Von Willebrand disease type 2M: Correlation between genotype and phenotype.

BACKGROUND: An appropriate clinical diagnosis of von Willebrand disease (VWD) can be challenging because of a variable bleeding pattern and laboratory phenotype. Genotyping is a powerful diagnostic tool and may have an essential role in the diagnostic field of VWD. OBJECTIVES: To unravel the clinical and laboratory heterogeneity of genetically confirmed VWD type 2M patients and to investigate their relationship. METHODS: Patients with a confirmed VWD type 2M genetic variant in the A1 or A3 domain of von Willebrand factor (VWF) and normal or only slightly aberrant VWF multimers were selected from all subjects genotyped at the Radboud university medical center because of a high suspicion of VWD. Bleeding scores and laboratory results were analyzed. RESULTS: Fifty patients had a clinically relevant genetic variant in the A1 domain. Median bleeding score was 5. Compared with the nationwide Willebrand in the Netherlands study type 2 cohort, bleeding after surgery or delivery was reported more frequently and mucocutaneous bleedings less frequently. Median VWF activity/VWF antigen (VWF:Act/VWF:Ag) ratio was 0.32, whereas VWF collagen binding activity/VWF antigen (VWF:CB/VWF:Ag) ratio was 0.80. Variants in the A3 domain were only found in two patients with low to normal VWF:Act/VWF:Ag ratios (0.45, 1.03) and low VWF:CB/VWF:Ag ratios (0.45, 0.63). CONCLUSION: Genetically confirmed VWD type 2M patients have a relatively mild clinical phenotype, except for bleeding after surgery and delivery. Laboratory phenotype is variable and depends on the underlying genetic variant. Addition of genotyping to the current phenotypic characterization may improve diagnosis and classification of VWD.

Iron refractory iron deficiency anemia: a heterogeneous disease that is not always iron refractory.

TMPRSS6 variants that affect protein function result in impaired matriptase-2 function and consequently uninhibited hepcidin production, leading to iron refractory iron deficiency anemia (IRIDA). This disease is characterized by microcytic, hypochromic anemia and serum hepcidin values that are inappropriately high for body iron levels. Much is still unknown about its pathophysiology, genotype-phenotype correlation, and optimal clinical management. We describe 14 different TMPRSS6 variants, of which 9 are novel, in 21 phenotypically affected IRIDA patients from 20 families living in the Netherlands; 16 out of 21 patients were female. In 7 out of 21 cases DNA sequencing and multiplex ligation dependent probe amplification demonstrated only heterozygous TMPRSS6 variants. The age at presentation, disease severity, and response to iron supplementation were highly variable, even for patients and relatives with similar TMPRSS6 genotypes. Mono-allelic IRIDA patients had a milder phenotype with respect to hemoglobin and MCV and presented significantly later in life with anemia than bi-allelic patients. Transferrin saturation (TSAT)/hepcidin ratios were lower in IRIDA probands than in healthy relatives. Most patients required parenteral iron. Genotype alone was not predictive for the response to oral iron. We conclude that IRIDA is a genotypically and phenotypically heterogeneous disease. The high proportion of female patients and the discrepancy between phenotypes of probands and relatives with the same genotype, suggest a complex interplay between genetic and acquired factors in the pathogenesis of IRIDA. In the absence of inflammation, the TSAT/hepcidin ratio is a promising diagnostic tool, even after iron supplementation has been given. Am. J. Hematol. 91:E482-E490, 2016. © 2016 Wiley Periodicals, Inc.

Practice guidelines for the diagnosis and management of microcytic anemias due to genetic disorders of iron metabolism or heme synthesis.

During recent years, our understanding of the pathogenesis of inherited microcytic anemias has gained from the identification of several genes and proteins involved in systemic and cellular iron metabolism and heme syntheses. Numerous case reports illustrate that the implementation of these novel molecular discoveries in clinical practice has increased our understanding of the presentation, diagnosis, and management of these diseases. Integration of these insights into daily clinical practice will reduce delays in establishing a proper diagnosis, invasive and/or costly diagnostic tests, and unnecessary or even detrimental treatments. To assist the clinician, we developed evidence-based multidisciplinary guidelines on the management of rare microcytic anemias due to genetic disorders of iron metabolism and heme synthesis. These genetic disorders may present at all ages, and therefore these guidelines are relevant for pediatricians as well as clinicians who treat adults. This article summarizes these clinical practice guidelines and includes background on pathogenesis, conclusions, and recommendations and a diagnostic flowchart to facilitate using these guidelines in the clinical setting.

The challenge of managing hemophilia A and STEC-induced hemolytic uremic syndrome.

BACKGROUND: The hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy leading to acute kidney injury in children. In most cases it is triggered by an infection caused by Shiga-like toxin-producing Escherichia coli (STEC). Endothelial damage plays a central role in the pathogenesis of disease. Hemophilia A is a genetic disorder leading to factor VIII (FVIII) deficiency, an important factor in the coagulation system. CASE: Here we describe a hemophilia A patient who developed HUS due to a STEC O26 infection. The patient developed not only acute kidney injury, but also severe gastro-intestinal and neurological complications. Increased amounts of recombinant FVIII (rFVIII) had to be administered during the acute phase of the disease to reach acceptable blood levels of FVIII, in order to control the hemorrhagic colitis and to prevent severe neurological complications. CONCLUSION: The patient's treatment schedule of rFVIII during the HUS period was a serious challenge, and we cannot exclude that it contributed to the severity of the HUS by enhancing the thrombotic microangiopathic process. The role of factor VIII administration in the severe outcome of this disease is discussed.

Long-term subcutaneous protein C replacement in neonatal severe protein C deficiency.

We describe here the case of a boy who presented 2 days after birth with purpura fulminans on his feet and scalp. Laboratory investigations revealed signs of disseminated intravascular coagulation. An underlying coagulation disorder was suspected, and therapy with recombinant tissue plasminogen activator, fresh-frozen plasma, and unfractionated heparin was started. On the basis of plasma protein C activity and antigen levels of 0.02 and 0.03 IU/mL, respectively, after administration of fresh-frozen plasma, a diagnosis of severe protein C deficiency was established, and therapy with intravenous protein C concentrate (Ceprotin [Baxter, Deerfield, IL]) was started. Because of difficulties with venous access, we switched to subcutaneous administration after 6 weeks. The precise dosing schedule for subcutaneously administered protein C concentrate is unknown. In the literature, a trough level of protein C activity at >0.25 IU/mL is recommended to prevent recurrent thrombosis. During 1 year of follow-up our patient frequently had protein C activity levels at <0.25 IU/mL. Clinically, however, there was no recurrent thrombosis, and we kept the dosage unchanged. This report highlights 2 important points: (1) subcutaneously administered protein C concentrate is effective in treating severe protein C deficiency; and (2) in accordance with previous studies, after the acute phase trough levels of protein C activity at >0.25 IU/mL may not be necessary to prevent recurrent thrombosis. However, further research on the dosing, efficacy, and safety of protein C concentrate for prophylaxis and treatment of severe protein C deficiency is needed.

[New causes of microcytic anaemia: hereditary disorders of iron homeostasis]. / Nieuwe oorzaken van microcytaire anemie: erfelijke stoornissen in de ijzerhomeostase.

Recently various new gene defects have been identified which explain some previously unknown causes of inherited microcytic anaemias. These defects are located in genes that encode for the cellular iron importing protein Divalent Metal Transporter 1 (DMT1), the iron exporting protein ferroportin, the mitochondrial enzyme glutaredoxin-5 and the hepatocyte membrane protein matriptase-2.

An unusual cause of atrial tachycardia in a young patient with lymphoma.

An 8-year-old girl who was recently diagnosed as having anaplastic large-cell lymphoma presented with atrial tachycardia and dilated cardiomyopathy, which is a contraindication for further treatment with cardio-toxic chemotherapy. After starting digoxin therapy, the dilated cardiomyopathy resolved. Repeated episodes of atrial tachycardia in this case were not caused by any common disorder but were due to mechanical stimulation by a central venous catheter. Central venous catheters are known to cause mainly ventricular arrhythmias. However, atrial tachycardia is a rare manifestation of arrhythmia due to mechanical stimulation of the heart by a central venous catheter, with potentially important cardiovascular consequences.

Longitudinal assessment of health-related quality of life in preschool children with non-CNS cancer after the end of successful treatment.

BACKGROUND: The aim of the study was to access Health Related Quality of Life (HRQoL) in preschool cancer survivors during the first 3 years of continuous remission after the end of successful treatment, and to identify predictors of HRQoL. PROCEDURE: Parent-reported HRQoL was assessed in 53 preschool children treated successfully for cancer, using the TAPQOL and compared with norm data. Longitudinal mixed models analyses were performed to investigate to what extent demographic and medical variables and parental psychological distress were predictive of HRQoL over time. RESULTS: Two months after the end of successful cancer treatment, survivors showed significantly (P < 0.01) more problem behavior and anxiety, and scored significantly worse (P < 0.01) on sleeping, motor functioning, positive mood and liveliness than the norm. One year after the end of treatment survivors still showed significantly (P < 0.01) more anxiety and worse motor functioning. The level of HRQoL in survivors had normalized 2 and 3 years after the end of treatment. Longer duration of treatment, bad prognosis and greater parental psychological distress were associated with worse scores on the Physical Component Score of the TAPQOL. Medical variables and parental psychological distress were not associated with the Mental Component Score. CONCLUSIONS: Survivors adjusted well to the cancer experience and HRQoL improved with time. Despite overall resilience in survivors over time, physical as well as psychosocial monitoring in follow-up is recommended. Standard aftercare should preferably include psychosocial screening, education, and counseling directed at both survivors and parents.

Psychosocial indicators of health-related quality of life in children with cancer 2 months after end of successful treatment.

The purpose of the study was to identify psychosocial correlates of Health-Related Quality of Life (HRQoL) in pediatric cancer patients after completion of cancer treatment. Multiple regression analyses were performed to predict self-reported HRQoL of 52 patients aged 8 to 15 years, and parent-reported HRQoL of 54 patients aged 1 to 5 years. Cognitive coping, family functioning, parental emotional reactions, communication about the disease, and several medical variables were included in the regression models. Better HRQoL was especially associated with more positive expectations of the further course of the disease and less frequent parental asking after disease-related emotions of the child. Interventions should include "positive thinking" as a coping strategy. Several other psychosocial variables were indicative of better HRQoL but further research is needed to confirm and to understand the relationship between psychosocial variables and HRQoL.

Health-related quality of life in children and emotional reactions of parents following completion of cancer treatment.

BACKGROUND: Completing therapy is one of the major transitions in care in the practice of pediatric oncology and, therefore, deserves special consideration. The purpose of the study was to investigate health-related quality of life (HRQOL) of pediatric patients, and emotional reactions of their parents, shortly after the end of successful treatment. METHODS: HRQOL of 126 patients, aged 1-15 years, on average 2 months after the end of successful treatment, was assessed with the TNO-AZL Pre-school Quality of life Questionnaire and the TNO-AZL Children's Quality of life Questionnaire. Emotional adjustment of 124 mothers and 111 fathers was assessed with the General Health Questionnaire and the Situation Specific Emotional Reaction Questionnaire. The outcomes of the patients and parents were compared with norm data by means of one sample t-tests, one sample sign-tests or binomial tests. RESULTS: All age groups, except patients aged 8-11 years, experienced worse HRQOL than the norm with respect to motor functioning. In addition, pre-school patients were rated worse on sleeping, appetite, stomach, skin, problem behavior, anxiety, and liveliness, and patients aged 6-7 years on autonomy and cognitive functioning. Parents reported more psychological distress than the norm. Compared to parents whose children were 1-5 years after cancer treatment, they suffered more from feelings of loneliness, helplessness, and uncertainty. CONCLUSIONS: A few months after the end of successful cancer treatment, both patients and parents appeared to experience worse well-being than the norm to a clinically relevant extent. Supporting patients and parents should not stop when treatment ends.

Thirteen novel mutations in the factor VIII gene in the Nijmegen haemophilia A patient population.

The development of neutralising antibodies to factor VIII (FVIII) is a major complication of haemophilia A (HA) therapy. We aimed to construct an individual risk profile for the development of inhibitors in HA and started by screening for the causative mutation in our HA patient population. A total of 109 patients and 28 carriers were screened. The analysis revealed 38 different mutations in the FVIII gene, of which 13 have not been described on the Haemophilia A Mutation, Search, Test and Resource Site (HAMSTeRS). Twenty-five mutations have been reported previously and all except two had a similar phenotype to what has been described. Three novel mutations were associated with severe HA: one non-missense mutation, a small insertion in the A2 domain, and two missense mutations, a H256R mutation in the A1 domain and a L2025P substitution in the C1 domain. One novel mutation, Y156C, was associated with moderate HA. Nine novel mutations caused mild HA. The P130R, D167E and V278M mutations are located in the A1 domain. R439C, Y511H, A544G and Q645H in the A2 domain, L1758F in the A3 domain and a S2157R mutation in the C1 domain. In conclusion, the genotypic profile of our HA population was not different from others described and is suitable to study inhibitor formation.