A 3-bp deletion in the HBS1L-MYB intergenic region on chromosome 6q23 is associated with HbF expression

Fetal hemoglobin (HbF) is regulated as a multigenic trait. By genome-wide association study, we confirmed that HBS1L-MYB intergenic polymorphisms (HMIP) and BCL11A polymorphisms are highly associated with HbF in Chinese β-thalassemia heterozygotes. In this population, the variance in HbF resulting from the HMIP is 13.5%; that resulting from the BCL11A polymorphism is 6.4%. To identify the functional variant in HMIP, we used 1000 Genomes Project data, single nucleotide polymorphism imputation, comparisons of association results across populations, potential transcription factor binding sites, and analysis of phylogenetic conservation. Based on these studies, a hitherto unreported association between HbF expression and a 3-bp deletion, between 135 460 326 and 135 460 328 bp on chromosome 6q23 was found. This 3-bp deletion is in complete linkage disequilibrium with rs9399137, which is the single nucleotide polymorphism in HMIP most significantly associated with HbF among Chinese, Europeans, and Africans. Chromatin immunoprecipitation assays confirmed erythropoiesis-related transcription factors binding to this region in K562 cells. Based on transient expression of a luciferase reporter plasmid, the DNA fragment encompassing the 3-bp deletion polymorphism has enhancer-like activity that is further augmented by the introduction of the 3-bp deletion. This 3-bp deletion polymorphism is probably the most significant functional motif accounting for HMIP modulation of HbF in all 3 populations.

A prospective study of symptomatic bacteremia following platelet transfusion and of its management

BACKGROUND

The danger of bacteremia due to contaminated platelets is not well known. There are also no established guidelines for the management of febrile reactions after platelet transfusion.

STUDY DESIGN AND METHODS

To determine the risk of symptomatic bacteremia after platelet transfusion, 3584 platelet transfusions given to 161 patients after bone marrow transplantation were prospectively studied. Platelet bags were routinely refrigerated for 24 hours after transfusion. Septic work-up was initiated for a temperature rise of more than 2 degrees C above the pretransfusion value within 24 hours of platelet transfusion or a temperature rise of more than 1 degree C that was associated with chills and rigor. Diagnosis of bacteremia after platelet transfusion was made only when the pairs of isolates from the blood and the platelet bags were identical with respect to their biochemical profile, antibiotic sensitivity, serotyping, or ribotyping.

RESULTS

Thirty-seven febrile reactions, as defined above, occurred. Bacteremia subsequent to platelet transfusion was diagnosed in 10 cases. There was a 27-percent chance (95% CI, 15-43%) that these febrile reactions represented bacteremia that resulted from platelet transfusion. For a subgroup of 19 patients with a temperature rise of more than 2 degrees C, the risk of bacteremia was 42 percent (95% CI, 23-64%). Septic shock occurred in 4 of the 10 bacteremic patients. A rapid diagnosis was possible because the involved bacteria were demonstrated by direct Gram stain of the samples taken from the platelet bags of all 10 patients.

CONCLUSION

Significant febrile reactions after platelet transfusion are highly likely to be indicative of bacteremia. Routine retention of platelet bags for subsequent microbiologic study was useful in the investigation of these febrile reactions. Empiric antibiotic therapy is indicated.

Disseminated mediastinal carcinoma with chromosomal translocation (15;19). A distinctive clinicopathologic syndrome

BACKGROUND

A case of disseminated mediastinal carcinoma probably of thymic origin is reported in a 5-year-old boy with an anterior mediastinal mass associated with superior vena cava obstruction, tracheal deviation, right malignant pleural effusion, and evidence of bone metastasis. The diagnosis was based on findings of radiologic localization, light and electron microscopic study, and immunohistochemistry. The patient received combination chemotherapy but died of progressive disease.

METHODS

Cytogenic study on the pleural fluid was attempted, and a literature search for similar chromosomal aberration was performed.

RESULTS

Cytogenetic study of tumor cells from the pleural fluid revealed a clonal chromosomal abnormality of t(15;19)(q12;p13.1). Two patients with similar disease were reported in the English literature; their clinical courses, immunohistochemical findings, and t(15;19) were almost identical to those of the patient reported in this study.

CONCLUSION

The authors suggest that this translocation may be specific to thymic carcinoma and may indicate a particularly aggressive form of the disease. Carcinomas are rare in children, so the chromosomal translocation may serve as a helpful marker for the diagnosis.

Quality of life in patients with transfusion-dependent thalassemia after hematopoietic SCT

In this cross-sectional study, we compared the quality of life (QOL) in transfusion-dependent thalassemic patients who survived matched sibling hematopoietic SCT (HSCT, n=24) with patients treated conventionally with transfusion and iron chelation (n=74). WHOQOL-BREF(HK) and PedsQL questionnaires were administered to patients aged >18 years and 5-12 years, respectively. Patients aged 12-18 years received both questionnaires. WHOQOL-BREF(HK) revealed post transplant patients rated overall health better than those treated conventionally (score 3.67 vs 3.06, P=0.01). They are less dependent on medical aids (3.87 vs 2.96, P=0.006), having higher activity level (4.00 vs 3.36, P=0.026) and better personal relationships (4.13 vs 3.69, P=0.014). Physical health domain score was better (75.20 vs 63.94, P=0.007). These differences remained significant after adjustment for comorbidities. PedsQL revealed post transplant patients rated better for running (3.53 vs 2.72, P=0.001) and sports (3.20 vs 2.64, P=0.038), even after adjustment for comorbidities, but were less satisfied for school absence to attend hospital (2.53 vs 3.29, P=0.03). Post transplant patients were significantly more likely to consider marriage (100 vs 75.7%, P=0.033), but not childbearing (66.7 vs 51.4%, P=0.28). In conclusion, transplanted thalassemic patients enjoy better QOL, mainly in physical health, compared with conventionally treated patients. This information is important to patients considering HSCT.

Treatment of impending tumor lysis with single-dose rasburicase

OBJECTIVE

To report the experience of using rasburicase as a single-dose treatment for childhood leukemia presenting with hyperuricemia.

CASE SUMMARIES

Three children with acute lymphoblastic leukemia presenting with hyperuricemia received rasburicase as a single intravenous dose just prior to the start of chemotherapy. This was followed by rapid reduction of serum uric acid levels within 24 hours, which remained low throughout induction therapy while allopurinol and hydration therapy without urinary alkalinization ensued. Subclinical tumor lysis was evidenced by the appearance of hyperphosphatemia and hypocalcemia in all cases and hyperkalemia in 1 patient. These abnormalities were transient, and each patient's renal function gradually improved from pretreatment baseline without requiring dialysis.

DISCUSSION

Our experience suggests that hyperuricemia in children at risk for tumor lysis can be managed with a briefer regimen of rasburicase than the recommended 5- to 7-day course.

CONCLUSIONS

A shorter course of rasburicase treatment, including single-dose injection, is feasible and will improve the cost-effectiveness profile of the otherwise expensive compound.

Peritoneal metastases after laparoscopic nephron-sparing surgery for localized Wilms tumor

A 2-year-old girl was referred for the management of the progression of her localized Wilms tumor. She had undergone laparoscopic nephron-sparing surgery for her right Wilms tumor 3 months earlier. Postoperative chemotherapy was commenced 6 weeks later. Subsequent computer tomographic evaluation 12 weeks postsurgery showed local recurrence and peritoneal tumors. These findings were confirmed at laparotomy. We report the first case of peritoneal tumor dissemination after laparoscopic nephron-sparing surgery for localized Wilms tumor.

Molecular diagnosis of severe combined immunodeficiency--identification of IL2RG, JAK3, IL7R, DCLRE1C, RAG1, and RAG2 mutations in a cohort of Chinese and Southeast Asian children

Severe combined immunodeficiencies (SCID) are a group of rare inherited disorders with profound defects in T cell and B cell immunity. From 2005 to 2010, our unit performed testing for IL2RG, JAK3, IL7R, RAG1, RAG2, DCLRE1C, LIG4, AK2, and ZAP70 mutations in 42 Chinese and Southeast Asian infants with SCID adopting a candidate gene approach, based on patient's gender, immune phenotype, and inheritance pattern. Mutations were identified in 26 patients, including IL2RG (n = 19), IL7R (n = 2), JAK3 (n = 2), RAG1 (n = 1), RAG2 (n = 1), and DCLRE1C (n = 1). Among 12 patients who underwent hematopoietic stem cell transplantation, eight patients survived. Complications and morbidities during transplant period were significant, especially disseminated bacillus Calmette-Guérin disease which was often difficult to control. This is the first cohort study on SCID in the Chinese and Southeast Asian population, based on a multi-centered collaborative research network. The foremost issue is service provision for early detection, diagnosis, management, and definitive treatment for patients with SCID. National management guidelines for SCID should be established, and research into an efficient platform for genetic diagnosis is needed.

Allogeneic stem cell transplantation for children with acquired severe aplastic anaemia: a retrospective study by the Viva-Asia Blood and Marrow Transplantation Group

We retrospectively analysed the outcomes of 127 children with acquired severe aplastic anaemia (SAA) who had received haematopoietic stem cell transplantation (HSCT) between 2000 and 2011 in one of the 10 Asia Pacific institutions. Fifty-three were matched sibling donor (MSD) and 74 were alternative donor (AD), including 22 matched unrelated donor, 32 mismatched unrelated donor and 20 mismatched related donor. With a median follow up 45.5 months (13-139) and when compared to the MSD group, AD recipients had more grade II-IV acute graft-versus-host disease (aGVHD; 14.3% vs. 32.8%, P = 0.029), but similar grade III-IV aGVHD (10.2% vs. 12.5%, P = 0.774), graft failure (GF) (15.1% vs. 15.5%, P = 0.658) and 5-year overall survival (90.6% vs. 83.7%, P = 0.251). As a source of stem cell, peripheral blood stem cells (PBSC) resulted in less GF (18% vs. 9.1% P = 0.013), similar grade II-IV aGVHD (28.1% vs. 17.4%, P = 0.258), chronic GVHD (25.8% vs. 29.3%, P = 0.822) and similar outcomes (89.7% vs. 82.4%, P =0.665) when compared to bone marrow (BM). In univariate analysis, GF (P < 0.001) and grade II-IV aGVHD (P = 0.009) were predictors of poor survival. In multivariate analysis, only GF was associated with poor survival (P = 0.012). The outcome of AD and PBSC HSCT were comparable to that of MSD and BM HSCT in the Asia Pacific region.

Variation and heritability of Hb F and F-cells among beta-thalassemia heterozygotes in Hong Kong

Enhanced fetal hemoglobin (Hb F) production can partially compensate for the lack of adult hemoglobin (Hb A) in patients with beta-thalassemia major or intermedia, and ameliorate the clinical severity of these diseases. To further elucidate factors governing Hb F levels, we evaluated demographic, clinical, laboratory, and genetic characteristics in 241 unrelated adult beta-thalassemia carriers in Hong Kong. They had wide variations in Hb F and F-cell numbers skewing toward higher levels. Individuals who coinherited the Xmn IT-allele in the (G)gamma-globin gene promoter had higher Hb F and more F-cells compared with those lacking the Xmn I T-allele. However, both groups exhibited a similarly wide spread of Hb F and F-cells. The correlation of Hb F and F-cells corresponded well to both linear and exponential models, suggesting multiple mechanisms for Hb F augmentation. The heritabilities of Hb F and F-cells were calculated in 66 families (111 parents who were beta-thalassemia carriers and 82 asymptomatic offspring) to be 0.7 to 0.9. The Xmn I polymorphism accounted for 9% of the Hb F and 13% of the F-cell heritabilities. These results suggest that these family members are well suited for genome wide association studies that will identify genetic loci regulating Hb F production, and likely novel pharmacological targets for reactivating Hb F production in adults.

A cross-sectional study of growth, puberty and endocrine function in patients with thalassaemia major in Hong Kong

METHODOLOGY

A cross-sectional study of growth, puberty and endocrine function was performed on 35 girls and 33 boys with thalassaemia major.

RESULTS

Despite regular transfusion and chelation therapy, 75% of the girls and 62% of the boys over the age of 12 years were below the third percentile for height. Hypogonadotropic hypogonadism was found in a similar percentage of patients. Moderate to marked zinc deficiency secondary to chelation therapy was considered unlikely because normal serum zinc levels were found in all but three of our patients, but we could not exclude the possibility of a marginal status of zinc nutrition causing growth failure. Growth hormone deficiency and diabetes mellitus were sometimes encountered but hypothyroidism, hypoparathyroidism and adrenal insufficiency were rare among our patients. Most of the patients with growth failure had normal growth hormone (GH) response to insulin induced hypoglycaemia. The serum insulin-like growth factor-1 (IGF-1) levels were low in our patients and no significant difference in the serum IGF-1 levels was found between prepubertal children with or without growth failure (0.4 +/- 0.1 mU/mL vs 0.37 +/- 0.11 mU/mL, P = 0.39). Similarly, no difference in the serum IGF-1 levels was found between pubertal children with or without growth failure (0.48 +/- 0.2 U/mL vs 0.56 +/- 0.14 U/mL, P = 0.26).

CONCLUSIONS

Delayed sexual maturation and a possible defect in growth unrelated to the GH-IGF-1 axis may be responsible for the growth failure in adolescent children with thalassaemia major.

A randomized controlled study evaluating the safety and efficacy of deferiprone treatment in thalassemia major patients from Hong Kong

A controlled, open-label and randomized study was conducted to evaluate the safety and efficacy of the oral iron chelator deferiprone (L1) in thalassemia major patients from Hong Kong. Forty-nine patients were recruited in total (median age: 20 years; range: 8 to 40 years). The division of the patients was determined based on liver iron content and put into either the poorly-chelated (Group I) or well-chelated (Group II) groups. In Group I, 20 patients received combined therapy of L1 daily plus desferrioxamine (DFO), in a reduced frequency of twice weekly, while the control group consisted of 16 patients who were treated with DFO alone. In Group II, six patients received L1 only, while the control group consisted of seven patients treated with DFO alone. Only patients who participated for longer than 6 months were analyzed for efficacy (n = 44). The median study period was 18 months. Transient and mild gastrointestinal upset (31%), joint pain (15%) and liver enzyme elevation (23%) were the most common side effects noted for L1. No case of neutropenia was observed in this study. Serum ferritin (SF) levels showed significant decline in the poorly-chelated patients using combined therapy (L1 and reduced frequency DFO) as compared to those on DFO alone. However, their pre- and post-study liver iron content was not significantly different. Evaluation of the well-chelated group demonstrated no significant change in SF or liver iron content in both the study and control arms. We conclude that the short-term use of L1, with or without DFO, was safe and efficacious in our Chinese patient cohort. The long-term efficacy of reducing iron overload by treatment regimens including L1 requires further study.

Family History of Early Infant Death Correlates with Earlier Age at Diagnosis But Not Shorter Time to Diagnosis for Severe Combined Immunodeficiency

BACKGROUND

Severe combined immunodeficiency (SCID) is fatal unless treated with hematopoietic stem cell transplant. Delay in diagnosis is common without newborn screening. Family history of infant death due to infection or known SCID (FH) has been associated with earlier diagnosis.

OBJECTIVE

The aim of this study was to identify the clinical features that affect age at diagnosis (AD) and time to the diagnosis of SCID.

METHODS

From 2005 to 2016, 147 SCID patients were referred to the Asian Primary Immunodeficiency Network. Patients with genetic diagnosis, age at presentation (AP), and AD were selected for study.

RESULTS

A total of 88 different SCID gene mutations were identified in 94 patients, including 49 IL2RG mutations, 12 RAG1 mutations, 8 RAG2 mutations, 7 JAK3 mutations, 4 DCLRE1C mutations, 4 IL7R mutations, 2 RFXANK mutations, and 2 ADA mutations. A total of 29 mutations were previously unreported. Eighty-three of the 94 patients fulfilled the selection criteria. Their median AD was 4 months, and the time to diagnosis was 2 months. The commonest SCID was X-linked (n = 57). A total of 29 patients had a positive FH. Candidiasis (n = 27) and bacillus Calmette-Guérin (BCG) vaccine infection (n = 19) were the commonest infections. The median age for candidiasis and BCG infection documented were 3 months and 4 months, respectively. The median absolute lymphocyte count (ALC) was 1.05 × 10⁹/L with over 88% patients below 3 × 10⁹/L. Positive FH was associated with earlier AP by 1 month (p = 0.002) and diagnosis by 2 months (p = 0.008), but not shorter time to diagnosis (p = 0.494). Candidiasis was associated with later AD by 2 months (p = 0.008) and longer time to diagnosis by 0.55 months (p = 0.003). BCG infections were not associated with age or time to diagnosis.

CONCLUSION

FH was useful to aid earlier diagnosis but was overlooked by clinicians and not by parents. Similarly, typical clinical features of SCID were not recognized by clinicians to shorten the time to diagnosis. We suggest that lymphocyte subset should be performed for any infant with one or more of the following four clinical features: FH, candidiasis, BCG infections, and ALC below 3 × 10⁹/L.

Plesiomonas shigelloides septicemia: case report and literature review

A 13-year-old girl with Plesiomonas shigelloides septicemia is reported. The infection occurred while she was receiving an allogeneic bone marrow transplantation for acute promyelocytic leukemia. Treatment with ciprofloxacin was successful. Twenty-one cases of Plesiomonas septicemia have been reported in the literature. Immunocompromised hosts, especially neonates, are commonly affected. The case mortality rate is high, with 13 of the reported patients dying of the infection. Successful treatment relies on the early identification of the organism and implementation of effective antibiotics.

Growth hormone treatment of short Chinese children with beta-thalassaemia major without GH deficiency

OBJECTIVE

Despite regular transfusion and desferrioxamine treatment, growth failure is commonly seen in adolescent children with beta-thalassaemia major. The growth failure has been thought to be due to GH resistance rather than GH deficiency. We investigated the effect of GH on short non-GH deficient children with beta-thalassaemia.

DESIGN

Recombinant human GH was given in a dose of 0.14 IU/kg/day subcutaneously in an open study.

PATIENTS

Fifteen prepubertal Chinese children with beta-thalassaemia major (ranging from 7.16 to 14.7 years in age) with height -1.5 SD or more below the population mean for age and a growth velocity of less than 5 cm/year were treated with growth hormone for one year. All children had peak GH response > 15mlU/l to insulin induced hypoglycaemia and normal thyroid function and adrenal reserve.

MEASUREMENTS

Anthropometric measurements were performed every 3 months. Morning urine was tested twice weekly for glycosuria. Blood count, renal and liver function tests, fasting blood glucose, IGF-I and fructosamine levels were assessed at entry and every 3 months during treatment. Fasting insulin was measured before and after 3 and 12 months of GH treatment. Skeletal maturity was assessed before and after one year of treatment.

RESULTS

Treatment was stopped in two children after 6 months because of poor growth response and noncompliance with treatment and in one child at 9 months because of bone marrow transplantation. In the 13 children, the growth velocity increased from 3.6 +/- 0.7 cm/year to 8 +/- 1.2 cm/year after one year of GH treatment (P < 0.001). IGF-I was low before treatment (10.1 +/- 2.7 nmol/l), rising significantly to 15.8 +/- 4.8, 18.4 +/- 4.6, 19.3 +/- 6.4 and 21.9 +/- 7.5 nmol/l at 3, 6, 9 and 12 months of treatment (P < 0.005). The mean pretreatment bone age in the 13 children was 9.58 +/- 1.41 years and increased to 10.53 +/- 1.43 years after one year of treatment (delta BA/CA 0.95 +/- 0.3 years). None of the patients developed glycosuria or hypertension. There was no significant change in blood count, renal and liver function, thyroid function, fasting blood glucose or insulin concentrations during treatment.

CONCLUSION

Growth failure in these children with normal GH reserve and low serum IGF-I concentrations would suggest GH insensitivity. Supraphysiological doses of exogenous GH can cause a significant increase in serum IGF-I levels and a significant improvement in short-term growth of short children with beta-thalassaemia major.

Paradoxical response of a pineal immature teratoma to combination chemotherapy

A case of primary intracranial germ cell tumour is reported in a 5-year-old Chinese boy who presented with symptoms and signs of increased intracranial pressure. Computed tomography (CT) scan of the brain revealed a multicystic tumour over the pineal region. Stereotactic biopsy yielded enteric epithelium and isolated cells with hyperchromatic nuclei and high nuclear-to-cytoplasmic ratio, suggesting the diagnosis of an immature teratoma. Grossly elevated serum and cerebrospinal fluid (CSF) levels of alpha-fetoprotein and mildly elevated levels of beta human chorionic gonadotrophin suggested the simultaneous presence of embryonal tissues. Combination chemotherapy with cisplatin, etoposide, and bleomycin resulted in a gradual but complete normalisation of the serum and CSF tumour markers. Paradoxically, the patient's consciousness deteriorated and repeat CT scan after 3 months of treatment showed that the tumour was actually increasing in size. Complete surgical removal was attempted and histologic sections of the specimen revealed only mature teratomatous tissues. The child is now well and remains disease-free with minimal left hemiparesis 12 months after completion of treatment. This case illustrates the importance of combined neoadjuvant chemotherapy and surgery in the management of intracranial non-germinomatous germ cell tumour harbouring both germ cell and teratomatous components, while monitoring of both biochemical and radiological parameters are necessary in assessing the clinical behaviour of mixed germ cell tumours.

Minimal residual disease-based risk stratification in Chinese childhood acute lymphoblastic leukemia by flow cytometry and plasma DNA quantitative polymerase chain reaction

Minimal residual disease, or MRD, is an important prognostic indicator in childhood acute lymphoblastic leukemia. In ALL-IC-BFM 2002 study, we employed a standardized method of flow cytometry MRD monitoring for multiple centers internationally using uniformed gating, and determined the relevant MRD-based risk stratification strategies in our local patient cohort. We also evaluated a novel method of PCR MRD quantitation using peripheral blood plasma. For the bone marrow flow MRD study, patients could be stratified into 3 risk groups according to MRD level using a single time-point at day-15 (Model I) (I-A: <0.1%, I-B: 0.1-10%, I-C: >10%), or using two time-points at day-15 and day-33 (Model II) (II-A: day-15<10% and day-33<0.01%, II-B: day-15 ≥ 10% or day-33 ≥ 0.01% but not both, II-C: day-15 ≥ 10% and day-33 ≥ 0.01%), which showed significantly superior prediction of relapse (p = .00047 and <0.0001 respectively). Importantly, patients with good outcome (frequency: 56.0%, event-free survival: 90.1%) could be more accurately predicted by Model II. In peripheral blood plasma PCR MRD investigation, patients with day-15-MRD ≥ 10(-4) were at a significantly higher risk of relapse (p = 0.0117). By multivariate analysis, MRD results from both methods could independently predict patients' prognosis, with 20-35-fold increase in risk of relapse for flow MRD I-C and II-C respectively, and 5.8-fold for patients having plasma MRD of ≥ 10(-4). We confirmed that MRD detection by flow cytometry is useful for prognostic evaluation in our Chinese cohort of childhood ALL after treatment. Moreover, peripheral blood plasma DNA MRD can be an alternative where bone marrow specimen is unavailable and as a less invasive method, which allows close monitoring.

Mechanical thrombectomy in inferior vena cava thrombosis after caval filter placement: a report of three cases

Inferior vena caval (IVC) filter thrombosis in patients with contraindications to anticoagulant therapy is a difficult and challenging clinical problem. We report our experience in treating three such patients using a mechanical thrombectomy device, which resulted in rapid symptomatic relief until anticoagulant therapy could be safely introduced.

Hypertransfusion for spinal cord compression secondary to extramedullary hematopoiesis

A 19-year-old girl with thalassemia intermedia presented with signs of thoracic spinal cord compression secondary to extramedullary hematopoiesis. She was started on a transfusion regimen to maintain a hemoglobin level of more than 12.5 g/dL. Clinical signs disappeared within the first week and circulating erythroblastemia was completely suppressed by the second week. Magnetic resonance imaging 4 weeks after diagnosis revealed near-complete resolution of the extradural mass, followed by gradual improvement in the posterior tibial somatosensory evoked potentials. Transfusion therapy may be diagnostically and therapeutically useful in spinal cord compression secondary to extramedullary hematopoiesis, obviating the need for surgery or radiotherapy.

Paraneoplastic limbic encephalitis masquerading as chronic behavioural disturbance in an adolescent girl

AIM

To describe an unusual but treatable cause of behavioural disturbance in adolescence.

METHODS

The case is reported of a 15-y-old girl presenting with acute confusion, memory problems and psychotic symptoms following an 18-mo history of change in personality, school failure and running away from home. A review of the literature is also presented.

RESULTS

Microbiology, toxicology, computed tomography and magnetic resonance imaging did not show any pathology of the central nervous system. Bilateral ovarian immature teratomas were eventually diagnosed and removed. The rapid improvement in the patient's mental and cognitive functions after corticosteroid treatment and the abnormality shown on the single photon emission computed tomography suggested a diagnosis of paraneoplastic limbic encephalitis.

CONCLUSION

Paediatricians and neurologists should be aware of this rare disease entity among the more common conditions of behavioural problems and substance abuse in adolescents.

Intraspinal and intracranial hemorrhage after lumbar puncture

Two cases of spinal epidural hematoma and two cases of intracranial subdural hematoma after lumbar puncture (LP) are reported in children receiving chemotherapy for acute lymphoblastic leukemia and non-Hodgkin lymphoma. The bleeding was asymptomatic but interfered with treatment in one case, and caused either severe backache or headache but no neurological deficit in the other three patients. The platelet counts were 8 and 46 x 10(9)/L in two patients and were normal in the other patients at the time of LP. All recovered without surgical treatment. There is an inherent, albeit uncommon, risk of bleeding into the central nervous system associated with LP in children with cancer and should be distinguished from postdural puncture headache (PDPH). Thrombocytopenia is not always an accompanying factor.

A novel beta-delta globin gene fusion, anti-Lepore Hong Kong, leads to overexpression of delta globin chain and a mild thalassaemia intermedia phenotype when co-inherited with beta(0)-thalassaemia

Anti-Lepore haemoglobins (Hb) are rare betadelta fusion variants that arise from non-homologous crossover during meiosis, resulting in a delta-betadelta-beta configuration. A novel anti-Lepore mutation (anti-Lepore Hong Kong) was found in two Chinese families with raised Hb A(2). Direct sequencing revealed a crossover within a 54-bp region spanning the junction of cap site (CAP) and exon 1, which predicted the production of normal delta-globin. Determination of alpha/beta-mRNA ratios by quantitative real-time polymerase chain reaction demonstrated downregulation of the beta gene in cis due to the interposed betadelta fusion gene. Although heterozygotes have normal red cell indices and are clinically silent, compound heterozygotes with beta(0) mutation in trans produce a mild thalassaemia intermedia phenotype with a markedly raised Hb A(2) level that may mimic clinically mild Hb E-beta(+)-thalassaemia. Awareness of the presence of anti-Lepore Hong Kong will help to resolve diagnostic problems in regions with significant prevalence of globin disorders.

Neurophysiologic study of beta-thalassemia patients

Neurophysiologic investigations were performed in 34 Chinese patients with beta-thalassemia major maintained on long-term desferrioxamine treatment to look for subclinical toxicity in the auditory, visual, peripheral, or central neural pathways. In the auditory pathway study, four patients (12%) had mild sensorineural hearing impairment. Two patients (6%) had increased P 100 latencies in the visual evoked potential study, and nine patients (26%) had abnormal electroretinogram results. All had normal electrooculograms. Ophthalmoscopic examination was abnormal in three patients (9%), and three (9%) had a visual field defect. In the peripheral or central nervous pathways, seven patients (21%) had sensory neuropathy, of which three cases were probably related to diabetes mellitus. All had normal motor conduction velocities. Four patients (12%) had increased cortical latencies of median or posterior tibial somatosensory evoked potential. Abnormalities in multiple neural pathways were seen in four patients (12%). There was a significant association between subclinical toxicity to the peripheral or central nervous systems and serum ferritin level (P < .03) and the presence of diabetes mellitus (P < .002). There was no significant relationship between the age, dosage, or duration of desferrioxamine used and the increased risk of neurotoxicity to the auditory, visual, peripheral, or central nervous systems. There was also no association between the risk of neurotoxicity and the serum zinc, copper, or fructosamine levels.

Septic arthritis in hemophilia with central venous catheter: a case report

A case is reported of septic arthritis in a child with human immunodeficiency virus-negative hemophilia A associated with a Staphylococcus aureus catheter-associated septicemia. The infection occurred in relation to the use of a totally implantable central venous catheter. The organism was eventually eradicated with antibiotics injected via the catheter. With increasing use of such catheters in the hemophilic population, clinicians should be alerted to the possibility of septic arthritis for prompt diagnosis and treatment.

Isolated thrombocytopenia in childhood: what if it is not immune thrombocytopenia?

INTRODUCTION

Childhood immune thrombocytopenia (ITP) remains a diagnosis of exclusion when isolated thrombocytopenia is not part of another disease process. In practice, the diagnosis of ITP can only be confirmed when thrombocytopenia resolves or is excluded after the recognition of a primary cause.

METHODS

The records of 87 consecutive children with isolated thrombocytopenia seen over a nine-year period in a private paediatric haematology practice were reviewed retrospectively. Children in whom a primary cause was eventually found were the subjects of a further descriptive study.

RESULTS

9 (10%) children with isolated thrombocytopenia were not diagnosed with ITP because a primary disease was found. Of these nine cases, four had thrombocytopenia recognised during the neonatal period, consisting of perinatal cytomegalovirus infection (n = 2), meconium aspiration pneumonia (n = 1) and transient abnormal myelopoiesis associated with Down syndrome (n = 1). The remaining five children were each found to have familial thrombocytopenia, portal hypertension, cutaneous mastocytosis, May-Hegglin anomaly and systemic lupus erythematosus. Two of them had a history of failure of response to corticosteroid therapy.

CONCLUSION

Secondary thrombocytopenia is not uncommon in a tertiary paediatric specialty practice with adequate evaluation. Thrombocytopenia occurring during the newborn period and failure of steroid therapy are predictive of secondary cases.