Challenges and knowledge gaps facing hemophilia carriers today: Perspectives from patients and health care providers

Genetic testing for children at risk to be hemophilia carriers

Carriers for hemophilia are at risk for bleeding despite normal or mildly reduced factor 8 or factor 9 activity levels. Genetic testing is necessary to determine carrier status in those at risk and early identification of carriers can inform their bleeding risk. The aims of this single-center retrospective study were to determine the uptake of genetic testing in children at risk to be hemophilia carriers and identify barriers to completion of testing. We identified 64 unique at-risk children assigned female sex at birth under 18 years old, with at least one caregiver participating in a visit between June 2019 and July 2023 with a genetic counselor with expertise in hemophilia. Of all those at risk, 27% (17/64) had undergone genetic testing prior to having genetic counseling at our center, at a median age of 5 years. Of those who had not yet had genetic testing (47/64): insurance prior authorization was initiated for 49% (23/47), testing was completed for 28% (13/47) at a median age of 11 years, and factor activity levels were known or drawn after the visit for 36% (17/47). The primary reason (14/24, 58%) for not initiating insurance prior authorization was not having a known family variant. Because carrier testing for X-linked disorders standardly involves targeted family variant testing rather than full gene testing, increasing the accessibility of carrier testing depends on increasing the accessibility and uptake of genetic testing in affected family members, usually individuals assigned male sex at birth, with a diagnosis of hemophilia. The impact of the decision to pursue genetic testing on current or future family members at risk to be carriers could be included in counseling discussions with individuals with hemophilia and their families.

Haemophilia testing of young girls in Canada: Describing the current recommendations for factor level and genetic testing and the experiences of Canadian parents

INTRODUCTION

It is widely acknowledged that haemophilia affects women and girls, yet current testing recommendations for factor level and genetic testing vary and do not universally incorporate updated research. Canadian parents have expressed frustration at inconsistent recommendations and reported instances where delayed testing led to missed diagnosis and preventable bleeding.

AIM

Study aim was to explore and describe the practice of haemophilia-related testing of young girls in Canada.

METHODS

A mixed methods study was carried out with two populations: (1) Nurses working in haemophilia care completed a survey regarding the current testing recommendations of their Haemophilia Treatment Centre (HTC), (2) Parents of obligate or potential haemophilia carriers completed a structured interview with questions about their family experience of haemophilia and testing decisions for daughters.

RESULTS

Twenty-six survey responses were received and showed wide variation in the usual recommendations of Canadian HTCs. Different factor level testing recommendations may be given to obligate and potential carriers despite no difference in bleeding risk. Only a minority of HTCs currently recommend an early baseline factor level (< 10 years) to obligate carriers (27%) or potential carriers (15%). For genetic testing of potential carriers, 70% of HTC would approve a family request for genetic testing of a minor with specific conditions. The majority of parents interviewed felt dissatisfied with their testing experience (58%) and highlighted many issues related to delayed testing recommendations.

CONCLUSION

Updated, nationally affirmed testing recommendations are needed that align with research on bleeding in women and girls affected by haemophilia.

Application of machine learning approaches for predicting hemophilia A severity

BACKGROUND

Hemophilia A (HA) is an X-linked congenital bleeding disorder, which leads to deficiency of clotting factor (F) VIII. It mostly affects males, and females are considered carriers. However, it is now recognized that variants of F8 in females can result in HA. Nonetheless, most females go undiagnosed and untreated for HA, and their bleeding complications are attributed to other causes. Predicting the severity of HA for female patients can provide valuable insights for treating the conditions associated with the disease, such as heavy bleeding.

OBJECTIVES

To predict the severity of HA based on F8 genotype using a machine learning (ML) approach.

METHODS

Using multiple datasets of variants in the F8 and disease severity from various repositories, we derived the sequence for the FVIII protein. Using the derived sequences, we used ML models to predict the severity of HA in female patients.

RESULTS

Utilizing different classification models, we highlight the validity of the datasets and our approach with predictive F1 scores of 0.88, 0.99, 0.93, 0.99, and 0.90 for all the validation sets.

CONCLUSION

Although with some limitations, ML-based approaches demonstrated the successful prediction of disease severity in female HA patients based on variants in the F8. This study confirms previous research findings that ML can help predict the severity of hemophilia. These results can be valuable for future studies in achieving better treatment and clinical outcomes for female patients with HA, which is an urgent unmet need.

Identifying hemophilia B carriers: Utility of aPTT, factor IX levels and ratios of factor IX to other Vitamin K dependent factors

INTRODUCTION

Diagnosing hemophilia B (HB) carrier status is important to manage bleeding in carriers and to prevent bleeding in potential offspring. Without a family history of hemophilia, diagnosing HB carrier status is challenging. Genetic testing is the gold-standard, however it is reserved for individuals with a high suspicion of carrier status.

AIMS

To describe the distribution of activated partial thromboplastin time (aPTT) and factor IX coagulant (FIX:C) levels in HB carriers and assess the ratio of FIX:C to other Vitamin K dependent factors (FII:C, FVII:C, FX:C) as an indicator of HB carrier status.

METHODS

In this retrospective, single-centre cohort study, subjects were included if they were obligate or genetically proven HB carriers. Distributions of aPTT and FIX:C were described and the relationship between FIX:C levels in carriers and severity of familial HB was analysed. Ratios of FIX:C to FII:C, FVII:C, FX:C were calculated.

RESULTS

Seventy-two female HB carriers (median age: 34 years; IQR 24-43) were included. Median aPTT and FIX:C levels were 33.0 s [IQR 30.0-37.0] and 57 IU/dL [IQR 43-74]. Fifteen carriers (21%) had mild HB (FIX:C levels of 10-40 IU/dL). FIX:C levels trended higher in carriers of mild HB versus carriers of moderate/severe HB. In six carriers, the median ratio of FIX:C to other Vitamin K dependent factors was 0.44, with 92% of ratios being ≤ 0.75.

CONCLUSION

aPTT and FIX:C levels were unreliable in diagnosing HB carrier status. A low ratio of FIX:C to other Vitamin K dependent factors may be a useful marker of HB carrier status.

Clinical and treatment characteristics of infants and toddlers less than 2 years of age with hemophilia

ABSTRACT

Infants and toddlers (ITs) with hemophilia have unique bleeding features. Factor prophylaxis has been shown to decrease the risk of intracranial hemorrhage (ICH), which supports recommendations to begin at a young age. Clinical and demographic characteristics were analyzed for 883 ITs ≤2 years old with hemophilia A and B, seen at US Hemophilia Treatment Centers and enrolled in the Community Counts Registry, a surveillance program of the Centers for Disease Control and Prevention. ICH in the first 2 years of life was seen in 68 of 883 (7.7%) ITs, of whom 8 of 68 (11.8%) were on continuous prophylaxis at the time of ICH. ITs in this study usually started prophylaxis within the first year of life (mean, 10.3 months), with earlier ages of prophylaxis initiation in later birth cohorts in ITs with hemophilia A. Compared with those without a family history (FH) of hemophilia, known positive FH of hemophilia was associated with earlier age of diagnosis (P ≤ .0001) and decreased rates of vaginal delivery (P = .0006). The use of factor VIII mimetics and extended half-life clotting factor prophylaxis increased with later birth cohorts for ITs with hemophilia A and B. The study highlights that ICH rates in ITs with hemophilia remains substantial and underscores the need for further research to identify modifiable risk factors to prevent ICH by earlier diagnosis and initiating prophylaxis early, even within the first month of 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.

Exploring Female Relatives of Patients with Hemophilia' Awareness, Attitudes, and Understanding Towards Genetic Testing

Purpose

A better understanding of the factors that influence engagement is needed to provide a reference for conducting genetic testing in female relatives of patients with hemophilia (PWH). We therefore determined the perceptions and understanding of genetic testing among female relatives of PWH in China.

Methods

We carried out a qualitative study using in-depth, semi-structured interviews with 11 female relatives of PWH in Shanxi Province, China. The resulting data were analyzed using thematic analyses.

Results

This study extracted four topics: uncertainty about carrier genetic status; limited understanding of genetic testing; coexistence of positive and negative coping; and multi-aspect demands.

Conclusion

Healthcare professionals should provide personalized and multidimensional health education and comprehensive decision-making support to female relatives of PWH, to enhance their motivation and willingness to undergo genetic testing. It is also important to actively improve relevant policies, strengthen the genetic testing service system, and promote the popularization of genetic testing in female relatives of PWH.

A Qualitative Study Exploring the Experiences and Perceptions of Patients with Hemophilia Regarding Their Health-Related Well-Being, in Salamanca

Hemophilia is a chronic, congenital/hereditary and X-linked disease, characterized by an insufficiency of factors VIII or IX, which are necessary for blood clotting. Those affected by hemophilia often suffer from particular psychosocial problems, both in the acceptance, coping, treatment and self-management of their disease and in their family and social relationships, which are often mediated by these circumstances. The aim of this study was to explore the experiences of people with hemophilia or their family members, of in a specific region of Spain, regarding the impact of having hemophilia. Structured interviews were conducted and developed, using the studies of the World Federation of Hemophilia and Osorio-Guzmán et al. as a guide, as well as a literature review of qualitative work on hemophilia. Data were analyzed using a six-step thematic analysis. A total of 34 interviews were thematically analyzed. The results showed that three key themes emerged from the data: (1) the daily impact of having hemophilia, (2) uncertainty about the disease, (3) the role of associations and (4) support from institutions. The results make it clear that the disease has a major impact on their lives (work, family, leisure and personal environment). The main conclusion is that hemophilia has a negative impact on the daily lives of patients, families and caregivers.