongs life.