The spectrum of bleeding in women and girls with haemophilia B

Nonsevere Hemophilia: The Need for a Renewed Focus and Improved Outcomes

People with nonsevere hemophilia (PWNSH) are phenotypically more diverse than those with severe hemophilia. Perceptions relating to a "nonsevere" phenotype have contributed to fewer research initiatives, fewer guidelines on optimal management, and a lack of standards for surveillance and clinical assessment for affected individuals. In many cases, episodes of abnormal bleeding could, if investigated, have led to earlier diagnosis. Furthermore, the major recent developments in therapy for hemophilia have largely focused on severe disease and, as a group, PWNSH have not been included in many key clinical trials. Benefiting people with severe disease, innovative replacement therapies have generally targeted factor levels that are above those present in a large proportion of PWNSH. Therapeutic advances can lead to improvement in phenotype for people with severe hemophilia over that currently experienced by many PWNSH. As a result, we are approaching a point where PWNSH may, in many countries, have a higher risk of bleeding and restriction in lifestyle than those with severe disease but with more limited therapeutic options. Given the multiple major advances in treatment for people with hemophilia, it is timely to review the aspects of nonsevere disease, to ensure equity in care and management for all individuals with this condition.

Bleeding risk in hemophilia A and B carriers: comparison of factor levels determined using chronometric and chromogenic assays

BACKGROUND

Predicting the bleeding risk in hemophilia A and B carriers (HAC, HBC) is challenging.

OBJECTIVE

The objectives of this study were to describe the bleeding phenotype in HAC and HBC using the standardized Tosetto bleeding score (BS); to determine whether the BS correlates better with factor levels measured with a chromogenic assay than with factor levels measured with chronometric and thrombin generation assays; and to compare the results in HAC and HBC.

METHODS

This ambispective, noninterventional study included obligate and sporadic HAC and HBC followed at a hemophilia treatment center between 1995 and 2019.

RESULTS AND CONCLUSION

The median BS (3, range 0-21 vs. 3.5, range 0-15, P  = ns, respectively) and the abnormal BS rate (35.6% vs. 38.2%, P  = ns) were not significantly different in 104 HAC and 34 HBC (mean age: 38 years, 6-80 years). However, some differences were identified. The risk of factor deficiency was higher in HBC than HAC. Specifically, Factor VIII activity (FVIII):C/Factor IX activity (FIX):C level was low (<40 IU/dl) in 18.3% (chronometric assay) and 17.5% (chromogenic assay) of HAC and in 47% and 72.2% of HBC ( P  < 0.001). Moreover, the FIX:C level thresholds of 39.5 IU/dl (chronometric assay) and of 33.5 IU/dl (chromogenic assay) were associated with very good sensitivity (92% and 100%, respectively) and specificity (80% for both) for bleeding risk prediction in HBC. Conversely, no FVIII:C level threshold could be identified for HAC, probably due to FVIII:C level variations throughout life.

Clinical Analysis and Mental Health Survey of Hemophilia Carriers: a Cross-sectional Study

OBJECTIVE

Hemophilia carriers (HCs), who are heterozygous for mutations in the clotting factor VIII/clotting factor IX gene (F8 or F9), may have a wide range of clotting factor levels, from very low, similar to afflicted males, to the upper limit of normal, and may experience mental health issues. The purpose of this study was to provide genetic information on mothers of hemophilia patients and to understand the clotting factor activity and phenotype of HCs. Additionally, we aimed to investigate the mental health status of HCs in China.

METHODS

A total of 127 hemophilia mothers, including 93 hemophilia A (HA) mothers and 34 hemophilia B (HB) mothers, were enrolled in this study. Long distance PCR, multiplex PCR, and Sanger sequencing were used to analyze mutations in F8 or F9. Coagulation factor activity was detected by a one-stage clotting assay. The Symptom Checklist 90 (SCL-90, China/Mandarin version) was given to HCs at the same time to assess their mental health.

RESULTS

A total of 90.6% of hemophilia mothers were diagnosed genetically as carriers, with inversion in intron 22 and missense mutations being the most common mutation types in HA and HB carriers, respectively. The median clotting factor level in carriers was 0.74 IU/mL (ranging from 0.09 to 1.74 IU/mL) compared with 1.49 IU/mL (ranging from 0.93 to 1.89 IU/mL) in noncarriers, of which 14.3% of HCs had clotting factor levels of 0.40 IU/mL or below. A total of 53.8% (7/13) of HA carriers with low clotting factor levels (less than 0.50 IU/mL) had a history of bleeding, while none of the HB carriers displayed a bleeding phenotype. The total mean score and the global severity index of the SCL-90 for surveyed HCs were 171.00 (±60.37) and 1.78 (±0.59), respectively. A total of 67.7% of the respondents had psychological symptoms, with obsessive-compulsive disorder being the most prevalent and severe. The pooled estimates of all nine factors were significantly higher than those in the general population (P<0.05).

CONCLUSIONS

The detection rate of gene mutations in hemophilia mothers was 90.6%, with a median clotting factor level of 0.74 IU/mL, and 14.3% of HCs had a clotting factor level of 0.40 IU/mL or below. A history of bleeding was present in 41.2% of HCs with low clotting factor levels (less than 0.50 IU/mL). Additionally, given the fragile mental health status of HCs in China, it is critical to develop efficient strategies to improve psychological well-being.

The effects of pathogenic and likely pathogenic variants for inherited hemostasis disorders in 140 214 UK Biobank participants

Rare genetic diseases affect millions, and identifying causal DNA variants is essential for patient care. Therefore, it is imperative to estimate the effect of each independent variant and improve their pathogenicity classification. Our study of 140 214 unrelated UK Biobank (UKB) participants found that each of them carries a median of 7 variants previously reported as pathogenic or likely pathogenic. We focused on 967 diagnostic-grade gene (DGG) variants for rare bleeding, thrombotic, and platelet disorders (BTPDs) observed in 12 367 UKB participants. By association analysis, for a subset of these variants, we estimated effect sizes for platelet count and volume, and odds ratios for bleeding and thrombosis. Variants causal of some autosomal recessive platelet disorders revealed phenotypic consequences in carriers. Loss-of-function variants in MPL, which cause chronic amegakaryocytic thrombocytopenia if biallelic, were unexpectedly associated with increased platelet counts in carriers. We also demonstrated that common variants identified by genome-wide association studies (GWAS) for platelet count or thrombosis risk may influence the penetrance of rare variants in BTPD DGGs on their associated hemostasis disorders. Network-propagation analysis applied to an interactome of 18 410 nodes and 571 917 edges showed that GWAS variants with large effect sizes are enriched in DGGs and their first-order interactors. Finally, we illustrate the modifying effect of polygenic scores for platelet count and thrombosis risk on disease severity in participants carrying rare variants in TUBB1 or PROC and PROS1, respectively. Our findings demonstrate the power of association analyses using large population datasets in improving pathogenicity classifications of rare variants.

The Molecular Basis of FIX Deficiency in Hemophilia B

Coagulation factor IX (FIX) is a vitamin K dependent protein and its deficiency causes hemophilia B, an X-linked recessive bleeding disorder. More than 1000 mutations in the F9 gene have been identified in hemophilia B patients. Here, we systematically summarize the structural and functional characteristics of FIX and the pathogenic mechanisms of the mutations that have been identified to date. The mechanisms of FIX deficiency are diverse in these mutations. Deletions, insertions, duplications, and indels generally lead to severe hemophilia B. Those in the exon regions generate either frame shift or inframe mutations, and those in the introns usually cause aberrant splicing. Regarding point mutations, the bleeding phenotypes vary from severe to mild in hemophilia B patients. Generally speaking, point mutations in the F9 promoter region result in hemophilia B Leyden, and those in the introns cause aberrant splicing. Point mutations in the coding sequence can be missense, nonsense, or silent mutations. Nonsense mutations generate truncated FIX that usually loses function, causing severe hemophilia B. Silent mutations may lead to aberrant splicing or affect FIX translation. The mechanisms of missense mutation, however, have not been fully understood. They lead to FIX deficiency, often by affecting FIX’s translation, protein folding, protein stability, posttranslational modifications, activation to FIXa, or the ability to form functional Xase complex. Understanding the molecular mechanisms of FIX deficiency will provide significant insight for patient diagnosis and treatment.

Women and girls with haemophilia and bleeding tendencies: Outcomes related to menstruation, pregnancy, surgery and other bleeding episodes from a retrospective chart review

Introduction

Women or girls with haemophilia (WGH) represent a group of female symptomatic carriers who experience bleeding events more frequently than non‐carriers. Bleeding events include spontaneous/traumatic bleeds and prolonged bleeding related to surgery, menstruation and pregnancy. Challenges for the treatment of WGH include lack of screening, diagnosis and treatment guidelines.

Aim

Evaluate clinical characteristics, haemostasis management and clinical outcomes regarding menstruation, childbirth, dental procedures, surgeries and other bleeding events in WGH.

Methods

A retrospective, non‐interventional review of medical records from WGH among three haemophilia treatment centres (HTCs) was conducted in the United States (2012–2018). Patients with ≥2 visits to the HTC and who had undergone intervention for haemostasis management with the outcome documented were included. Descriptive statistics were used.

Results

Of 47 women and girls included in the chart review (37 with factor VIII deficiency, 10 with factor IX deficiency), median age at diagnosis was 22.6 years. Approximately 79% (n = 37) were diagnosed with mild haemophilia. Events of interest were primarily managed by factor concentrates or antifibrinolytics. Most treatment approaches were successful across clinical scenarios, except for heavy menstrual bleeding being insufficiently controlled in 8 (57%) of the 14 patients who experienced it.

Conclusions

Bleeding events in WGH, such as excessive and prolonged bleeding during menstruation, demonstrate a unique burden and require specific medical intervention. These results highlight the importance of assessing the need for haemostasis management in WGH and may contribute to future prospective study designs.

"Everything was blood when it comes to me": Understanding the lived experiences of women with inherited bleeding disorders

INTRODUCTION

Despite the many symptoms that women with inherited bleeding disorders experience, no study has specifically sought to explore and understand the lived experiences of these women, nor the barriers to care that they may encounter. The primary objective of this study was to describe the lived experiences of women with inherited bleeding disorders.

METHODS

Inclusion criteria for study enrollment were the following: age ≥18 years, English speaking, and confirmed diagnosis of an inherited bleeding disorder. Women were recruited across Canada through identification by treating health-care providers and study members of the Canadian Hemophilia Society. Telephone interviews were conducted using a semi-structured interview style, transcribed verbatim, and analyzed using descriptive thematic analysis.

RESULTS

A total of 15 participants were interviewed. Median age was 31 years (24-70 years old). Four primary themes emerged: uncertainties surrounding diagnosis, conceptualization of experience through family bleeding, intensity of bleeding symptoms, and impact of bleeding on identity and daily life.

DISCUSSION

To our knowledge, this is the first study to thoroughly describe the experiences of adult women living with inherited bleeding disorders. We found that these women experience multiple uncertainties around their diagnosis. They conceptualize their bleeding by examining family histories; experience severe symptoms irrespective of their underlying diagnosis; and create identities around their bleeding symptoms, which influence multiple aspects of their life. Next study steps will involve sharing work specifically focused on treatment plans, barriers to care, and factors affecting care access.

Life expectancy and cause of death in individuals with haemophilia A and B in Norway, 1986-2018

OBJECTIVES

Evaluate trends over time in age- and cause of death in males with haemophilia (PWH) in Norway compared with the general male population and investigate its correlates with improvements in haemophilia treatment.

METHODS

Data about age and cause of death in the period of 1986-2018, from two independent, high-quality national registries: the Norwegian Cause of Death Registry (NCoDR) and the patient registry at Centre for Rare Disorders (CRD), Oslo University Hospital.

RESULTS

Life expectancy increased significantly from 1986 to 2018. However, PWH still had a decreased mean age at death of 56.8 years (SD = 24.7) in the NCoDR and 58.6 years (SD = 21.7) in the CRD data, compared with 73.9 years (SD = 16.3) in the general male population. There was a distinct shift in the most frequently reported haemophilia-related causes of death, such as haemorrhage and AIDS, to more age-related causes of death, such as cancer, reflecting an ageing population.

CONCLUSION

Haemophilia treatment has improved significantly in the last three decades. Despite treatment-related improvements, PWH in Norway still have a decreased life expectancy compared with the general male population.

The experiences and attitudes of hemophilia carriers around pregnancy: A qualitative systematic review

BACKGROUND

Hemophilia carriers (HCs) face specific psychosocial challenges related to pregnancy, caused by their inherited bleeding disorder. Optimal support from healthcare providers can only be realized by exploring medical and psychological healthcare requirements.

OBJECTIVE

To review all published evidence on the experiences and attitudes of HCs regarding reproductive decision-making, prenatal diagnosis, pregnancy, childbirth, and puerperium to provide an accessible overview of this information for health care providers.

STUDY SELECTION

Cochrane library, PubMed/MEDLINE, EMBASE, CINAHL, and PsycINFO were searched for original qualitative data. Two authors performed study selection, risk-of-bias assessment, data extraction, and data analysis through meta-summary. The extracted themes were discussed within the research team.

FINDINGS

Fifteen studies with an overall moderate quality were included. The following findings were identified: (a) Quality of life of family members with hemophilia influences reproductive decision-making; (b) Genetic counselling is generally considered useful; (c) The development of a specialized carrier clinic is considered valuable; (d) HCs describe prenatal diagnosis as beneficial yet psychosocially challenging; and (e) noninvasive prenatal diagnosis and preimplantation genetic diagnosis are predominantly considered beneficial. These findings are limited by the overall moderate quality of included studies and the possibly partly outdated results in the current era of hemophilia treatment.

CONCLUSIONS

Available qualitative literature on HCs around pregnancy focuses on genetic counselling and prenatal diagnosis. Future studies are needed on the experiences and needs of HCs through pregnancy and puerperium as well as in light of emerging hemophilia diagnosis and treatment options.