Factor 8 Gene Mutation Spectrum of 270 Patients with Hemophilia A: Identification of 36 Novel Mutations

Objective

Hemophilia A (HA) is the most severe X-linked inherited bleeding disorder caused by hemizygous mutations in the factor 8 (F8) gene. The aim of this study is to determine the mutation spectrum of the F8 gene in a large HA cohort from Turkey, and then to establish a phenotype-genotype correlation.

Materials and Methods

All HA cases (270 patients) analyzed molecularly in the Ege University Pediatric Genetics Molecular Laboratory between March 2017 and March 2018 were included in this study. To identify intron 22 inversion (Inv22), intron 1 inversion (Inv1), small deletion/insertions, and point mutations, molecular analyses of F8 were performed using a sequential application of molecular techniques.

Results

The mutation detection success rate was 95.2%. Positive Inv22 was found in 106 patients (39.3%), Inv1 was found in 4 patients (1.5%), and 106 different disease-causing sequence variants were identified in 137 patients (50.6%). In 10 patients (3.7%), amplification failures involving one or more exonic regions, considered to be large intragenic deletions, were identified. Of 106 different F8 mutations, 36 were novel. The relationship between F8 genotype and inhibitor development was considered significant.

Conclusion

A high mutation detection rate was achieved via the broad molecular techniques applied in this study, including 36 novel mutations. With regard to mutation types, mutation distribution and their impact on clinical severity and inhibitor development were found to be similar to those previously reported in other hemophilia population studies.

Effects of stem cell transplantation on bone mineral density and vitamin D status in children with thalassemia major

HSCT is a curative treatment in TM, but conditioning and immunosuppressive treatment may affect bone metabolism. In this retrospective study, we aimed to compare BMD, vitamin D status, and growth in children with TM who underwent HSCT to those in children with TD TM. Twenty-three children with TM who underwent HSCT (mean age 7.1 years [1.03-14.7]) and 24 children with TD thalassemia (mean age 9.8 years [1.6-14]) were recruited. Lumbar spine BMD of TD thalassemia patients was higher than those in patients who had HSCT at both baseline and second-year assessments (P=.009, P<.001, respectively). However, BMD Z scores or serum 25-OH vitamin D levels were not different in two groups. Being >10 years of age was a significant risk factor for low BMD, height, and weight Z score for both groups. Patients who underwent HSCT with Pesaro risk class II or III had higher risk for low BMD compared to those risk class I patients (P=.044). In conclusion, children with TM who were >10 years at HSCT are at risk for low BMD and growth retardation. HSCT had no effect on BMD deficit in children with TM.

Direct Antiglobulin Test Positivity in Children With Acute Lymphoblastic Leukemia at Diagnosis

Direct antiglobulin test positivity had been reported in the course of some lymphoproliferative neoplasms. However, there are a few case reports describing direct antiglobulin test (DAT) positivity in children with acute lymphoblastic leukemia (ALL). We herein report 8 patients who had positive DAT among 95 newly diagnosed children with ALL. None of these patients had evidence of hemolysis during the follow-up. An antibody was detected in 2 of 8 patients with positive DAT. These 2 children also had positive indirect antiglobulin test (IAT); an autoantibody that was reactive at 4°C, and an alloantibody (anti E) that was reactive at 37°C was detected. We believe DAT positivity in ALL without significant hemolysis is not a rare disorder, and a need for further prospective studies is apparent.

Evaluation of joint findings with gait analysis in children with hemophilia

BACKGROUNDS AND OBJECTIVES

Hemophilic arthropathy due to recurrent joint bleeding leads to physical, psychological and socioeconomic problems in children with hemophilia and reduces their quality of life. The purpose of this study was to evaluate joint damage through various parameters and to determine functional deterioration in the musculoskeletal system during walking using kinetic and kinematic gait analysis.

MATERIAL AND METHOD

Physical examination and kinetic and kinematic gait analysis findings of 19 hemophilic patients aged 7-20 years were compared with those of age, sex and leg length matched controls.

RESULTS

Stride time was longer in the hemophilia group (p=0.001) compared to the age matched healthy control group, while hip, knee and ankle joint rotation angles were more limited (p=0.001, p=0.035 and p=0.001, respectively). In the hemophilia group, the extensor moment of the knee joint in the stance phase was less than that in the control group (p=0.001). Stride time was longer in the severe hemophilia group compared to the mild-moderate hemophilia and control groups (p=0.011 and p=0.001, respectively). Rotation angle of the ankle was wider in the control group compared to the other two groups (p=0.001 for both). Rotation angle of the ankle joint was narrower in the severe hemophilia group compared to the others (p=0.001 for each). Extensor moment of the knee joint was greater in the control group compared to the other two groups (p=0.003 and p=0.001, respectively). Walking velocity was higher in the control group compared to the severe hemophilia group.

CONCLUSION

Kinetic and kinematic gait analysis has the sensitivity to detect minimal changes in biomechanical parameters. Gait analysis can be used as a reliable method to detect early joint damage.