Molecular characteristics of hereditary red blood cell membrane disorders in Thailand: a multi-center registry.

Red blood cell (RBC) membrane disorders represent a significant category of hereditary hemolytic anemia; however, information from Southeast Asia is limited. We established a national registry aiming to characterize RBC membrane disorders and their molecular features in Thailand. A total of 100 patients (99 kindreds) diagnosed with RBC membrane disorders between 2011 and 2020 from seven university hospitals were enrolled. The most prevalent disorders observed were hereditary elliptocytosis (HE; n=33), hereditary pyropoikilocytosis (HPP; n=28), hereditary spherocytosis (HS; n=19), Southeast Asian ovalocytosis (SAO; n=10 of 9 kindreds), and two cases of homozygous SAO. The remaining cases were grouped as unclassified membrane disorder. Seventy-six patients (76%) were molecularly confirmed by PCR, direct DNA sequencing, or hi-throughput sequencing. The primary causative gene for HE and HPP was SPTB, accounting for 28 out of 29 studied alleles for HE and 56 of 56 studied alleles for HPP. In the case of HS, dominant sporadic mutations in the ANK1 gene (n=4) and SPTB gene (n=3) were identified as the underlying cause. Notably, the four most common variants causing HE and HPP were SPTB Providence (c.6055 T>C), SPTB Buffalo (c.6074 T>G), SPTB Chiang Mai (c.6224 A>G), and SPTB c.6171__82delins TGCCCAGCT. These recurrent SPTB mutations accounted for 79 out of 84 mutated SPTB alleles (94%). In summary, HE and hereditary HPP associated with recurrent SPTB mutations are the predominant types of RBC membrane disorders observed in Thailand. These findings have significant implications for the clinical management and future research of RBC membrane disorders in the region.

Genetic analysis and molecular basis of G6PD deficiency among malaria patients in Thailand: implications for safe use of 8-aminoquinolines.

BACKGROUND: It was hypothesized that glucose-6-phosphate dehydrogenase (G6PD) deficiency confers a protective effect against malaria infection, however, safety concerns have been raised regarding haemolytic toxicity caused by radical cure with 8-aminoquinolines in G6PD-deficient individuals. Malaria elimination and control are also complicated by the high prevalence of G6PD deficiency in malaria-endemic areas. Hence, accurate identification of G6PD deficiency is required to identify those who are eligible for malaria treatment using 8-aminoquinolines. METHODS: The prevalence of G6PD deficiency among 408 Thai participants diagnosed with malaria by microscopy (71), and malaria-negative controls (337), was assessed using a phenotypic test based on water-soluble tetrazolium salts. High-resolution melting (HRM) curve analysis was developed from a previous study to enable the detection of 15 common missense, synonymous and intronic G6PD mutations in Asian populations. The identified mutations were subjected to biochemical and structural characterisation to understand the molecular mechanisms underlying enzyme deficiency. RESULTS: Based on phenotypic testing, the prevalence of G6PD deficiency (< 30% activity) was 6.13% (25/408) and intermediate deficiency (30-70% activity) was found in 15.20% (62/408) of participants. Several G6PD genotypes with newly discovered double missense variants were identified by HRM assays, including G6PD Gaohe + Viangchan, G6PD Valladolid + Viangchan and G6PD Canton + Viangchan. A significantly high frequency of synonymous (c.1311C>T) and intronic (c.1365-13T>C and c.486-34delT) mutations was detected with intermediate to normal enzyme activity. The double missense mutations were less catalytically active than their corresponding single missense mutations, resulting in severe enzyme deficiency. While the mutations had a minor effect on binding affinity, structural instability was a key contributor to the enzyme deficiency observed in G6PD-deficient individuals. CONCLUSIONS: With varying degrees of enzyme deficiency, G6PD genotyping can be used as a complement to phenotypic screening to identify those who are eligible for 8-aminoquinolines. The information gained from this study could be useful for management and treatment of malaria, as well as for the prevention of unanticipated reactions to certain medications and foods in the studied population.

Efficacy and Safety of a Dispersible Tablet of GPO-Deferasirox Monotherapy among Children with Transfusion-Dependent Thalassemia and Iron Overload.

The study aimed to determine efficacy and safety of generic deferasirox monotherapy. Deferasirox was administered in transfusion-induced iron overloaded thalassemia. Efficacy was defined as responders and nonresponders by ≤ 15 reduced serum ferritin from baseline. Adverse events were also monitored. Fifty-two patients with mainly Hb E/ß-thalassemia at the mean (SD) age of 8.7 (4.1) years, were enrolled. The mean (SD) daily transfusion iron load was 0.47 (0.1) mg/kg and maximum daily deferasirox was 35.0 (6.2) mg/kg. Altogether, 52, 40 and 18 patients completed the first, second and third years of study, respectively. The median baseline serum ferritin 2,383 ng/mL decreased to 1,478, 1,038 and 1,268 ng/mL at the end of first, second and third years, respectively, with overall response rate at 73.1% (38/52). Patients with baseline serum ferritin >2,500 ng/mL showed a change in serum ferritin higher than those ≤2,500 ng/mL starting from the 9th month of chelation. Adverse events were found in 5 of 52 patients (9.6%) including transaminitis (n = 2), one each of proteinuria, rash and proximal tubular dysfunction which resolved after transient stopping or decreasing the chelation dose. Generic deferasirox was effective and safe among pediatric patients with transfusion-induced iron overloaded thalassemia.

Recombinant Cas9 protein production in an endotoxin-free system and evaluation with editing the BCL11A gene in human cells.

Many therapeutic proteins are expressed in Escherichia coli bacteria for the low cost and high yield obtained. However, these gram-negative bacteria also generate undesirable endotoxin byproducts such as lipopolysaccharides (LPS). These endotoxins can induce a human immune response and cause severe inflammation. To mitigate this problem, we have employed the ClearColi BL21 (DE3) endotoxin-free cells as an expression host for Cas9 protein production. Cas9 is an endonuclease enzyme that plays a key role in the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR associated protein 9 (CRISPR/Cas9) genome editing technique. This technology is very promising for use in diagnostics as well as treatment of diseases, especially for genetic diseases such as thalassemia. The potential uses for this technology thus generate a considerable interest for Cas9 utilization as a therapeutic protein in clinical treatment. Therefore, special care in protein production should be a major concern. Accordingly, we expressed the Cas9 protein in endotoxin-free bacterial cells achieving 99% purity with activity comparable to commercially available Cas9. Our protocol therefore yields a cost-effective product suitable for invitro experiments with stem cells.

Effective T-cell replete haploidentical stem cell transplantation for pediatric patients with high-risk hematologic disorders.

OBJECTIVES: Patients with high-risk hematologic diseases require intensive modalities, including high-dose chemotherapy and allogeneic hematopoietic stem cell transplantation (allo-HSCT). Haploidentical T-cell-replete transplantation is a logical choice because of the limited availability of matched sibling donors and the prolonged time needed to identify matched unrelated donors in Thailand. METHODS: The clinical outcomes data of 43 patients undergoing allo-HSCT were reviewed. All patients had high-risk hematologic malignancies, were younger than 20 years, and were in complete cytological remission at the time of allo-HSCT. We used two different conditioning regimens: total body irradiation (TBI) combined with cyclophosphamide, fludarabine, and melphalan (n = 23) and thiotepa combined with fludarabine and busulfan (n = 20). All patients received a graft-versus-host disease prophylaxis regimen consisting of cyclophosphamide, mycophenolate mofetil, and a calcineurin inhibitor or sirolimus. RESULTS: There was no difference in engraftment between patients receiving either of the regimens. After a median follow-up of 35.8 (range, 0.6-106.2) months, the overall survival (OS) and event-free survival (EFS) rates were 62.4% and 54.7%, respectively. OS and EFS were comparable between the respective regimens. CONCLUSIONS: We conclude that thiotepa-based conditioning has similar efficacy and tolerability as TBI-based conditioning for haploidentical HSCT with post-transplant cyclophosphamide.

Thalassemia-related complications in pediatric, adolescent, and young adult patients with transfusion-dependent thalassemia: A multicenter study in Thailand.

INTRODUCTION: Management of transfusion-dependent thalassemia (TDT) can be challenging due to numerous potential disease-related complications and comorbidities in particular age groups. The objective of this study was to report thalassemia-related complications and risk factors in pediatric, adolescent, and young adult patients with TDT. METHODS: A multicenter web-based registry was conducted in patients with TDT aged 25 years and younger from eight university hospitals covering all parts of Thailand. Factors significantly associated with each complication were analyzed by logistic regression methods. RESULTS: Of 605 patients, 267 thalassemia-related complications were reported from 231 pediatric, adolescent, and young adult patients with TDT patients (38.2%). The most common complications were infections, followed by cholelithiasis and growth failure. Splenectomy and elevated pre-transfusion hemoglobin were statistically significant risk factors for infections (adjusted odds ratio [AOR] = 2.3, 95% confidence interval [CI]: 1.2-4.5, p-value = .01 and AOR = 1.5, 95% CI: 1.2-1.7, p-value < .005, respectively). There were two statistically significant risk factors conferred endocrinopathies, including older age (AOR = 1.06, 95% CI: 1.01-1.1, p-value = .01) and being male (AOR = 2.4, 95% CI: 1.4-4.0, p-value = .002). CONCLUSION: Nearly 40% of the patients in this cohort had thalassemia-related complications. Periodic surveillance and optimal care for respective complications may minimize comorbidities in pediatric, adolescent, and young adult patients with TDT.

Screening for ELANE, HAX1 and GFI1 gene mutations in children with neutropenia and clinical characterization of two novel mutations in ELANE gene.

BACKGROUND: Congenital neutropenia is a rare disease. Recurrent infections since young age are the presentation. The most common mutation causing severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) is the ELANE gene. The objectives of this study were to screen the three common genetic mutations of ELANE, HAX1 and GFI1 in children with chronic neutropenia and to describe the clinical characteristics of children who had the mutations. METHODS: Infants having ANC < 1,000/cu mm or children aged > 1 year having ANC < 1,500/cu mm at least 3 times in 3 months were enrolled in the study. Patients who had acquired neutropenia due to infection, immune deficiency, or drugs were excluded. The ELANE gene was first studied; and if mutations were not identified, the HAX1 and GFI1 genes were further examined. RESULTS: A total of 60 patients were enrolled in the study. The median (range) age, ratio of female to male, ANC, and last follow-up age were 9.2 (0.5-45.2) months, 1:1.2, 248 (0-1,101) /cu mm, and 19.9 (3.5-202.3) months, respectively. Infections were noted in 67.3% of all patients. ELANE gene mutation was found in only four patients (6.7%), and the rest (56 patients) showed no mutations in the HAX1 and GFI1 genes. In patients without mutations, 66.0% had normal ANC during the follow-up, with a median (range) age for normal ANC of 19.8 (4.0-60.0) months. Two novel mutations p. Ala79del (c.234_236del) and p. Val197GlufsTer18 (c.589_590insAGGCCGGC) were identified, and they respectively cause SCN and CyN. Patients with the two novel mutations presented with several episodes of infection, including pneumonia, sepsis, abscess, otitis media, and gum infection. CONCLUSION: The genetic screening for ELANE, HAX1, and GFI1 gene mutations in 60 patients with chronic neutropenia could identify four patients (6.7%) with ELANE gene mutation and two novel mutations, p. Ala79del in exon 3 and p. Val197GlufsTer18 in exon 4 causing SCN; and CyN, respectively.

Severity scoring system to guide transfusion management in pediatric non-deletional HbH.

BACKGROUND: Hemoglobin (Hb) H is generally recognized as mild thalassemia, despite its actual phenotypic diversity. A disease severity scoring system to guide initiation of regular transfusion among severely affected pediatric patients has not previously been reported. METHODS: Patients with HbH were classified into transfusion-dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT) as a surrogate for disease severity. Alpha-globin genotypes and relevant clinical parameters associated with TDT were identified. Univariate and multiple logistic regression analyses were performed to yield the most suitable severity scoring system. RESULTS: From 246 patients with a median age of 14.3 (interquartile range 9.9-18.4) years initially enrolled into the study, the chance of having severe disease and developing TDT was remarkable only among patients with non-deletional HbH, for whom the scoring system was developed. Univariate and multiple logistic regression analyses resulted in three retained parameters associated with TDT, ß-coefficients of which were used to develop the score. The final scoring system comprised age at diagnosis <2 years (score = 1), spleen size ≥3 cm (score = 1) and Hb at steady-state <7 (score = 4) or 7-8 g/dL (score = 3). A cutoff score ≥4 was associated with severe disease likely requiring regular transfusion (sensitivity 89.3%, specificity 81.4%), given regular transfusion resulted in maintained growth. The scoring system was validated in the second cohort of 77 non-deletional HbH, from which comparable sensitivity and specificity were obtained. CONCLUSION: The newly developed scoring system was practical and helpful to highlight severely affected pediatric non-deletional HbH patients with potential needs of regular transfusion. This can be used as a guide for optimal treatment and disease monitoring in the future.

Whole-exome sequencing uncovered genetic diagnosis of severe inherited haemolytic anaemia: Correlation with clinical phenotypes.

Next-generation sequencing has shed light on the diagnosis of previously unsolved cases of inherited haemolytic anaemia (IHA). We employed whole-exome sequencing to explore the molecular diagnostic spectrum of 21 unrelated Thai paediatric patients with non-thalassemic IHA, presenting hydrops fetalis and/or becoming transfusion-dependent for 1 year or more or throughout their lifespan. Anaemia was detected prenatally, within the first month and the fifth year of life in three, 12 and six patients respectively. Molecular diagnosis obtained from all patients revealed SPTB as the most frequently mutated gene (four reported, three novel), found in 31 of 42 studied alleles. The other two mutated genes identified were ANK1 (three novel) and KLF1 (two reported). Four recurring mutations within exon 29/30 (NM_001024858.2) accounted for the vast majority (90%) of mutated SPTB alleles, biallelic inheritance of which resulted in the most severe phenotypes: hydrops fetalis and life-long transfusion dependency. Dominant ANK1 (n = 3) and SPTB (n = 2) mutations and biallelic class 2 KLF1 mutations (n = 1) led to a shorter period of transfusion dependency. Our study demonstrated that mutated SPTB causing red-cell membranopathy is likely the most common cause of severe non-thalassemic IHA among Thai patients. This urges carrier screening in the population to prevent subsequent, severely affected births.

Red blood cell alloimmunization and other transfusion-related complications in patients with transfusion-dependent thalassemia: A multi-center study in Thailand.

BACKGROUND: Thalassemia is a common genetic disease in Southeast Asia. Red blood cell (RBC) transfusion is an essential treatment for severe forms of thalassemia. We performed a study to demonstrate RBC alloimmunization and other transfusion-related complications in patients with transfusion-dependent thalassemia (TDT). STUDY DESIGN AND METHODS: A multi-center web-based registry of TDT was conducted in eight medical centers across Thailand. Thalassemia information, transfusion therapy, and transfusion-related complications were collected. Factors associated with each complication were demonstrated using the logistic regression analysis. RESULTS: Of 1000 patients recruited for the study, 449 were males (44.9%). The mean age was 23.9 ± 15.4 years. The majority of patients, 738 (73.8%) had hemoglobin E/beta-thalassemia. In the study, 421 transfusion-related complications were reported from 357 patients (35.7%). Alloimmunization was the most common complication which was found in 156 patients (15.6%) with 284 positive antibody tests. The most frequent antibodies against RBC were anti-E (80/284, 28.2%) followed by anti-Mia (45/284, 15.8%) and anti-c (32/284, 11.3%). Age ≥3 years at initial blood transfusion, splenomegaly, higher frequencies, and volumes of transfusion were significant factors associated with alloimmunization. None of the patients had to terminate blood transfusion due to multiple alloantibodies. Other commonly seen complications were allergic reactions (130, 13.0%), autoimmune hemolytic anemia (70, 7.0%) and febrile non-hemolytic transfusion reaction (54, 5.4%). CONCLUSIONS: Transfusion-related complications, especially alloimmunization, were common among Thai patients with TDT. Extended RBC antigen-matching for the Rh system and Mia should be implemented to prevent the development of alloantibodies in multi-transfused patients.

A novel TCN2 mutation with unusual clinical manifestations of hemolytic crisis and unexplained metabolic acidosis: expanding the genotype and phenotype of transcobalamin II deficiency.

BACKGROUND: Transcobalamin deficiency is a rare inborn metabolic disorder, characterized by pancytopenia, megaloblastic anemia, failure to thrive, diarrhea, and psychomotor retardation. CASE PRESENTATION: We describe a patient who first presented at 3 months of age, with pancytopenia, hepatosplenomegaly, recurrent infection, metabolic acidosis, and acute hemolytic crisis. Extensive hematologic and immunologic investigations did not identify inherited bone marrow failure syndrome, acute leukemia or its related disorders. Whole exome sequencing identified a novel homozygous TCN2 mutation, c.428-2A > G and mRNA study confirmed an aberrant transcription of exon 4 skipping. The mutant protein is predicted to have an in-fame 51 amino acids deletion (NP_000346:p.Gly143_Val193del). The patient exhibited marked clinical improvement following hydroxocobalamin treatment. CONCLUSIONS: Transcobalamin deficiency should be investigated in infants with unexplained pancytopenia and acute hemolytic crisis with or without typical evidence of vitamin B12 deficiency.

Haploidentical Hematopoietic Stem Cell Transplantation in Thalassemia.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only established treatment that is potentially curative, but it is limited by the availability of donors and the medical condition of the patient. To expand the donor pool to include haploidentical related donors, we introduced a program consisting of a pharmacologic pre transplant immune suppression phase (PTIS) and two courses of dexamethasone (DXM) and fludarabine (FLU) followed by pre transplant conditioning with intravenous FLU busulfan (BU) and post transplant graft-vs.-host disease (GvHD) prophylaxis with cyclophosphamide (CPM), tacrolimus, and mycophenolate mofetil. We transplanted 83 consecutive transfusion-dependent patients with thalassemia; the 3-year projected overall and event-free survival is over 96.0%, and there have been no secondary graft failures. Of the first 31 patients, we had two graft failures, both of them occurring in patients with extremely high titers of anti-donor-specific human leukocyte antigen (HLA) antibodies [anti-donor specific antibodies (DSAs)], but after adjusting the PTIS to include bortezomib (BORT) and rituximab (RIX) for patients with high titers of anti-DSAs and using pharmacologic dose guidance for BU, we had no graft failures in the last 52 patients. Six (7.0%) of 83 patients developed severe GvHD. We conclude that this is a safe and efficacious approach to allogeneic HSCT in thalassemia.

Glucose-6-phosphate dehydrogenase mutations in malaria endemic area of Thailand by multiplexed high-resolution melting curve analysis.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy in humans, is prevalent in tropical and subtropical areas where malaria is endemic. Anti-malarial drugs, such as primaquine and tafenoquine, can cause haemolysis in G6PD-deficient individuals. Hence, G6PD testing is recommended before radical treatment against vivax malaria. Phenotypic assays have been widely used for screening G6PD deficiency, but in heterozygous females, the random lyonization causes difficulty in interpreting the results. Over 200 G6PD variants have been identified, which form genotypes associated with differences in the degree of G6PD deficiency and vulnerability to haemolysis. This study aimed to assess the frequency of G6PD mutations using a newly developed molecular genotyping test. METHODS: A multiplexed high-resolution melting (HRM) assay was developed to detect eight G6PD mutations, in which four mutations can be tested simultaneously. Validation of the method was performed using 70 G6PD-deficient samples. The test was then applied to screen 725 blood samples from people living along the Thai-Myanmar border. The enzyme activity of these samples was also determined using water-soluble tetrazolium salts (WST-8) assay. Then, the correlation between genotype and enzyme activity was analysed. RESULTS: The sensitivity of the multiplexed HRM assay for detecting G6PD mutations was 100 % [95 % confidence interval (CI): 94.87-100 %] with specificity of 100 % (95 % CI: 87.66-100 %). The overall prevalence of G6PD deficiency in the studied population as revealed by phenotypic WST-8 assay was 20.55 % (149/725). In contrast, by the multiplexed HRM assay, 27.17 % (197/725) of subjects were shown to have G6PD mutations. The mutations detected in this study included four single variants, G6PD Mahidol (187/197), G6PD Canton (4/197), G6PD Viangchan (3/197) and G6PD Chinese-5 (1/197), and two double mutations, G6PD Mahidol + Canton (1/197) and G6PD Chinese-4 + Viangchan (1/197). A broad range of G6PD enzyme activities were observed in individuals carrying G6PD Mahidol, especially in females. CONCLUSIONS: The multiplexed HRM-based assay is sensitive and reliable for detecting G6PD mutations. This genotyping assay can facilitate the detection of heterozygotes, which could be useful as a supplementary approach for high-throughput screening of G6PD deficiency in malaria endemic areas before the administration of primaquine and tafenoquine.

Hematopoietic Stem Cell Transplantation for Severe Thalassemia Patients from Haploidentical Donors Using a Novel Conditioning Regimen.

Patients with severe thalassemia commonly have a survival that is significantly shorter than that of the general population. Allogeneic hematopoietic stem cell transplantation (allo-SCT) is the only established treatment that is potentially curative, but it is limited by the availability of donors and the medical condition of the patient. To expand the donor pool to include haploidentical related donors, we introduced a program consisting of a pharmacologic pretransplant immune suppression phase (PTIS) and 2 courses of dexamethasone and fludarabine, followed by pretransplant conditioning with fludarabine-i.v. busulfan and post-transplant graft-versus-host disease (GVHD) prophylaxis with cyclophosphamide, tacrolimus, and mycophenolate mofetil. We transplanted 83 consecutive transfusion-dependent patients with thalassemia (median age, 12 years; range, 1 to 28 years) with a minimum follow-up of 6 months (median, 15 months; range, 7 to 53 months); the 3-year projected overall and event-free survival is over 96%, and there have been no secondary graft failures. Of the first 31 patients, we had 2 graft failures, both of them occurring in patients with extremely high titers of anti-donor-specific HLA antibodies (anti-DSAs), but after adjusting the PTIS to include bortezomib and rituximab for patients with high titers of anti-DSAs and using pharmacologic dose guidance for busulfan, we had no graft failures in the last 52 patients. Six (7%) of 83 patients developed severe GVHD. We conclude that this is a safe and efficacious approach to allogeneic SCT in thalassemia, yielding results comparable to those available for patients with fully matched donors.

UNC0638 induces high levels of fetal hemoglobin expression in ß-thalassemia/HbE erythroid progenitor cells.

Increased expression of fetal hemoglobin (HbF) improves the clinical severity of ß-thalassemia patients. EHMT1/2 histone methyltransferases are epigenetic modifying enzymes that are responsible for catalyzing addition of the repressive histone mark H3K9me2 at silenced genes, including the γ-globin genes. UNC0638, a chemical inhibitor of EHMT1/2, has been shown to induce HbF expression in human erythroid progenitor cell cultures. Here, we report the HbF-inducing activity of UNC0638 in erythroid progenitor cells from ß-thalassemia/HbE patients. UNC0638 treatment led to significant increases in γ-globin mRNA, HbF expression, and HbF-containing cells in the absence of significant cytotoxicity. Moreover, UNC0638 showed additive effects on HbF induction in combination with the immunomodulatory drug pomalidomide and the DNMT1 inhibitor decitabine. These studies provide a scientific proof of concept that a small molecule targeting EHMT1/2 epigenetic enzymes, used alone or in combination with pomalidomide or decitabine, is a potential therapeutic approach for HbF induction. Further development of structural analogs of UNC0638 with similar biological effects but improved pharmacokinetic properties may lead to promising therapies and possible clinical application for the treatment of ß-thalassemia.

No differences in hemostatic and endothelial activations between haploidentical and matched-donor hematopoietic stem cell transplantation in thalassemia disease.

Hemostatic changes and endothelial activations have been recognized in ß-thalassemic patients after matched-donor hematopoietic stem cell transplantation (HSCT) but there are limited studies for haploidentical HSCT. This report demonstrates that the levels of hemostatic and endothelial markers, including thrombin antithrombin complex, prothrombin fragment, D-dimer, von Willebrand factor antigen and thrombomodulin levels, were not significantly different between haploidentical and matched-donor HSCT patients.

An international registry of survivors with Hb Bart's hydrops fetalis syndrome.

Hemoglobin (Hb) Bart's hydrops fetalis syndrome (BHFS) resulting from α0-thalassemia is considered a universally fatal disorder. However, over the last 3 decades, improvements in intrauterine interventions and perinatal intensive care have resulted in increasing numbers of BHFS survivors. We have initiated an international registry containing information on 69 patients, of which 31 are previously unpublished. In this perspective, we analyze the available clinical information to document the natural history of BHFS. In the future, once we have accrued sufficient cases, we aim to build on this study and provide information to allow counseling of at-risk couples. To date, 39 patients have survived beyond the age of 5 years, 18 of whom are now older than 10 years. Based on the available cases, we find evidence to suggest that intrauterine therapy provides benefits during the perinatal and neonatal period; however, it may not provide additional benefits to long-term growth and neurodevelopmental outcomes. Growth retardation is a major adverse long-term outcome among BHFS patients with ∼40% being severely affected in terms of weight and ∼50% in terms of height. There is also an increased risk of neurodevelopmental delay as we find 20% (11/55) of BHFS survivors suffer from a serious delay of ≥6 months. Most patients in the registry require lifelong transfusion and often have associated congenital abnormalities and comorbidities. This perspective is a first step in gathering information to allow provision of informed counseling on the predicted outcomes of affected babies.

Increased endothelial activation in α-thalassemia disease.

One complication of thalassemia is thromboembolism (TE), which is caused by an abnormal red blood cell surface, as well as endothelial and platelet activation. These findings are commonly observed in severe ß-thalassemia. However, limited information on α-thalassemia exists. This study enrolled subjects with deletional and non-deletional α-thalassemia and normal controls (NC). Plasma and serum of subjects were tested for endothelial activation markers including thrombomodulin (TM), vascular cell adhesion molecule-1 (VCAM-1), and von Willebrand factor antigen as well as platelet activation markers including thromboxane B2 and platelet factor 4. A total of 179 subjects were enrolled: 29 in the deletional group (mean age 13.3 ± 4.4 years), 31 in the non-deletional group (mean age 12.9 ± 4.8 years), and 119 in the NC group (mean age 13.6 ± 3.0 years). Twenty nine percent of subjects in the non-deletional group received regular red blood cell transfusion and iron chelator administration. Serum ferritin level was higher in the non-deletional group than that in the deletional group. Multivariate analysis demonstrated that VCAM-1 and TM levels were increased significantly in α-thalassemia compared with NC group (816.8 ± 131.0 vs 593.9 ± 49.0 ng/ml, and 4.9 ± 0.7 vs 4.0 ± 0.4 ng/ml, P < 0.001 respectively). VCAM-1 and TM levels in the non-deletional group were significantly higher than that in the deletional group. The present study demonstrated endothelial activation in children with α-thalassemia disease, especially those in the non-deletional group, which might be one risk factor for TE in α-thalassemia disease.