We screened 38 G6PD-deficient male Chinese neonates for known G6PD mutations using established PCR-based techniques. We found 50.0% (19 of 38) were mutation 1376G>T, 34.2% (13 of 38) were mutation 1388G>A, 5.2% (2 of 38 ) were mutation 95A>G and 2.2% (1 of 38) was mutation 1024C>T. In 7% (3 of 38) of the cases the mutations remained uncharacterised. Sixty three percent (24 of 38) of the G6PD deficient neonates had neonatal jaundice with 28.9 % (11 of 38) developing moderate to severe hyperbilirubinemia. The group of neonates with 1388 mutation showed the highest incidence of moderate to severe hyperbilirubinemia requiring phototherapy and/or exchange transfusion respectively. Majority (70%) of the G6PD deficient neonates showed severe enzyme deficiency. However, there was no meaningful association between the level of enzyme activity and the severity of neonatal jaundice. In summary, four mutations account for more than 90% of the G6PD deficiency cases among the Chinese in Malaysia and the pattern of distribution of the molecular variants is similar to those found among the Chinese in Taiwan and southern mainland China. Our findings also suggest the possible association of nt 1388 mutation with severe neonatal jaundice.
We performed DNA analysis using cord blood samples on 86 male Malay neonates diagnosed as G6PD deficiency in the National University of Malaysia Hospital by a combination of rapid PCR-based techniques, single-stranded conformation polymorphism analysis (SSCP) and DNA sequencing. We found 37.2% were 871G>A (G6PD Viangchan), 26.7% were nt 563 C>T (G6PD Mediterranean) and 15.1% were 487G>A (G6PD Mahidol) followed by 4.7% 1376G>T (G6PD Canton), 3.5% 383T>C (G6PD Vanua Lava), 3.5% 592C>T (G6PD Coimbra), 2.3% 1388G>A (G6PD Kaiping), 2.3% 1360C>T (G6PD Union), 2.3% 1003G>A (G6PD Chatham), 1.2% 131C>G (G6PD Orissa) and 1.2% 1361G>A (G6PD Andalus). Seventy-one (82.6%) of the 86 G6PD-deficient neonates had neonatal jaundice. Fifty seven (80%) of the 71 neonates with jaundice required phototherapy with only one neonate progressing to severe hyperbilirubinemia (serum bilirubin >340 micromol/l) requiring exchange transfusion. There was no significant difference in the incidence of neonatal jaundice, mean serum bilirubin level, mean age for peak serum bilirubin, percentage of babies requiring phototherapy and mean number of days of phototherapy between the three common variants. In conclusion, the molecular defects of Malay G6PD deficiency is heterogeneous and G6PD Viangchan, Mahidol and Mediterranean account for at least 80% of the cases. Our findings support the observation that G6PD Viangchan and Mahidol are common Southeast Asian variants. Their presence in the Malays suggests a common ancestral origin with the Cambodians, Laotians and Thais. Our findings together with other preliminary data on the presence of the Mediterranean variant in this region provide evidence of strong Arab influence in the Malay Archipelago.
Neonatal screening for G6PD deficiency has long been established in many countries. The aim of the study was to determine whether the routine semiquantitative fluorescent spot test could detect all cases of G6PD deficiency, including those cases with partial deficiency (residual red cell G6PD activity between 20-60% of normal). We compared the results of G6PD screening by the semiquantitative fluorescent spot test and quantitative G6PD activity assay on a group of 976 neonates and 67 known female heterozygotes. The values for mean G6PD activity of G6PD-normal neonates and 293 healthy adult females were determined. There was no significant difference in the mean normal G6PD activity between the two racial groups in the neonates (669 Malays, 307 Chinese) and in the 293 healthy adult females (150 Malays, 143 Chinese) group. The values for the upper limits of total deficiency (20% of normal residual activity) for neonates and adult females were 2.92 U/gHb and 1.54 U/gHb, respectively. The upper limits of partial deficiency (60% of normal residual activity) were 8.7 U/gHb and 4.6 U/gHb respectively. The prevalence of G6PD deficiency among the male neonates was 5.1% (26) by both the fluorescent spot test and the enzyme assay method. The G6PD activity levels of all 26 cases of G6PD-deficient male neonates were < 20% normal (severe enzyme deficiency). In the female neonate group, the frequency of G6PD deficiency was 1.3% (6 of 472) by the fluorescent spot test and 9.35% (44 of 472) by enzyme assay. The 6 cases diagnosed as deficient by the fluorescent spot test showed severe enzyme deficiency (< 2.92 U/gHb). The remaining 38 female neonates had partial enzyme deficiency and all were misdiagnosed as normal by the fluorescent spot test. In the female heterozygote group, G6PD deficiency was diagnosed in 53% (35 of 67) by enzyme assay and in 7.5% (4 of 67) of cases by the fluorescent spot test. The 4 cases detected by fluorescent spot test had severe enzyme deficiency (<1.6 U/gHb). The remaining 31 (46.3%) cases, diagnosed as normal by fluorescent spot test, showed partial G6PD deficiency. In conclusion, we found that the semiquantitative fluorescent spot test could only diagnose cases of total G6PD deficiency and misclassified the partially-deficient cases as normal. In this study, the overall prevalence of G6PD deficiency was 3.28% by the semiquantitative fluorescent spot test and 7.17% by enzyme assay. This means that 3.9% of G6PD-deficient neonates were missed by the routine fluorescent spot test and they were found to be exclusively females. This study demonstrates a need to use a method that can correctly classify female heterozygotes with partial G6PD deficiency. The clinical implication is that these individuals may be at risk of the hemolytic complication of G6PD deficiency.
G6PD deficiency is the most common human enzymopathy and affects 200 million people worldwide. To date more than 400 biochemical variants and at least 60 different point mutations in the G6PD locus have been discovered. In Malaysia the overall incidence of G6PD deficiency among males is 3.1%, being more prevalent among the Chinese and Malays and less common among the Indians. As part of our initial effort to characterise G6PD deficiency in the Malaysian population, we investigated 18 G6PD deficient Chinese male neonates for the G6PD mutation G-->T at nt 1376, a common mutation seen among the Chinese in Taiwan and mainland China. The mutation was detected by a PCR-based technique using primers that artificially create a site for restriction enzyme Xho I. We found 61% (11 out of 18) of the Chinese G6PD deficient male neonates positive for this mutation. Study of enzyme electrophoretic mobility in 7 of the cases positive for this mutation revealed three different patterns of mobility. 107% (5 out of 7), 103% (1 out of 7) and 100% (1 out of 7). This study shows that mutation G-->T at nt 1376 is a common allele causing G6PD deficiency in Malaysians of Chinese origin. The finding of different patterns of electrophoretic mobility among the 7 cases positive for 1376 G-->T mutation supports the notion that diverse biochemical variants may share the same mutation.
Anaemia is a global health problem including Malaysia. In adults, anaemia may affect work productivity. Iron deficiency anaemia and thalassaemia are common causes of anaemia in Malaysia. However, there is scarcity of data on national prevalence of iron deficiency anaemia and thalassaemia, especially in young adults. This cross sectional study was performed to determine the prevalence of iron deficiency anaemia and thalassaemia among medical students of Universiti Kebangsaan Malaysia Medical Centre (UKMMC).
Juvenile myelomonocytic leukaemia (JMML), previously known as juvenile chronic myeloid leukaemia (JCML) is a rare, myelodysplastic - myeloproliferative disease typically presenting in early childhood. This disorder is difficult to distinguish from other myeloproliferative syndrome such as chronic myeloid leukaemia (CML) because of the similarities in their clinical and bone marrow findings. However, because of its unique biological characteristics such as absolute monocytosis with dysplasia, absence of Philadelphia chromosome or BCR-ABL fusion protein, hypergammaglobulinaemia and raised fetal haemoglobin level, this disorder does not satisfy the criteria for inclusion in the CML or chronic myelomonocytic leukaemia (CMML) group, as seen in adult patients. We describe a series of three patients with JMML, who had almost similar clinical and laboratory findings, and discuss the difficulty in the classification and treatment of the disease.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the commonest causes of neonatal jaundice in Malaysia. Screening of cord blood for G6PD deficiency by the semiquantitative fluorescent spot test (FST) is performed in Malaysia but this test can miss cases of partial G6PD deficiency. The OSMMR-D kit assay measures G6PD activity and hemoglobin (Hb) concentration, allowing direct expression of results in U/gHb. We evaluated this method and established the normal range for G6PD activity in normal term neonates and adults. EDTA blood from 94 neonates and 295 adults (age 15-59 years old) with normal Hb and FST were selected. The normal means for G6PD activity for neonates and adults were 12.43 +/- 2.28 U/gHb and 9.21 +/- 2.6 U/gHb, respectively; the reference ranges for normal G6PD activity in neonates and adults were 10.15-14.71 U/gHb and 6.61-11.81 U/gHb respectively. There were no significant differences in mean normal G6PD activity between the Malays and Chinese racial groups or between genders. The upper and lower limit cut-off points for partial deficiency in neonates were 7.4 U/gHb (60% of the normal mean) and 2.5 U/gHb (20% of the normal mean), respectively. For adults, the upper and lower limit cut-off points for partial deficiency in adults were 5.52 U/gHb (60% of the normal mean) and 1.84 U/gHb (20% of the normal mean), respectively. The quantitation of G6PD enzymes using this OSMMR-D kit with Hb normalization was simple since the Hb was analyzed simultaneously and the results were reproducible with a CV of less than 5%.
Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haemopoietic stem cell disorder arising from somatic mutation of the X-linked PIG-A gene which leads to deficiency of the glycosylphosphatidylinositol (GP1) membrane anchor proteins such as CD 59 (MIRL: membrane inhibitor of reactive lysis) and CD 55 (DAF: decay accelerating factor). Allogeneic peripheral blood stem cell transplant (PBSCT) is a curative mode of treatment in symptomatic PNH patients. Assessment of donor chimerism for PBSCT can be performed by various methods including short tandem repeat loci (STR) and variable number of tandem repeats (VNTR). Flow cytometry, which is much cheaper and faster, also can be used to assess engraftment in patients with PNH. Engrafted patients will show the presence of CD 55 and CD 59 on their red cells and white cells. We describe here the usefulness of flow cytometry in the assessment of donor chimerism following allogeneic PBSCT, in a case of PNH.
A study was conducted to describe the prevalence and distribution of zoonotic Brucella melitensis in goats in Peninsular Malaysia. Using serosurveillance data of the last decade (2000-2009) involving 119,799 goats and 3555 farms, the seroprevalence of brucellosis among goats was 0.91% (95% CI=0.86-0.96) and among farms was 7.09% (95% CI=6.27-7.98). The odds of brucellosis was significantly (P<0.05) higher in the later part of the decade, in larger herd size and among the states located in the peninsula as compared to eastern Malaysia. The infection was detected throughout Malaysia but at generally low seroprevalences with states like Perlis that border neighbouring countries having higher seroprevalence of brucellosis than other non-border states.
Caprine brucellosis is a bacterial zoonotic infection affecting goats especially in developing countries all over the world. In Malaysia, the risk factors associated with this infection in farms have not been studied. A case-control study was carried out in goat farms in four states of Malaysia to elucidate the risk factors associated with the infection on the farms using structured questionnaires and face-to-face interviews. Results indicate that the introduction of new animals (OR = 5.25; 90 % CI = 1.46, 18.88), younger age category of farms (OR = 5.53; 90 % CI = 1.09, 21.66), and farms with single breed of goats (OR = 8.50; 90 % CI = 1.27, 41.97) were significant risk factors for brucellosis. In order to control brucellosis or possibly eradicate it in goat farms, these factors need to be dealt with. Enforcing stringent importation protocols or complete ban of goat importation from brucellosis endemic countries will help reduce risk of introducing new infection into the country.
Immunophenotyping of acute leukaemias has become an important diagnostic tool in haematology laboratories as it is now well recognised that the presence of certain surface markers has prognostic significance. In 1988, we experimented with the alkaline phosphatase anti-alkaline phosphatase (APAAP) method for immunophenotyping of leukaemic cells in our laboratory. 48 cases of peroxidase-negative acute leukaemias were studied. Our study showed that 2 peroxidase-negative cases carried myeloid surface markers, 44% were negative for the markers studied and 5% were unclassified due to technical problems. We concluded that the APAAP method is a useful technique for demonstrating cell markers in leukaemic cells as the reaction is reddish and usually intense. We failed to demonstrate surface markers in 44% of the cases probably because of the choice of a limited panel of monoclonal antibodies.
A previously healthy eleven month old male Malay infant presented with fever, upper respiratory tract infection and right knee swelling. Pallor, bilateral proptosis, hepatosplenomegaly, multiple scalp swellings and a right cheek swelling were observed. Investigations revealed that he had acute monoblastic leukemia or FAB M5a. Immunophenotyping by flow cytometry showed that the blast cells were positive for CD45, CD13, CD33, HLA-DR, CDllc, CD71, EMA, and Cytokeratin. They were negative for CD34, CD19, CD10, CD22, CD2, CD3, CD4, CD7, CD8, CD61, NK, Glycophorin A, and CD14. The monoblasts were used to evaluate anti-EMA and anti-cytokeratin. They were unexpectedly found to be positive. Acute monoblastic leukaemias are well known to show extramedullary infiltration and this may be their primary mode of presentation. Thus, in immunochemostry, when using EMA and cytokeratin expression in the differential diagnosis of neoplastic diseases, it is important to consider that monoblasts may express these markers as illustrated by this case.
Multidrug resistance (MDR) is believed to be responsible for poor response of patients towards chemotherapy particularly patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). The best-characterized resistance mechanism is the one mediated by permeability-glycoprotein (P-gp) encoded by MDR1 gene, which is responsible for drug efflux. We studied P-gp and multidrug resistance-associated protein 1 (MRP1) expression and functional activities in 43 newly diagnosed acute leukemia cases (19 paediatric ALL cases and 24 adult AML cases). The expression and functional activities were examined using flow cytometry and MultiDrugQuant assay kit (involving calcein AM uptake and efflux). P-gp and MRP1 expression and its functional activities were observed in 68.4% of paediatric ALL. In adult AML cases, all cases expressed MRP1 and its functional activities but only 58.3% were positive for P-gp and its functional activities. We were able to show a significant correlation between the expression of the multidrug resistant protein (P-gp and MRP1) and their functional activity in adult AML and paediatric ALL samples.
The expression of the multidrug resistance (MDR) proteins may influence the outcome of treatment in patients with acute leukemia. The aim of this study was to determine the IC50 of cytotoxic drugs (cytosine arabinoside, ara-C and daunorubicin, dnr) using the in vitro 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)2H-tetrazolium, inner salt (MTS) assay method. A total of 82 newly diagnosed acute leukemia cases (43 adult myeloid leukaemia, AML cases and 39 acute lymphoblastic leukaemia, ALL cases) and 16 relapsed cases (8 AML cases and 8 ALL cases) were studied. The MTS assay was performed using two cytotoxic drugs, dnr and ara-C. Cells were incubated with different concentrations of drugs for 4 days and the IC50 was extrapolated from the viability curve. In newly diagnosed cases, we found that childhood ALL samples showed higher IC50 values of dnr (0.040 +/- 2.320) compared to adult AML samples (0.021 +/- 0.158). In contrast, newly diagnosed adult AML samples showed higher IC50 values of ara-C (0.157 +/- 0.529) compared to childhood ALL samples (0.100 +/- 2.350). In relapsed cases, two samples of childhood ALL showed IC50 values of dnr (0.910 +/- 1.760) and ara-C (1.310 +/- 2.390), which was higher compared to childhood AML samples (0.129 +/- 0.214 and 0.210 +/- 0.003, respectively). However, there was no correlation between IC50 values of these drugs tested with clinical outcome. In conclusion, we found that MTS assay is an easy, rapid and non laborious method to study in vitro drug resistance in acute leukaemia cases.
Prenatal diagnosis is essential in the new era of diagnosis and management of genetic diseases in obstetrics. Multiple ligation-dependent probe amplification (MLPA) is a recent technique for prenatal diagnosis for the relative quantification of 40 different nucleic acid sequences in one single reaction. We had utilized the MLPA technique in detecting aneuploidies in amniotic fluid samples from 25 pregnant women from the Obstetrics and Gynaecology Department UKMMC, versus the quantitative fluorescent polymerase chain reaction (QF-PCR) method. Conclusive results were obtained in 18 cases and all were concordant with that of the QF-PCR. All four cases of trisomies were correctly identified including one case with maternal cell contamination.
Primary nasal lymphomas are rare. One of the most common cellular subtypes in the Asian population is natural killer (NK)/T-cell lymphoma (NKTL) with a high association of EBV. We report a case of a 42-year-old female, who presented with a worsening sore throat, odynophagia, dysphagia to solid food due to oropharyngeal ulcers and bilateral nasal blockage and recurrent fever for the past two weeks prior to admission. Physical examination revealed ulcers over the soft palate with nasopharyngeal slough. Computerized Tomography (CT) scan of the neck showed nasopharyngeal abscess with bilateral maxillary ethnoidal sinusitis. The diagnostic and management challenge is discussed.
Chronic myeloproliferative diseases (MPDs) are heterogenous group of haematological malignant disorders. It is now a well recognized fact that the JAK2 (V617F) mutation occurs in majority of the patients with polycythaemia vera (PV) and half of those with myelofibrosis and essential thrombocythaemia. The presence of JAK2 (V617F) mutation is considered an important criterion for the exclusion of secondary-reactive from clonal disorders. In the present uni-institutional study, we analyzed the JAK2 (V617F) mutation status in the ethnic Malay and Chinese patients who were diagnosed as MPDs.
Non-secretory multiple myeloma (NSMM) is a rare variant of the classic form of multiple myeloma (MM). In NSMM, no monoclonal gammopathy can be detected in serum or urine by conventional techniques, making the diagnosis more difficult. We describe a 71-year-old man who had been diagnosed and treated for granulocytic sarcoma one year prior to his recent problems of progressive low-back pain of two months duration. Skeletal X-rays showed diffuse osteolytic lesions with multiple pathological fractures but there was no monoclonal gammopathy in the serum or urine. The biopsy of the lytic lesion on the upper part of the femur showed infiltration by abnormal plasma cells. A diagnosis of NSMM was made and he was treated with chemotherapy. The early diagnostic difficulty and the challenges faced regarding the case are discussed.
A 35-year-old man from Bangladesh, who had been in Malaysia for approximately a year, was extensively investigated for more than two months in a state hospital for pyrexia with hepatosplenomegaly. However, no obvious cause of his illness was found. He was treated with multiple antibiotics with no resolution of pyrexia and hepatosplenomegaly. He was later referred to the Haematology Unit, Universiti Kebangsaan Malaysia for further assessment as a case of lymphoma. On carefully reviewing his bone marrow aspirate smears, the diagnosis of leishmaniasis (kala-azar) was finally made. The patient responded to treatment with pentamidine.
Myeloperoxidase (MPO) is present in azurophilic granules which appear in the promyelocyte stage of differentiation and is expressed in granulomonocytic cells. MPO is usually detected by cytochemistry. The demonstration of peroxidase in at least 3% of bone marrow blasts defines an acute leukaemia as acute myeloblastic leukaemia (AML). MPO is important in distinguishing acute myeloblastic leukaemia (AML) from acute lymphoblastic leukaemia (ALL). It is difficult to diagnose AML with minimal evidence of myeloid differentiation (AML- M0) by conventional light microscopy. However, these AML-M0 blasts can be detected by monoclonal antibodies. Anti-MPO recognizes the enzymatically inactive precursor forms of MPO. There are a few commercially available monoclonal antibodies against MPO. In this study, we evaluated two monoclonal antibodies against MPO from different commercial sources.