Treatment of children with haemophilia in Europe: a survey of 20 centres in 16 countries.

A survey was made of the current status of treatment of haemophilic boys at 20 centres in 16 European countries and includes approximately 1500 of the estimated 6500 haemophiliacs in the participating countries. Many mild haemophiliacs are not seen, or seen infrequently, at haemophilia centres and this requires study. Nine of 18 centres provide continuous prophylaxis to 80-100% of their patients, five centres provide it to 55-80% and the remaining four centres to 15-40% of the boys. The median dose given was 6240 U kg-1 year-1 (range 3120-7800). Four centres administered only recombinant concentrates to children with severe haemophilia A, while seven centres administered recombinant concentrates to 75-90% and the remaining centres to less than 50% of the boys (two centres < 10%). When asked for the choice of concentrate for a newly diagnosed boy with severe haemophilia A, all but one centre preferred recombinant concentrate. Most boys below 6 years received concentrates via a peripheral vein but three centres preferred a central venous line for 80-100% of the boys. Thirteen of 18 centres applied home treatment to 84-100% of the boys and the remaining five centres to 57-77% of the boys.

Molecular biology and clinical manifestation of hereditary factor VII deficiency.

Inherited factor VII (FVII) deficiency is a rare autosomal recessive disorder. Mutations and polymorphisms of the FVII gene were characterized in more than 40 unrelated patients with FVII deficiency. Among the 29 different mutations, the most frequent were Ala294 Val, Ala294Val;404delC, IVS7+7, and Val281 Phe. Four novel mutations (IVS2+1G>C, Arg247 Cys, Glu265 Lys, Asp343 His) were detected. The relationships between genotypes of mutations and polymorphisms of the FVII gene, FVII deficiency, and clinical phenotype were investigated. Homozygosity of the Phe4 Leu, IVS4+1G>A, Cys135 Arg, Ala244 Val, and Ala294 Val;404delC and the double heterozygosity of Tyr68 Cys / IVS3-1G>A, Val252 Met / IVS2+5G>T, Val281 Phe / Cys135 Arg, Ala294 Val / Val281 Phe, Ala294 Val;404delC / Val281Phe, Ala294 Val;404delC / Arg152 stop, Ala294Val;404delC / Gln(-35) stop, Ala294 Val / Val252 Met, Ala294 Val / Gly156 Asp, and Thr359 Met / Asp242 His were related to clinical symptoms. Double heterozygotes for Arg247 Cys / IVS2+1G>C, Ala206 Thr / Pro303 Arg, Leu(-20) Pro / Val252 Met as well as IVS7+7 /Ala294 Val, IVS7+7 /Ala206 Thr, and IVS7+7 / Met298 Ile were asymptomatic. The clinical symptomatology is rather poor in correlation with the FVII activity. Concerning the clinical phanotype, a correlation seems to exist between specific mutations and clinical symptoms.

Thrombosis of the deep cerebral veins with excessive bilateral infarction in a premature infant with the thrombogenic 4G/4G genotype of the plasminogen activator inhibitor-1.

UNLABELLED: We report on a preterm infant with deep cerebral venous thrombosis, a rare condition in this age group. This premature infant had a gestational age of 33 weeks and normal development until day 18, when he presented with tonic seizures and a tense fontanelle. Ultrasound and computed tomography revealed bilateral haemorrhagic infarction of the whole region drained by the deep cerebral veins, including the periventricular white matter, thalamus and choroid plexus. The child was homozygous for the 4G allele of the plasminogen activator inhibitor-1 (PAI-1) 4G/5G promoter polymorphism. CONCLUSION: In patients with bilateral cerebral infarction, thrombosis of the deep cerebral veins should be considered. In addition the role of prothrombotic risk factors, including PAI-1 4G/5G promoter polymorphism, in cerebral vein thrombosis should be clarified in a multicentre study.

Prothrombin G20210A gene mutation and further prothrombotic risk factors in childhood thrombophilia.

Risk factors for venous thrombosis in adults are the prothrombin G20210A and the factor V (FV) G1691A mutations and hereditary deficiencies of protein C, protein S and antithrombin. However, data are limited on the relevance of these risk factors for thrombosis in children and adolescents. We therefore investigated 261 patients aged 0 to 18 (median 5.7 years, 48% male) with venous thrombosis and controls (n=370) for the presence of prothrombotic risk factors including the prothrombin G20210A mutation. The following frequencies of hereditary risk factors (patients versus controls), odds ratios (OR) and 95% confidence intervals (CI), or results of Fisher's exact test, respectively, were found: prothrombin G20210A, 4.2% versus 1.1%, OR/CI 4.1/1.3 to 12.8; FV G1691A, 31.8% versus 4. 1%, OR/CI 11.0/6.2 to 19.7; protein C deficiency, 9.2% versus 0.8%, OR/CI 12.4/3.7 to 41.6, protein S deficiency, 5.7% versus 0.8%, OR/CI 7.5/2.1 to 26.0; antithrombin deficiency in 3.4% in the patients, but not in the controls, P=0.0003. The prothrombin mutation was combined with the heterozygous FV G1691A mutation (2. 3%) or protein C deficiency (0.3%) in the patients, but not in the controls (prothrombin and FV mutation, P=0.0048; prothrombin and protein C deficiency, not significant). The carrier frequencies and ORs of all hereditary risk factors showed a non-significant trend toward higher prevalences in patients suffering spontaneous thrombosis, compared with those with an additional underlying disease. In conclusion, the prothrombin G20210A and the FV G1691A mutation, deficiencies of protein C, protein S, and antithrombin are important risk factors for venous thrombosis during childhood and adolescence.

Thrombolysis in newborns and infants.

This review analyses literature reports from 1970 to 1998 assessing the use of streptokinase (SK), urokinase (UK) or recombinant tissue-type plasminogen activator (rt-PA) for thrombolytic therapy in neonates and infants. From 1970 to 1998 182 infants were reported to have received SK (n = 54; 29.5%), UK (n = 41; 22.5%) or rt-PA (n = 87; 48%). During thrombolytic therapy no concomitant heparin administration or low dose heparin therapy (5 U/kg/h) were recorded. To perform reocclusion prophylactics heparin was reinitiated at the end of thrombolytic therapy usually in the recommended dosage of 20 U/ kg/h. The overall thrombolytic patency rate in neonates varied from 39% to 86%. Besides bleeding from local puncture sites or recent catheterisation sites (10.4%), pulmonary embolism was reported in 1.1% of the 182 infants. Major bleeding complications, i.e. pulmonary bleeding (0.6%), gastrointestinal bleeding (0.6%) or intraventricular haemorrhage (IVH 2.7%) are rarely reported side effects and only 2 thrombolysis related deaths due to haemorrhage were mentioned. Bleedings reported in the central nervous system (n = 4) mainly occurred in preterm infants (n = 3). In conclusion, data of this preliminary analysis suggest that there is no big difference (p = 0.09; chi2-test) in the efficacy rate between the 3 thrombolytic agents used in the first year of life. In each case an assessment must be made with respect to the relative benefit conferred by thrombolytic therapy in preventing organ or limb damage versus the potential side effects, costs and inconvenience for the childhood patient. Controlled prospective multicentre studies on thrombolytic therapy in neonates and infants are recommended to evaluate patency rates and adverse effects for the different thrombolytic agents used.

Factor V G1691A and prothrombin G20210A in childhood spontaneous venous thrombosis--evidence of an age-dependent thrombotic onset in carriers of factor V G1691A and prothrombin G20210A mutation.

UNLABELLED: Risk factors for venous thrombosis in adults are the prothrombin (PT) G20210A, the factor (F) V G1691A mutations and hereditary deficiencies of protein C, protein S and antithrombin. However, data are limited on the relevance of these risk factors for thrombosis in children and adolescents. We therefore investigated 119 patients aged 0-18 with spontaneous venous thrombosis and controls (n = 100) for the presence of the factor V G1691A mutation and the prothrombin G20210A variant with respect to thrombotic onset and thrombosis location. The following frequencies (patients vs. controls), odds ratios (OR), 95%-confidence intervals (CI) and p-values were found: FV G1691A, 19.3% vs. 5%, OR/CI 4.55/1.66-12.5, p = 0.0038 and prothrombin G20210A, 8.4% vs. 3%, OR/CI 2.96/0.8-11, p = 0.17. A combination of the FV G1691A mutation with the PT G20210A variant was found in 3 children (2.5% of cases) but only once in the controls. With a median (range) age of 2 years (0-17), carriers of the FV mutation were significantly younger compared with patients carrying the PT variant (16 years: 0-18, p < 0.001). Vascular accidents in carriers of the FV mutation occurred in deep veins of the leg (n = 11), cerebral veins (n = 4), renal veins (n = 3) and portal veins (n = 2). Patients with the PT mutation showed spontaneous thrombosis in the majority of cases in the deep veins of the leg (n = 5) and in the central nervous system (n = 2). Combined defects were found in a neonate with renal venous thrombosis and in two adolescents with deep vein thrombosis. CONCLUSION: Data presented here suggest that the heterozygous FV mutation is the most commonly found prothrombotic risk factor responsible for spontaneous thrombosis during infancy and early childhood. In contrast, the PT G20210A variant is likely to be more important during puberty and adolescence.

Role of genetic prothrombotic risk factors in childhood caval vein thrombosis.

UNLABELLED: Childhood caval vein thrombosis has a high incidence especially in the first year of life. Besides deficiencies of protein C, protein S, antithrombin and plasminogen, the factor (F) V G1691A mutation, the prothrombin (PT) G20210A variant, the methylenetetrahydro-folate reductase (MTHFR) TT677 genotype, or increased lipoprotein (Lp) (a) > 30 mg/dl have emerged as important prothrombotic risk factors in childhood vascular accidents. 27 consecutive childhood patients with inferior caval vein thrombosis and 100 healthy age-matched controls were investigated for the presence of these prothrombotic risk factors with respect to the first thrombotic onset. In 19 out of 27, patients thrombosis occurred during infancy; the remaining vascular accidents were diagnosed during puberty. In 13 out of the 19 infants, vascular occlusion occurred spontaneously, five times associated with renal venous thrombosis. 68.4% of patients in the first year of life (n = 13) showed at least one prothrombotic risk factor. The FV mutation (heterozygous n = 4, homozygous n = 1). Lp (a) > 30 mg/dl and kringle 4 repeats < 28 (n = 4), MTH FR TT677 with mild hyperhomocysteinaemia (> 95th age-dependent percentile, i.e. 8.5 micromol/l: n = 3) and antithrombin deficiency type II (n = 1) were diagnosed with an overall odds ratio/95% confidence interval of 9.2/3.1-27.4. In the adolescent group, genetic risk factors were found in 50% of patients investigated (FV mutation (n = 1), PT variant (n = 3); odds ratio/95% confidence interval: 4.2/0.97-18.6). CONCLUSION: Data presented here suggest that genetic prothrombotic risk factors play an important role in childhood caval vein thrombosis. Remarkably, during puberty and adolescence the predominant defect diagnosed was the PT G20210A variant, whereas the FV G1691A mutation had a higher incidence during infancy.

The 677T genotype of the common MTHFR thermolabile variant and fasting homocysteine in childhood venous thrombosis.

Controlled data on the association of MTHFR genotypes, hyperhomocysteinaemia and their interaction with factor V G1691A with childhood thrombosis are not yet available. Therefore we conducted a case-control study comparing 141 childhood patients with venous thrombosis with 345 healthy controls. The MTHFR C677T genotypes, FV G1691A and prothrombin G20210A were evaluated; in addition, fasting homocysteine concentrations were measured in a subgroup of 60 children and 80 healthy controls. 10.4% of the healthy control population showed the MTHFR TT genotype, 34.2% the CT genotype and 55.4% the CC variant. MTHFR genotypes account for fasting homocysteine concentrations in healthy controls (CC: 5.5 micromol/l (4-7.2); CT: 7 micromol/l (3.9-9.8); TT: 12.1 micromol/l (7.7-13.3)) with an upper age-specific 95th percentile of 8.3 micromol/l. The following frequencies (patients versus controls), odds ratios (OR) and 95% confidence intervals (CI) were found for single defects: MTHFR 677TT genotype (10.6% vs. 10.4%; OR/CI: 1.02/0.54-1.93; P = 0.99) and CT genotype (43.8% vs. 34.2%; OR/CI: 2.12/1.42-3.16; P = 0.0000). A combination of FV G1691A mutation and MTHFR 677CT genotype was found in 9.9% of patients and in 2.9% of the controls (OR/CI: 3.8/1.64-8.75; P = 0.027). Fasting homocysteine median (range) concentrations in the patient group were significantly higher than in the controls (7 micromol/l (3-23) vs. 5.5 micromol/l (3-8.4): P = 0.0004), and homocysteine concentrations >8.3 micromol/l were found in 40% of patients vs. 2.5% of the controls (OR/CI: 22/2.64-183; P = 0.0003). Conclusion Data of this childhood case-control study suggest that mildly elevated fasting homocysteine concentrations >8.3 micromol/l and the CT genotype of the MTHFR C677T variant are significant risk factors for venous vascular occlusion in children.

The low molecular weight heparin dalteparin for prophylaxis and therapy of thrombosis in childhood: a report on 48 cases.

UNLABELLED: We investigated the efficacy, safety and relation of dose to plasma anti-Xa activity of the low molecular weight heparin (LMWH) dalteparin in prophylaxis and therapy of arterial and venous thrombosis in pediatric patients. A total of 48 children were enrolled: 10 received dalteparin for prophylaxis (group I), 8 for reocclusion prophylaxis following successful thrombolysis (group II), 5 following failed thrombolysis (group III) and 23 for primary antithrombotic therapy (group IV). Two children were treated with dalteparin for pulmonary veno-occlusive disease (PVOD) and for primary pulmonary hypertension (PPH), respectively. OUTCOME: In group I no thrombo-embolic event occurred. In group II recanalization was maintained or improved, in group III vascular occlusion persisted under dalteparin. In group IV we saw complete recanalization in 7/23 (30%), partial recanalization in 7/23 (30%) and no recanalization in 9/23 (40%) cases. The child with PVOD had recanalization proven by lung biopsy; the clinical condition of the child with PPH also improved. Minor bleeding occurred in 2/48 (4%) children. For prophylaxis 95 +/- 52 (mean and SD) anti-Xa IU/kg BW, for therapy 129 +/- 43 (mean and SD) anti-Xa IU/kg BW proved effective. For both prophylaxis and therapy the required dose per kg BW was inversely related with age (r2 = 0.64, P = 0.017; r2 = 0.13, P = 0.013). CONCLUSION: Dalteparin proved to be an effective and well tolerated drug for prophylaxis and therapy of thrombosis in pediatric patients. Dose requirement for effective treatment was higher in younger children and decreased with age.

Prevalence and outcome of intracranial haemorrhage in haemophiliacs--a survey of the paediatric group of the German Society of Thrombosis and Haemostasis (GTH).

UNLABELLED: A survey among centres of the paediatric group of the GTH was performed to evaluate the prevalence and outcome of haemophiliacs with intracerebral haemorrhage. A questionnaire sent to the centres covered the following points: number of patients with severe, moderate and mild haemophilia A and B; for each patient with ICH: birth date, age at bleeding, aetiology and neurological sequelae. Overall, 30 ICH in 744 haemophiliacs (4.0%) were reported by 17/40 centres (42.5%). There was no significant difference between the prevalence of patients with haemophilia A and B (3.5% vs. 6.3%) and among the age groups. Bleeding was diagnosed within 1 week of birth in 11/27 patients (41%). For 3 patients, no age-related information was given. The most important factor was trauma (17/30 = 57%), either during birth (9/30 = 30%) or later in life (8/30 = 27%). Seizures were common, occurring in 19/30 patients (63%). As 1 patient died after posttraumatic ICH, the neurological outcome of 29 patients could be evaluated. Psychomotor and statomotor retardation and cerebral palsy were reported in 17/29 (59%), 15/29 (51%) and 13/29 (45%) patients respectively. Only 7/29 (24%) showed no neurological sequelae. Severity of deficits was not correlated with birth date but to age at bleeding. Older children showed a better neurological outcome than neonates. CONCLUSION: The frequency and outcome of ICH in haemophiliacs have not changed in our cohort over the past 20 years. Trauma at birth is an important risk factor for ICH in patients with haemophilia A or B. Intracranial haemorrhages in older children are rare, and a better outcome may be expected.

Brain hemangiomas of infancy. Sonographic detection and follow-up.

Vascular birthmarks of the skin can be associated with hemangiomas or arteriovenous malformations of different organs. Computed tomography and magnetic resonance imaging (MRI) combined with angiography are the diagnostic tools used in children, adolescents, and adults to depict vascular malformation or bleeding. In infants, ultrasound examination through the anterior fontanelle is possible. This report describes 2 mature infants with brain hemangiomas primarily detected by real-time sonography: In both the brain lesions were associated with cutaneous and other vascular birthmarks. MRI was used to verify the brain hemangiomas. Subsequent follow-up evaluations during therapy were easily performed by ultrasonography.

Inherited defects of the protein C anticoagulant system in childhood thrombo-embolism.

Childhood thrombo-embolism is mostly the result of inherited thrombophilia or vascular insults combined with risk factors such as peripartal asphyxia, fetopathia diabetica, exsiccosis, septicaemia, central lines, congenital heart disease, cancer, trauma, surgery or elevated antiphospholipid antibodies. Inherited thrombophilia includes mainly defects of the protein C pathway, resistance to activated protein C, protein C or protein S deficiency. Resistance to activated protein C, in the majority of cases caused by the point mutation Arg 506 Gln of the factor V gene, has emerged as the most important hereditary cause of thrombo-embolism in adults and children. However, since an acquired risk of thrombo-embolic complications frequently masks the inherited deficiency in affected children, children with thrombo-embolism should have adequate laboratory evaluation for inherited coagulation disorders, especially the protein C pathway. Until more data on childhood thrombo-embolism are available, treatment recommendations will continue to be extrapolated from guidelines for adults.

Prenatal diagnosis in combined antithrombin and factor V gene mutation.

We report prenatal diagnosis in a family with combined antithrombin deficiency (type II heparin binding site) and factor V 506 Arg to Gln mutation. Both clinically unaffected parents are heterozygous for the antithrombin mutation, which results in a 99 Leu to Phe substitution, and the father is also heterozygous for the factor V gene defect. There is one daughter, homozygous for the antithrombin and heterozygous for the factor V mutations, who suffered a right-sided hemiparesis at the age of 4 months due to occlusion of the left middle cerebral artery and a large left sided infarct followed by further thromboembolic events. The family requested prenatal diagnosis and chorionic villi was sampled at 12 weeks gestation. The fetus was shown to be heterozygous for the antithrombin and factor V gene mutations, the same genotype as the unaffected father. No further intervention was considered necessary. To our knowledge this is the first report of prenatal diagnosis in antithrombin deficiency.

Homozygous antithrombin deficiency: report of two new cases (99 Leu to Phe) associated with arterial and venous thrombosis.

Inherited antithrombin deficiency is associated with an increased risk of thrombosis, primarily venous rather than arterial. Most affected individuals have inherited only a single copy of an abnormal antithrombin (AT) gene. Homozygously affected individuals, although rare, have a severe thrombotic history of early onset and often affecting the arteries. We report two new cases of type II HBS (heparin binding site) deficiency in which the propositi are homozygous for the previously reported mutation 99 Leu to Phe, and who have a severe thrombotic history. These cases are considered alongside existing homozygote and compound heterozygote cases.

(ATT) trinucleotide repeats in the antithrombin gene and their use in determining the origin of repeated mutations.

Two (ATT) trinucleotide repeat polymorphisms have been identified in the tails of Alu repeat elements in intron 5 of the antithrombin gene. The frequency and distribution of allele sizes for the Alu 5 and Alu 8 tail polymorphisms have been defined in a sample Caucasian population. The Alu 5 polymorphism has two alleles while that of Alu 8 has 10 alleles with a heterozygosity of 0.83. These polymorphisms have been used in combination with four previously described polymorphisms within the antithrombin gene to construct antithrombin gene haplotypes in the sample Caucasian population. Twenty-two different haplotypes were observed, with the Alu 8 polymorphism being particularly useful in subdividing the core haplotype based on the previously identified polymorphisms. The haplotype data were used to investigate the origin of repeat mutations within the antithrombin locus. We compared the haplotypes associated the mutant antithrombin genes in five families with the mutation 2759C-->T (L99F) and five families with the mutation 5381C-->T (R129Stop). The mutation 2759C-->T (L99F), which occurs within a non-CpG dinucleotide, was carried on a gene associated with an identical haplotype in each of the five families. The mutation 5381C-->T (R129Stop), a single base substitution within a CpG dinucleotide, was associated with at least two different haplotypes. The findings suggest a founder effect in the five families sharing the 2759C-->T (L99F) and at least two independent origins for the CpG dinucleotide mutation 5381C-->T (R129Stop).

High-dose intravenous immunoglobulins in the treatment of adolescent and adult HIV-infected hemophiliacs.

In children infected with human immunodeficiency virus (HIV) placebo-controlled trials with intravenous immunoglobulins have resulted in a significant reduction in morbidity; however, the results of small trials in adolescents and adults have been inconsistent. In this study 17 HIV-infected hemophiliacs aged 9-30 years were treated with monthly intravenous immunoglobulins for an average of 32 months. At the end of the study, 8 years after the HIV infection, three patients (18%) had progressed to the acquired immunodeficiency syndrome (AIDS), and the average decrease in CD4 cells was 81 cells/microliter per year. The natural history of HIV infection in hemophiliacs in this age group shows a manifestation rate of AIDS between 11% and 26% 6-8 years after seroconversion and an average yearly decrease in CD4 lymphocytes of 68-110 cells/microliters. In conclusion, we observed no difference either in the manifestation rate of AIDS or in prognostic markers in this small cohort of HIV-infected hemophiliacs treated for more than 30% of their latency period with intravenous immunoglobulins compared to the well-documented natural history of HIV-infected hemophiliacs. However, none of the patients developed severe bacterial infections during the study period.