Occurrence of hemophilia in the United States. The Hemophilia Surveillance System Project Investigators

Congenital bleeding disorders in Karachi, Pakistan

OBJECTIVE

To determine the frequency of inherited bleeding disorders, its complications, and treatment modalities available for its treatment.

DESIGN

Cross-sectional study.

PATIENTS AND METHODS

Patients with a history of bleeding tendency were tested for confirmation of the diagnosis. History and clinical findings were recorded. Laboratory analysis included prothrombin time (PT), activated partial thromboplastin time (APTT), bleeding time (BT), and fibrinogen assay. Patients with prolonged APTT were tested for factors VIII (FVIII) and IX (FIX). If FVIII was low, von Willebrand factor: antigen (vWF:Ag) and von Willebrand factor:ristocetin cofactor (vWF:RCo) were performed. When PT and APTT both were prolonged, FV, FX, and FII were tested. Platelet aggregation studies were done when there was isolated prolonged BT. Urea clot solubility test was done when all coagulation tests were normal. All patients with hemophilia A and B were evaluated for inhibitors.

RESULTS

Of the 376 patients, inherited bleeding disorder was diagnosed in 318 (85%) cases. Median age of patients was 16.4 years. Hemophilia A was the commonest inherited bleeding disorder that was observed in 140 (37.2%) followed by vWD 68 (18.0%), platelet function disorders 48 (12.8%), and hemophilia B in 33 (8.8%) cases. We also found rare congenital factor deficiencies in 13 (3.4%), low VWF in 11 (3.0%) participants and 5 (1.3%) in female hemophilia carriers. Hemarthrosis was the most frequent symptom in hemophilia A and B (79.7%) involving knee joint. Inhibitor was detected in 21 (15%) cases. Fresh frozen plasma/cryoprecipitate were the most common modality of treatment. In 58 patients, no abnormality was detected in coagulation profile.

CONCLUSION

Hemophilia A and vWD are the most common congenital bleeding disorders in this study. Hemarthrosis involving knee joint was the most common complication. Inhibitor was detected in a significant number of patients. Plasma is still the most common modality of treatment.

Systematic literature review of economics analysis on treatment of mild-to-moderate bleeds with aPCC versus rFVIIa

OBJECTIVE

Two bypassing agents, activated prothrombin complex concentrates (aPCC) and recombinant factor VIIa (rFVIIa), have shown similar efficacy and safety in the treatment of bleeding episodes in patients with hemophilia and inhibitors as demonstrated through the only two head-to-head clinical trials. Given the economic burden of bypassing treatment, it is crucial to have a valid estimate of cost effectiveness of alternative treatments. The aims of this study were to conduct a systematic review of published pharmacoeconomic literature on the cost-effectiveness of aPCC versus rFVIIa to treat mild-to-moderate bleeds in patients with hemophilia and inhibitors, with a focus on the model assumptions and their impact on results.

METHODS

An English language search was conducted for original economic studies comparing aPCC and rFVIIa published between 1995 and July 2010. Detailed information on sponsorship, study design, assumptions and their impact on results was collected for each study.

RESULTS

A total of 11 economic studies were included in the review. Nine studies assessed cost per bleeding episode (eight cost-minimization analysis (CMA) and one cost-effectiveness analysis (CEA)). Two studies were from longitudinal perspective. Studies on cost per bleeding episode were evaluated and systematically compared. All studies were from a third-party payer perspective. Most analyses, except one study, used a similar decision-tree model. The assumptions for all CMA studies were obtained from non-comparable single-armed trials or observational data. All studies were sponsored by the two competing manufacturers of rFVIIa (seven studies) and aPCC (two studies). The crucial parameter assumptions on treatment efficacy and dosing drove their reported findings. Eight of these nine studies favored their sponsor's product.

CONCLUSION

With one exception, published economic studies tend to favor their sponsor's product primarily by assuming a higher efficacy and lower dosing for the sponsored agent, even though the two existing head-to-head clinical studies do not support superior efficacy for either product.

Successful renal replacement therapy for a patient with severe hemophilia after surgical treatment of intracranial hemorrhage and hydrocephalus

A 21-year-old Japanese male with severe hemophilia A was developed end-stage renal failure. He was placed on combination therapy with peritoneal dialysis (PD) and hemodialysis (HD). Eight months later, he developed a hypertensive cerebral hemorrhage. After emergency surgery, he was managed with PD without HD to avoid cerebral edema. One month later, his renal replacement therapy was switched to HD (three times a week) from PD, since a ventriculoperitoneal shunt catheter was placed to treat his hydrocephalus. HD could be performed safety without anticoagulant agents on condition that factor VIII is given after every HD.

Perioperative and intraoperative maneuvers to optimize surgical outcomes in skull base surgery

There are many approaches to obtaining a workable endoscopic surgical field in sinus surgery. With extended sinus and transdural endoscopic surgery, a more rigid approach must be taken. There are 3 main factors that invariably lead to poor surgical outcomes in endoscopic sinus and skull base surgery: bleeding, inadequate access, and unidentified anatomic anomalies. Bleeding is arguably the most common reason for incomplete resection. An understanding of microvascular and macrovascular bleeding allows a more structured approach to improve the surgical field in extended endoscopic surgery. The endoscopic surgeon should always be comfortable in performing the same procedure as an open operation. However, converting or abandoning an endoscopic procedure should rarely occur because much of this decision making should take place preoperatively. Along with poor hemostasis, inadequate access is an important cause of poor outcome. Evaluation of the anatomy involved by pathology but also the anatomy that must be removed to allow adequate exposure is important. This article reviews the current techniques used to ensure optimal surgical conditions and outcomes.

The use of PEGylated liposomes in the development of drug delivery applications for the treatment of hemophilia

Hemophilia A is a rare X-linked bleeding disorder caused by lack or dysfunction of coagulation factor VIII (FVIII). Hemophilia A is treated with replacement therapy, but frequent injections of the missing FVIII often lead to the formation of inhibitory antibodies. Patients who develop high levels of inhibitors must be treated with bypassing agents such as activated FVII (FVIIa). Both FVIII and FVIIa have short half-lives and require multiple injections. Long-acting forms of these proteins would therefore reduce the frequency of injections, improve patient compliance and reduce complications. In this article we present a new platform technology that produces long-acting forms of FVIII and FVIIa and improves the efficacy of hemophilia treatment. This technology is based on the binding of proteins/peptides to the outer surface of PEGylated liposomes (PEGLip). Binding is dependent on an amino acid consensus sequence within the proteins and is highly specific. At the same time, binding is non-covalent and does not require any modification of the therapeutic agent or its production process. Association of proteins with PEGLip results in substantial enhancements in their pharmacodynamic properties following administration. These improvements seem to arise from the association of formulated proteins with platelets prior to induction of coagulation.

Replacement therapy with recombinant factor IX. A multicentre evaluation of current dosing practices in Italy

BACKGROUND

The in vivo recovery of recombinant factor IX (rFIX) is reported to be lower than that of plasma-derived products, with potential clinical implications for dosing. In clinical practice, a conversion (augmentation) factor is suggested to calculate the necessary doses of rFIX. The aim of this study was to assess the range of values for the conversion factor in usual clinical practice in Italy.

MATERIALS AND METHODS

The study was questionnaire-based and proposed to all Italian Haemophilia centres treating patients with haemophilia B. Age, weight, dosage used in the last effective infusion, treatment regimen (prophylaxis versus on-demand), human immunodeficiency virus (HIV) and hepatitis C virus (HCV) status, and years of previous therapy with rFIX were recorded for patients with severe haemophilia B treated with rFIX. Mean, standard deviation, median and range were calculated for demographic and treatment data for the overall population and for subgroups. The conversion factor for the theoretical dosage of 40 IU/Kg was calculated.

RESULTS

Among 207 patients with severe haemophilia B being followed in 24 centres, 138 (66.7%) were being treated with rFIX. The sample of 207 patients represents 83.1% of the population of Italian patients with severe haemophilia B. The age range of the studied patients was 0-72 years (mean, 24 years) and the weight range was 3-108 kg (mean, 60 kg). Nineteen patients (14.4%) were positive for HIV and 51 (42.9%) were positive for HCV. The mean dosage of rFIX was 44 IU/Kg, with no significant difference between those receiving the product as prophylaxis or on-demand. A reduction in dosage was observed with increasing age (0.23 IU/kg/year). The mean value for the conversion factor was 1.10 ± 0.36 (median 1.00, range 0.51-2.08), when estimated for the whole population. No effect of HIV and HCV status was found on the dose prescribed. No evident correlation was found with the underlying genetic mutation.

DISCUSSION

We found that dosing of rFIX in clinical practice is very close to that of plasma-derived FIX concentrates. As a consequence, dosing in the non-surgical setting should be started using the same criteria as those for plasma-derived FIX and treatment effectiveness verified on a clinical basis rather than relying on in vivo recovery assessments.

Burden of disease resulting from hemophilia in the U.S

BACKGROUND

Hemophilia is a hereditary bleeding disorder. Its complications can result in substantial morbidity, but few efforts have been made to quantify the disease burden.

PURPOSE

The objective of this analysis was to estimate the burden of disease due to hemophilia (A and B) in the U.S., using disability-adjusted life years (DALY).

METHODS

The approach taken by the WHO in its Global Burden of Disease study was followed. Assumptions were drawn from published literature, and population estimates from the U.S. Census Bureau for the Year 2007 were used. Estimations of years of life lost resulting from mortality (YLL) and years of life lost resulting from morbidity (YLD) were done separately by gender, 5-year age intervals, and severity of disease (morbidity only) with their sum representing DALYs. Disability weights were derived from the quality-of-life tool EuroQol (EQ-5D). The stability of burden estimates was tested by performing sensitivity analyses, changing one assumption at a time.

RESULTS

In the U.S. in 2007, hemophilia resulted in 110,095 DALYs, composed of 13,418 YLLs and 96,677 YLDs. Large differences between men/boys (107,346) and women/girls (2749) were observed, given that females are genetic carriers of the disorder and rarely present with disease. Sensitivity analyses revealed a relatively robust estimate with a maximum variation of 4.49%.

CONCLUSIONS

This first estimate of hemophilia-related DALYs in the U.S. indicates that control of hemophilia can potentially result in a gain of 1 healthy year of life for every 2700 people in the population.

Blood disorders among women: implications for preconception care

The objectives of preconception care for women with blood disorders are to provide women and their partners with information on the implications of blood disorders for pregnancy; reproductive choices; and the management of potential or future pregnancies. Advances in hematology have led to improved diagnosis and treatment of blood disorders, thereby contributing to longevity and quality of life for women who are either affected by or are carriers of blood disorders. Women with blood disorders pose unique challenges: physiologic events such as pregnancy and menstruation influence the manifestations of blood disorders; blood disorders are a risk factor for adverse pregnancy outcomes; pregnancy imposes the risk of potential genetic transmission of the blood disorder to the offspring;and medications used for treatment of blood disorders pose additional challenges to conception and pregnancy. Hence, it is crucial that women of childbearing age with blood disorders be provided proper care for their conditions and be counseled before they become pregnant, in time to prevent complications to mothers and infants related to blood disorders. The purpose of this paper is to provide a brief overview of the current knowledge related to blood disorders in women of reproductive age, the interventions needed to manage these conditions, and the implications of these conditions and their management for the health of women and their infants.

The public health response to blood disorders

Nonmalignant blood disorders meet all criteria for qualifying, as a group, as a very important public health problem with serious morbidities affecting over 1 million Americans every year, not including an additional 8 million individuals suffering from anemia. Many of these conditions and the morbidities and mortalities associated with them are, to a large extent, preventable. Further, the changing demographic composition of the American population is sure to increase the number of individuals affected by these conditions. Yet, nonmalignant blood disorders have not been recognized as important public health priorities. Immediate action is needed to meet the increasing challenge of blood disorders in public health. We propose a national, comprehensive, organized, coordinated, institutionalized, sustainable public health response to blood disorders based on the three core functions and the ten essential services of public health. Immediate action needs to be taken to improve surveillance and monitoring, increase public and provider awareness, increase the use of evidence-based practices, and enhance epidemiologic research on the causes, prevention, and treatment of conditions resulting in adverse outcomes.

Haemophilia in Spain

To determine the prevalence of haemophilia A and B and their complications in Spain, and to characterize the health care network providing support to haemophiliac patients. The study examines clinical and genetic characteristics, treatment options, and complications observed during the course of the disease. Cross-sectional multi-centre study. The study population were patients with HA and HB in active follow-up at any Spanish hospital by December 2006. We studied 2400 haemophiliacs, 2081 (86.7%) HA and 319 (13.3%) HB patients. Illness was severe in 32.3% of patients, moderate in 16.4%, and mild in 51.3%. Genetic screening was carried out in 32.6% of the patients. Treatment administered in 2006 consisted of coagulation factor concentrates in 60% of patients. Until December 2006, 45.8% of severely ill patients were taking prophylaxis. The mean number of bleeding episodes in 2006 was four for patients not receiving primary prophylaxis and 1.3 for those taking primary prophylaxis. Thirty percent of patients had established haemophiliac arthropathy in at least one joint; 16.8% of patients were HIV-infected and 34.8% HCV-infected. Inhibitors were detected in 10% of severe HA patients and in 6.5% of severe HB patients. Immune tolerance induction therapy was started in 34 patients. This is the first comprehensive study on the epidemiology of haemophilia in Spain. It will enable us to draw comparisons with neighbouring countries, to assess the quality of care provided to haemophiliacs in Spain, and to provide evidence-based guidance for the even provision and improvement of such care.

Malignancy in patients with haemophilia: a review of the literature

Haemophilia A and B are rare X-linked conditions. Elevated rates of HIV and hepatitis C related malignancies in these patients are well reported, however rates of other types of cancers are not. Therefore, a retrospective literature review of cancer in patients with haemophilia was conducted. A Medline search of articles from January 1966 to July 2009 utilizing the keywords haemophilia, leukaemia, malignancy, mortality, neoplasm and cancer was performed. The articles were reviewed and additional relevant publications were located from the references. Data on age, type and severity of haemophilia, HIV status, type of malignancy and outcomes were recorded as available. Thirty-two cases of leukaemia were identified as well as 159 malignant solid tumours. Specific incidence and prevalence rates could not be calculated due to the limited nature of the information available in the reports. Many types of malignancy have been reported in persons with haemophilia irrespective of infection with HIV and hepatitis C yet prevalence and incidence rates compared to the general population remain unknown. Patients with haemophilia can manifest non infectious related malignancies and symptomatic patients should be evaluated accordingly.

Mosaicism and haemophilia

Mosaicism may affect the haemophilia phenotype. Well-known instances include chromosomal mosaicism due to aneuploidy and pseudo-mosaicism due to varying patterns of X-chromosome inactivation. Chromosomal mosaicism in a chimera is a potential source of phenotypic variation. Gene mosaicism is commonplace. Its pattern and effect depend on the stage of development at which a mutation occurs. Proven or possible genetic mosaicism is an important consideration when predicting the likelihood of transmission of haemophilia to a future generation.

A study of reported factor VIII use around the world

The effect of replacement therapy has significantly improved the morbidity and mortality of people with haemophilia A in high income countries, a recent socio-economic development as the availability of safe concentrates has been matched by a willingness for their provision through reimbursement. In the developing world, however, this state has not been achieved, primarily because of the low visibility of haemophilia coupled with its expense, leading to inadequate treatment with its sequelae of severe pain, joint deformities, arthropathy, disabilities, and even death in childhood or early adult life. The objective of this paper was to study the reported factor VIII (FVIII) use on a country-by-country basis. Data on the reported FVIII use for 104 countries were obtained from the Marketing Research Bureau, Inc. and the World Federation of Hemophilia. The results show that FVIII use varies considerably among countries, even among the wealthiest of countries. The use of FVIII concentrate increases as economic capacity increases; in addition, consumption of FVIII has been increasing at a greater rate in high income countries. Given these trends, there probably will be a global increase in FVIII concentrates usage. Such information is critical for national healthcare agencies to determine realistic budget priorities in planning for an increased allocation of resources required to improve the treatment of patients with haemophilia A. This information is also important for pharmaceutical manufacturers to adequately plan for increased production of FVIII concentrates.

A study of variations in the reported haemophilia A prevalence around the world

The objectives of this paper were to study the reported haemophilia A prevalence (per 100 000 males) on a country-by-country basis and address the following: Does the reported prevalence of haemophilia A vary by national economies? We collected prevalence data for 106 countries from the World Federation of Hemophilia (WFH) annual global surveys and the literature. We found that the reported haemophilia A prevalence varied considerably among countries, even among the wealthiest of countries. The prevalence (per 100 000 males) for high income countries was 12.8 +/- 6.0 (mean +/- SD) whereas it was 6.6 +/- 4.8 for the rest of the world. Within a country, there was a strong trend of increasing prevalence over time--the prevalence for Canada ranged from 10.2 in 1989 to 14.2 in 2008 (R = 0.94 and P < 0.001) and for the United Kingdom it ranged from 9.3 in 1974 to 21.6 in 2006 (R = 0.94 and P < 0.001). Prevalence data reported from the WFH compared well with prevalence data from the literature. Patient registries generally provided the highest quality of prevalence data. The lack of accurate country-specific prevalence data has constrained planning efforts for the treatment and care of people with haemophilia A. With improved information, healthcare agencies can assess budgetary needs to develop better diagnostic and treatment facilities for affected patients and families and work to ensure adequate supplies of factor VIII concentrates for treatment. In addition, this information can help manufacturers plan the production of concentrates and prevent future shortages.

Profiling of factor VIII mutations in Korean haemophilia A

Haemophilia A (HA) is an X chromosome-linked inherited bleeding disorder caused by heterogeneous mutations of coagulation factor VIII (FVIII). Although more than 900 mutations of FVIII gene are reported in the HAMSTeRS database, the mutation data regarding the FVIII gene in the Korean population is currently insufficient. The aim of this study was to profile the mutations of FVIII in Korean HA, 38 unrelated Korean HA male patients were examined. Peripheral blood samples were obtained from the patients. Long distance-PCR was performed for the identification of inversions in intron 22 and intron 1. Then gross exon deletion was examined to the inversion-negative patients by multiplex-PCR. Finally, direct sequencing was performed on exons 1-26, 5'- and 3'-UTR. We identified 33 mutations from the 38 patients. These included 15 inversions in intron 22 (39.5%), one inversion in intron 1 (2.6%), one gross exon deletion (2.6%), five deletions (13.2%), two insertions (5.3%), six missense (15.8%) and three nonsense mutations (7.9%). Mutation types for five patients (13.2%) were not identified in this study. We determined that the most common defect in FVIII in this study was an inversion mutation in intron 22; this is consistent with the findings of other studies. For the first time in Korean HA, a patient with intron 1 inversion was found. In addition, we report eight novel mutation types which never been reported in HAMSTeRS database. The mutation data in this study should prove useful as a reference for the diagnosis of HA and the detection of carriers in the Korean population.

Antihemophilic factor (recombinant) plasma/albumin-free method for the management and prevention of bleeding episodes in patients with hemophilia A

Hemophilia is a rare genetic bleeding disorder that, if not adequately controlled, is associated with life-threatening bleeding events and serious and costly complications, primarily from joint damage. The advent of effective clotting factor replacement therapy for patients with hemophilia is considered one of the foremost medical advances of the 20th century. The last 3 decades of experience in hemophilia care have witnessed the effectiveness of the care of patients with hemophilia within specialized comprehensive care centers, advances in factor replacement therapies, the benefits of prophylaxis over on-demand replacement therapy, and the role of aggressive management of joint disease to prevent dysfunction. Ongoing challenges, including the management of inhibitors to factor therapies and the consequences of thousands of patients with hemophilia becoming infected with human immunodeficiency virus and hepatitis C virus in the 1980s from contaminated plasma-derived factor concentrates, have highlighted the need for vigilance with respect to clotting factor product safety, access to care, and a full complement of choice of factor replacement therapies. Advate^® (antihemophilic factor [recombinant] plasma/albumin-free method [rAHF-PFM]) is the first recombinant factor VIII therapy manufactured without human or animal protein additives to eliminate the risk of pathogen transmission that could be carried by these additives. Preclinical studies established bioequivalence with recombinant antihemophilic factor (Recombinate^®), a product with 16 years of clinical experience. Currently licensed in 44 countries worldwide, rAHF-PFM has over 7 years of clinical research within 5 global studies supporting its safety and efficacy in the treatment of patients with hemophilia A.

Mosaics and haemophilia

Some mosaic conditions may affect the haemophilia phenotype. Well-known instances include chromosomal mosaicism because of aneuploidy and pseudo-mosaicism because of varying patterns of X-chromosome inactivation. Chromosomal mosaicism in a chimera is a potential source of phenotypic variation. Gene mosaicism is commonplace. Its pattern and effect depend on the stage of development at which a mutation occurs. Proven or possible genetic mosaicism is an important consideration when predicting the likelihood of transmission of haemophilia to a future generation. A mosaic is an individual who has two or more cell lines, genetically different with regard to chromosomes or genes. As techniques improve and studies accumulate, mosaics are being found to be more common than hitherto believed. Some mosaic conditions may affect the phenotype of haemophilia in males and of the carrier state in females. Cells may be mosaic with regard to chromosomes, as in some instances of aneuploidy, and in chimeras, and in females owing to the pattern of X-chromosome inactivation. Cells may be mosaic with regard to new gene mutations. The pattern of mosaicism depends upon the stage in embryogenesis or in germ-cell formation in which the mutation arose.

The North American Immune Tolerance Registry: contributions to the thirty-year experience with immune tolerance therapy

The North American Immune Tolerance Registry (NAITR) began in 1992 as a project of the ISTH Factor VIII/IX Subcommittee with the goal of further determining immune tolerance induction (ITI) practices in Canada and the United States. This retrospective registry study, published in 2002, was limited in its capacity to provide definitive answers to many unresolved ITI practice issues. Nonetheless, it played a role in developing guidelines for current ITI practice and in generating hypotheses that must now be examined through rigorous prospective data collection efforts. For haemophilia A, the logical next step has been the initiation of international prospective randomized studies of ITI outcome relative to factor VIII (FVIII) dose and purity for subjects with high titre inhibitors. Both trials will additionally provide platforms for translational study of the immunology of tolerance, a prelude to the next generation of safe and effective tolerizing strategies. For the less common problem of FIX inhibitor eradication, prospective randomized studies will not be a feasible way to confirm the NAITR observations. Coordinated international efforts will still be required to prospectively collect data on ITI outcome to document new potentially effective therapeutic strategies for inhibitor eradication. These registries will hopefully also serve to identify potential subjects for scientific studies of immunology of haemophilia B-related allergic phenomena, a devastating complication of FIX antibody development.

Registry of inherited coagulopathies in Brazil: first report

Inherited coagulopathies are bleeding disorders, which require treatment for life. Keeping an updated registry on these diseases is crucial for planning care, documenting prevalence of diseases and evaluating effectiveness of resources. We have analysed data from 26 treatment centres on coagulopathies in Brazil. Information included socio-demographic data, diagnosis of coagulopathies, severity of haemophilias A and B, presence and quantification of inhibitors in haemophilia, type of von Willebrand disease (VWD) and infection status for viral diseases. On 1 July 2007, there were 10 982 patients with inherited coagulopathies in Brazil, of which 6881 (62.7%) corresponded to haemophilia A, 1291 (11.7%) to haemophilia B, 2333 (21.2%) to VWD, 258 (2.4%) to other coagulopathies and 219 (2.0%) to undiagnosed bleeding disorders. Haemophilia A and B inhibitors were present in 9.9% and 1.9% of the patients, respectively. Human immunodeficiency virus infection was present is 6.5%, 4.8% and 1% of patients with haemophilia A, B and VWD, respectively. Hepatitis C virus infection was present in 34.9%, 29.7% and 12% of patients with haemophilia A, B and VWD, respectively. Infection by hepatitis B and human T-cell leukemia-lymphoma virus was also reported. This is the first report on the registry of patients with inherited coagulopathies in Brazil, supposed to be the third largest population of patients with haemophilia.

Phenotype, genotype, and worldwide genetic penetrance of LRRK2-associated Parkinson's disease: a case-control study

BACKGROUND

Mutations in LRRK2, the gene that encodes leucine-rich repeat kinase 2, are a cause of Parkinson's disease (PD). The International LRRK2 Consortium was established to answer three key clinical questions: can LRRK2-associated PD be distinguished from idiopathic PD; which mutations in LRRK2 are pathogenic; and what is the age-specific cumulative risk of PD for individuals who inherit or are at risk of inheriting a deleterious mutation in LRRK2?

METHODS

Researchers from 21 centres across the world collaborated on this study. The frequency of the common LRRK2 Gly2019Ser mutation was estimated on the basis of data from 24 populations worldwide, and the penetrance of the mutation was defined in 1045 people with mutations in LRRK2 from 133 families. The LRRK2 phenotype was defined on the basis of 59 motor and non-motor symptoms in 356 patients with LRRK2-associated PD and compared with the symptoms of 543 patients with pathologically proven idiopathic PD.

FINDINGS

Six mutations met the consortium's criteria for being proven pathogenic. The frequency of the common LRRK2 Gly2019Ser mutation was 1% of patients with sporadic PD and 4% of patients with hereditary PD; the frequency was highest in the middle east and higher in southern Europe than in northern Europe. The risk of PD for a person who inherits the LRRK2 Gly2019Ser mutation was 28% at age 59 years, 51% at 69 years, and 74% at 79 years. The motor symptoms (eg, disease severity, rate of progression, occurrence of falls, and dyskinesia) and non-motor symptoms (eg, cognition and olfaction) of LRRK2-associated PD were more benign than those of idiopathic PD.

INTERPRETATION

Mutations in LRRK2 are a clinically relevant cause of PD that merit testing in patients with hereditary PD and in subgroups of patients with PD. However, this knowledge should be applied with caution in the diagnosis and counselling of patients.

FUNDING

UK Medical Research Council; UK Parkinson's Disease Society; UK Brain Research Trust; Internationaal Parkinson Fonds; Volkswagen Foundation; National Institutes of Health: National Institute of Neurological Disorders and Stroke and National Institute of Aging; Udall Parkinson's Disease Centre of Excellence; Pacific Alzheimer Research Foundation Centre; Italian Telethon Foundation; Fondazione Grigioni per il Morbo di Parkinson; Michael J Fox Foundation for Parkinson's Research; Safra Global Genetics Consortium; US Department of Veterans Affairs; French Agence Nationale de la Recherche.

Indirect carrier detection of canine haemophilia A using factor VIII microsatellite markers

A panel of factor VIII microsatellite markers was developed for indirect carrier detection of canine haemophilia A (factor VIII deficiency). A total of 78 dogs, representing 14 different breed variants of haemophilia A, were genotyped at six intragenic factor VIII marker loci. The markers spanned approximately 110 kb and were located in the 5' UTR of the factor VIII (F8) gene and within introns 6, 10, 12, 14 and 21. The observed heterozygosity (n = 39 females) for these markers was 0.675, 0.82, 0.868, 0.692, 0.473 and 0.775 respectively. The affected males of each breed variant had unique marker haplotypes. In addition, the marker haplotypes varied for two unrelated haemophilic Jack Russell terriers, compatible with independent mutation events causing haemophilia in different breeds and different families. A three-marker panel (markers within introns 6, 10 and 21) was informative for 37 of the 39 females. The haemophilia-associated haplotype was defined for six breed variants based on the genotypes of an affected male and a clear male sibling, with successful carrier detection of female siblings in each pedigree. Our results demonstrate an apparent allelic heterogeneity in canine haemophilia A; however, an indirect method based on a three-marker panel is feasible to facilitate carrier detection and genetic counselling.

Recombinant expression of coagulation factor VIII in hepatic and non-hepatic cell lines stably transduced with third generation lentiviral vectors comprising the minimal factor VIII promoter

BACKGROUND

Lentiviral vectors have the capacity to transduce stably non-dividing, differentiated and undifferentiated cells of various tissues, including liver. To obtain high-level expression of transgenes, vectors often rely on viral promoters. However, recent data suggest that the supraphysiologic expression from ubiquitous viral promoters may not be beneficial and harbor the risk of oncogene activation. Therefore this study explored the lentiviral-mediated expression of human coagulation factor VIII (FVIII) driven by the physiologic FVIII gene promoter (FVIII-p), the liver-specific human alpha-1-antitrypsin gene promoter (hAAT-p), the ubiquitous but non-viral EF1alpha promoter (EF1alpha-p) and the viral CMV promoter.

METHODS

Hepatic and non-hepatic cell lines were stably transduced with lentiviral vectors encoding FVIIIdelB and EGFP. To compare the different promoters, lentiviral vectors were cloned to drive FVIII expression from FVIII-p, EF1alpha-p, hAAT-p and CMV-p.

RESULTS

As expected, the strong viral CMV-p and the ubiquitous EF1alpha-p resulted in the highest FVIII expression in all cell lines tested (CMV-p 1.85 IU/mL/10(6) cells for 293T, 3.15 for HepG2, 5.03 for SK-Hep, 0.91 for Hepa1-6; EF1-alpha promoter 0.30 IU/mL/10(6) cells for 293T, 0.04 for HepG2, 2.75 for SK-Hep, 0.46 for Hepa1-6). While the hAAT-p resulted in low FVIII levels (0.10 IU/mL/10(6)cells in HepG2 and 0.04 in Hepa1-6), the FVIII promoter gave reasonable expression levels in hepatic cells (0.47 IU/mL/10(6)cells in Hepa1-6 and 0.44 in SK-Hep).

DISCUSSION

These results indicate the potential usefulness of the FVIII-p for hemophilia A gene therapy.

Prevalence of reduced fibrinogen binding to platelets in a population of Thoroughbreds

OBJECTIVE

To measure the frequency and magnitude of reduced fibrinogen binding in a population of horses from a Thoroughbred breeding farm.

ANIMALS

444 Thoroughbred horses, 1 to 27 years old, including 316 females, 72 geldings, and 56 sexually intact males.

PROCEDURES

Blood was collected from horses into tubes containingacid citrate dextrose adenine, and washed platelets were examined by use of flow cytometry for their ability to bind fibrinogen.

RESULTS

Data regarding fibrinogen binding to activated platelets were normally distributed, with nearly identical amounts of variation regardless of sex. In 3 horses, fibrinogen binding to platelets was reduced from 67.6% to 83.4%, compared with normal platelets, which indicated an inability of platelets to aggregate in response to thrombin (0.1 U/mL).

CONCLUSIONS AND CLINICAL RELEVANCE

Platelet fibrinogen binding of the affected horses identified in this study was characteristic of a reported heritable bleeding disorder in which the reduction in fibrinogen binding correlated with prolonged bleeding times in template bleeding assays. The bleeding disorder is distinct from Glanzmann thrombasthenia, in which platelets fail to bind fibrinogen because of lack of alphallb-beta3 integrin on their surface. The prevalence of affected horses within the small sample population studied here (0.7% [n = 3]) is considerably higher than the prevalence of bleeding disorders within more genetically diverse groups.

Incidence of inhibitors in a cohort of 838 males with hemophilia A previously treated with factor VIII concentrates

BACKGROUND

Development of an inhibitory antibody to factor VIII is currently the most serious complication of hemophilia A treatment. The rate of inhibitor development in those that have been previously treated with factor concentrates is poorly defined. Understanding the baseline rate of inhibitor development in the population of previously treated patients (PTPs) is important when evaluating the effect of exposure to new factor replacement products on inhibitor formation.

OBJECTIVES

To determine the rate of inhibitor development in PTPs with hemophilia A.

METHODS

A cohort of males with hemophilia A who had data collected on four or more occasions prior to 30 March 2003, as part of the Center for Disease Control and Prevention's Universal Data Collection Project, were eligible for inclusion in the cohort. Patients were included in the cohort if they had at least two Bethesda assay measurements and did not have an inhibitor prior to or at the start of the study period. The overall incidence rate was estimated as the number of verified incident inhibitor cases divided by the total follow-up time in years multiplied by 1000 (cases per 1000 person-years).

RESULTS

A total of 838 patients were included in the study. The overall incidence rate was calculated to be 2.14 cases per 1000 person years. All incident cases had more than 50 exposure days prior to inhibitor development.

CONCLUSIONS

Given the low rate of inhibitor development in PTPs with hemophilia A, small, non-randomized studies are inadequate to determine the rate of inhibitor development after exposure to novel products. Ongoing, standardized, postmarketing surveillance is needed to determine if novel factor products pose an increased risk of inhibitor development.

Coagulation Defects

The present understanding of the coagulation process emphasizes the final common pathway and the proteolytic systems that result in the degradation of formed clots and the prevention of unwanted clot formations, as well as a variety of defense systems that include tissue repair, autoimmune processes, arteriosclerosis, tumor growth, the spread of metastases, and defense systems against micro-organisms. This article discusses diagnosis and management of some of the most common bleeding disorders. The goals are to provide a simple guide on how best to manage patients afflicted with congenital or acquired clotting abnormalities during the perioperative period, present a brief overview of the methods of testing and monitoring the coagulation defects, and discuss the appropriate pharmacologic or blood component therapies for each disease.

[Relevance of early paediatric care for boys with severe haemophilia]

Major molecular and genetic findings over the last decades and subsequent applications for diagnosis and therapeutic concerns have dramatically improved the evolution of severe haemophilia in countries with high economic resources. Another major factor of progress consisted in the setting of comprehensive care centres coordinating the care at a regional level. The early involvement of paediatricians for this rare and potentially serious chronic disease, which may be symptomatic from birth, is relevant in this context. Indeed, the early diagnosis of severe haemophilia and the involvement of expert caregivers in a multidisciplinary approach, are essential to make the acceptance of the disease easier. The diagnosis announcement should go together with a therapeutic project, which is nowadays based on long-term prophylaxis. Awaiting for likely curative treatments in the future, such as gene therapy, early implementation of prophylaxis and observance of this gold standard treatment during all the period of growth are critical to prevent the haemophilic arthropathy, to favour the future social and work-related integration and overall to improve the quality of life. The occurrence of an inhibitor represents the major residual complication of replacement therapy, especially for young children with severe haemophilia A. Even though new therapeutic resources brought substantial improvements for inhibitor patients, a better understanding of risk factors is a key issue since more accurate replacement regimen might induce tolerance during the first exposures and subsequently might prevent this complication. Prophylaxis and inhibitors that represent major concerns in paediatric care of severe haemophilia are included as main research objectives for the national registry " FranceCoag Network".

Accommodating chromosome inversions in linkage analysis

This work develops a population-genetics model for polymorphic chromosome inversions. The model precisely describes how an inversion changes the nature of and approach to linkage equilibrium. The work also describes algorithms and software for allele-frequency estimation and linkage analysis in the presence of an inversion. The linkage algorithms implemented in the software package Mendel estimate recombination parameters and calculate the posterior probability that each pedigree member carries the inversion. Application of Mendel to eight Centre d'Etude du Polymorphisme Humain pedigrees in a region containing a common inversion on 8p23 illustrates its potential for providing more-precise estimates of the location of an unmapped marker or trait gene. Our expanded cytogenetic analysis of these families further identifies inversion carriers and increases the evidence of linkage.

Knowledge, attitudes, and behaviors of youths in the US hemophilia population: results of a national survey

OBJECTIVES

The National Hemophilia Foundation and the Centers for Disease Control and Prevention conducted a national survey focusing on knowledge about, attitudes toward, and behaviors associated with key prevention activities among youths with hemophilia and used the data gathered to design a health promotion campaign.

METHODS

A national, random sample of 459 patients was drawn from 20 hemophilia treatment centers and 8 hemophilia associations; 110 (24%) of the respondents were young people. A telephone questionnaire was used to measure knowledge, behaviors, and barriers to prevention.

RESULTS

Thirty-six percent of the youth respondents believed that joint disease cannot be prevented; 60% managed hemophilia by avoiding physical activity. Only 31% of the respondents treated bleeding episodes within 1 hour. Although hepatitis was a clear threat to this hemophilic cohort, 78% did now know transmission routes for hepatitis C, and 67% did not know transmission routes for hepatitis B.

CONCLUSIONS

Young people with chronic disorders need help understanding that they can prevent complications. We identified key messages for a hemophilia prevention campaign, including exercising to ensure healthy joints and treating bleeding episodes early and adequately.

Hemophilia: a practical approach to genetic testing

Hemophilia and von Willebrand disease together account for the large majority of congenital bleeding disorders. Contemporary management, including development of safer clotting factor concentrates and increased emphasis on long-term follow-up in comprehensive hemophilia centers, has improved both quality of life and longevity for patients with congenital bleeding disorders. In addition to facilitating development of recombinant clotting factor concentrates, isolation and characterization of the respective genes have led to increasing availability of a repertoire of genetic tests that, although expensive, are critical for appropriate genetic counseling of affected patients and their family members. This article provides a practical approach to using genetic testing for hemophilia A and B.

A model for a regional system of care to promote the health and well-being of people with rare chronic genetic disorders

People with rare, inherited chronic health conditions, such as hemophilia, face added physical, social, emotional, and fiscal challenges beyond those that are common to more prevalent chronic conditions. In 1975, a partnership among clinicians, consumers, and government agencies created a nationwide regional health delivery system that increased access to clinical care, prevention, and research, thereby improving health outcomes for people with hemophilia in the United States. Today, more than 130 Comprehensive Hemophilia Diagnostic and Treatment Centers in 12 regions serve 70%-80% of the nation's hemophilia patients. Health care leaders and advocates for other rare, expensive, chronic disorders may find that regionalization improves survival and reduces disability among affected populations. However, diverse and stable resources are needed to sustain such a model in our profit-oriented US health care arena.

Prevalence and risk factors for heart disease among males with hemophilia

There have been conflicting reports in the literature about the protective effect of hemophilia on the occurrence of ischemic heart disease (IHD). Circulatory disease has been reported as the second most common cause of death in persons with hemophilia in the United States. In addition to diabetes and hypertension, high levels of FVIII, as may occur during factor concentrate infusions, may increase IHD risk in this population. To estimate the prevalence of heart disease and examine factors associated with IHD and other heart diseases among persons with hemophilia, we analyzed data collected from the medical records of 3,422 males with hemophilia living in six U.S. states from 1993 to 1998. Heart disease cases were ascertained from among 2,075 persons who were hospitalized at least once during the 6-year period. Of these, 48 were diagnosed with IHD and 106, with other types of heart disease. The age-specific prevalence of IHD ranged from 0.05% in those under 30 years to 15.2% in those 60 years or older. Hospital discharge rates in males with hemophilia with IHD and other types of heart disease were lower compared to rates in age-matched U.S. males. In our cohort, as in the general population, IHD was independently associated with age, hypertension, diabetes, and hyperlipidemia. Other heart diseases were associated with HIV infection, hypertension, hemophilia B, and diabetes. In summary, persons with hemophilia have unique risk factors such as infusion of factor concentrates and infection with HIV that may predispose them to heart disease as their life expectancy increases.

Management of bleeding disorders in children

Diagnosis and management of congenital and acquired bleeding disorders in children requires not only an understanding of the unique characteristics of pediatric hemostasis but also the natural course of bleeding disorders in children, which may differ substantially from the course observed in adult patients. In this article, three bleeding disorders of great importance to the pediatric hematologist are reviewed: neonatal alloimmune thrombocytopenia (NAIT), hemophilia and immune-mediated thrombocytopenic purpura (ITP). Current aspects of management are outlined. The unique physiology of transplacental transfer of maternally derived anti-platelet antibodies can result in neonatal immune thrombocytopenia, a significant cause of morbidity and mortality from bleeding in affected infants. For patients with hemophilia, approaches to treatment have shifted over the past decade from on-demand therapy to prophylaxis, either primary of secondary, resulting in delay of onset or complete avoidance of hemophilic arthropathy. Hemophilic inhibitors often develop in young children, prompting the need for a thorough understanding of the use of bypassing agents as well as immune tolerance induction in the young child. Finally, although several management strategies for ITP of childhood have been shown to improve the platelet count, side effects associated with corticosteroids, IVIg, anti-D and splenectomy force the practitioner to also consider the option of carefully observing, but not treating, the child with ITP.

Recent advances in the management of the child who has hemophilia

This article discusses recent advances in the management of the child who has hemophilia.

Clinical and cost implications of target joints in Canadian boys with severe hemophilia A

OBJECTIVE

To compare target joint-associated costs incurred by boys with severe hemophilia A 1 year before and 1 year after development of a target joint (pre-TJ, post-TJ).

STUDY DESIGN

Resource utilization data were extracted retrospectively from medical and hemophilia clinic charts and patient diaries for 16 boys attending the Hospital for Sick Children (HSC)'s comprehensive care hemophilia program. Resources examined included drugs, medical care, hospitalization, laboratory tests, therapies, and transfusions received. All costs were figured using standard price lists and were discounted using an annual rate of 3%.

RESULTS

Fifteen of the 16 boys developed at least one target joint, defined as three bleeds into any single joint within a consecutive 3-month period, at an average age of 54 months (range, 15-94 months), with ankles being most often affected, followed by elbows and knees (46% vs 28% and 23%, respectively). The total cost of treating a boy with on-demand Factor VIII (FVIII) increased by 119% after development of a target joint, from $20,091 (in 2002 Canadian dollars [$CDN]) in the year before to $43,890 in the year after target joint development. Factor VIII use accounted for 87% of the total cost in the year before target joint development and 93% in the year after.

CONCLUSIONS

This study identified substantial increased costs of care associated with target joint development. This finding provides further support for more aggressive treatment aimed at reducing target joints-either more aggressive treatment of joint bleeds or institution of primary prophylactic therapy at an early age.