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Miltefosine suppression of Pten null T-ALL leukemia via β-catenin degradation through inhibition of pT308-Akt and TGFβ1/Smad3

Zhang Y, Lee S, Xu W

Biochem Biophys Res Commun, 2020 04 16;524(4):1018-1024.
PMID: 32063363 DOI: 10.1016/j.bbrc.2020.02.021

Pten deletion in the hematopoietic stem cells (HSC) causes a myeloproliferative disorder, which may subsequently develop into a T-cell acute lymphoblastic leukemia (T-ALL). β-catenin expression was dramatically increased in the c-KitmidCD3+Lin- leukemia stem cells (LSC) and was critical for T-ALL development. Therefore, the inactivation of β-catenin in LSC may have a potential to eliminate the LSC. In this study, we investigated the mechanism of enhancement of the β-catenin expression and subsequently used a drug to inactivate β-catenin expression in T-ALL. Western blot (WB) analysis revealed an increased level of β-catenin in the leukemic cells, but not in the pre-leukemic cells. Furthermore, the WB analysis of the thymic cells from different stages of leukemia development showed that increased expression of β-catenin was not via the pS9-GSK3β signaling, but was dependent on the pT308-Akt activation. Miltefosine (Hexadecylphosphocholine) is the first oral anti-Leishmania drug, which is a phospholipid agent and has been shown to inhibit the PI3K/Akt activity. Treatment of the PtenΔ/Δ leukemic mice with Miltefosine for different durations demonstrated that the pT308-Akt and the β-catenin expressions were inhibited in the leukemia blast cells. Miltefosine treatment also suppressed the TGFβ1/Smad3 signaling pathway. Analysis of TGFβ1 in the sorted subpopulations of the blast cells showed that TGFβ1 was secreted by the CD3+CD4- subpopulation and may exert effects on the subpopulations of both CD3+CD4+ and CD3+CD4- leukemia blast cells. When a TGFβR1 inhibitor, SB431542 was injected into the PtenΔ/Δ leukemic mice, the Smad3 and β-catenin expressions were down-regulated. On the basis of the results, we conclude that Miltefosine can suppress leukemia by degrading β-catenin through repression of the pT308-Akt and TGFβ1/Smad3 signaling pathways. This study demonstrates a possibility to inhibit Pten loss-associated leukemia genesis via targeting Akt and Smad3.

Matched MeSH terms: Gene Deletion
Fulltext ASPP2 deficiency causes features of 1q41q42 microdeletion syndrome

Zak J, Vives V, Szumska D, Vernet A, Schneider JE, Miller P, et al.

Cell Death Differ, 2016 Dec;23(12):1973-1984.
PMID: 27447114 DOI: 10.1038/cdd.2016.76

Chromosomal abnormalities are implicated in a substantial number of human developmental syndromes, but for many such disorders little is known about the causative genes. The recently described 1q41q42 microdeletion syndrome is characterized by characteristic dysmorphic features, intellectual disability and brain morphological abnormalities, but the precise genetic basis for these abnormalities remains unknown. Here, our detailed analysis of the genetic abnormalities of 1q41q42 microdeletion cases identified TP53BP2, which encodes apoptosis-stimulating protein of p53 2 (ASPP2), as a candidate gene for brain abnormalities. Consistent with this, Trp53bp2-deficient mice show dilation of lateral ventricles resembling the phenotype of 1q41q42 microdeletion patients. Trp53bp2 deficiency causes 100% neonatal lethality in the C57BL/6 background associated with a high incidence of neural tube defects and a range of developmental abnormalities such as congenital heart defects, coloboma, microphthalmia, urogenital and craniofacial abnormalities. Interestingly, abnormalities show a high degree of overlap with 1q41q42 microdeletion-associated abnormalities. These findings identify TP53BP2 as a strong candidate causative gene for central nervous system (CNS) defects in 1q41q42 microdeletion syndrome, and open new avenues for investigation of the mechanisms underlying CNS abnormalities.

Matched MeSH terms: Gene Deletion
High prevalence of Southeast Asian ovalocytosis in Malays with distal renal tubular acidosis

Yusoff NM, Van Rostenberghe H, Shirakawa T, Nishiyama K, Amin N, Darus Z, et al.

J Hum Genet, 2003;48(12):650-653.
PMID: 14618420 DOI: 10.1007/s10038-003-0095-2

Southeast Asian ovalocytosis (SAO) is a red blood cell abnormality common in malaria-endemic regions and caused by a 27 nt deletion of the band 3 protein gene. Since band 3 protein, also known as anion exchanger 1, is expressed in renal distal tubules, the incidence of SAO was examined in distal renal tubular acidosis (dRTA) in Malays in Kelantan, Malaysia. Twenty-two patients with dRTA and 50 healthy volunteers were examined for complication of SAO by both morphological and genetic analyses. SAO was identified in 18 of the 22 dRTA patients (81.8%), but only two of the 50 controls (4%). The incidence of SAO was significantly high in those with dRTA (p<0.001), indicating a dysfunctional role for band 3 protein/anion exchanger 1 in the development of dRTA.

Matched MeSH terms: Gene Deletion
Construction and characterization of a Burkholderia pseudomallei wzm deletion mutant

Yuen CW, Ong EB, Mohamad S, Manaf UA, Najimudin N

J Microbiol Biotechnol, 2012 Oct;22(10):1336-42.
PMID: 23075783

In Burkholderia pseudomallei, the pathogen that causes melioidosis, the gene cluster encoding the capsular polysaccharide, is located on chromosome 1. Among the 19 capsular genes in this cluster, wzm has not been thoroughly studied. To study the function of wzm, we generated a deletion mutant and compared it with the wild-type strain. The mutant produced less biofilm in minimal media and was more sensitive to desiccation and oxidative stress compared with the wild-type strain, indicating that wzm is involved in biofilm formation and membrane integrity. Scanning electron microscopy showed that the bacterial cells of the mutant strain have more defined surfaces with indentations, whereas cells of the wild-type strain do not.

Matched MeSH terms: Gene Deletion*
Cgl-SLT2 is required for appressorium formation, sporulation and pathogenicity in Colletotrichum gloeosporioides

Yong HY, Bakar FD, Illias RM, Mahadi NM, Murad AM

Braz J Microbiol, 2013 Dec;44(4):1241-50.
PMID: 24688518

The mitogen-activated protein (MAP) kinase pathways has been implicated in the pathogenicity of various pathogenic fungi and plays important roles in regulating pathogenicity-related morphogenesis. This work describes the isolation and characterization of MAP kinase gene, Cgl-SLT2, from Colletotrichum gloeosporioides. A DNA sequence, including 1,633 bp of Cgl-SLT2 open-reading frame and its promoter and terminator regions, was isolated via DNA walking and cloned. To analyze gene function, a gene disruption cassette containing hygromycin-resistant gene was constructed, and Cgl-SLT2 was inactivated via gene deletion. Analysis on Cgl-slt2 mutant revealed a defect in vegetative growth and sporulation as compared to the wild-type strain. When grown under nutrient-limiting conditions, hyperbranched hyphal morphology was observed in the mutant. Conidia induction for germination on rubber wax-coated hard surfaces revealed no differences in the percentage of conidial germination between the wild-type and Cgl-slt2 mutant. However, the percentage of appressorium formation in the mutant was greatly reduced. Bipolar germination in the mutant was higher than in the wild-type at 8-h post-induction. A pathogenicity assay revealed that the mutant was unable to infect either wounded or unwounded mangoes. These results suggest that the Cgl-SLT2 MAP kinase is required for C. gloeosporioides conidiation, polarized growth, appressorium formation and pathogenicity.

Matched MeSH terms: Gene Deletion
Intrabacterial proton-dependent CagA transport system in Helicobacter pylori

Wu H, Nakano T, Daikoku E, Morita C, Kohno T, Lian HH, et al.

J Med Microbiol, 2005 Dec;54(Pt 12):1117-1125.
PMID: 16278423 DOI: 10.1099/jmm.0.46158-0

Helicobacter pylori CagA modifies the signalling of host cells and causes gastric diseases. Although CagA is injected into gastric epithelial cells through the type IV secretion machinery, it remains unclear how CagA is transported towards the machinery in the bacterial cytoplasm. In this study, it was determined that the proton-dependent intracytoplasmic transport system correlates with the priming of CagA secretion from H. pylori. The cytotoxicity of neutral-pH- and acidic-pH-treated H. pylori was examined in the AGS cell line. The amount of phosphorylated CagA in AGS cells incubated with acidic-pH- and neutral-pH-treated H. pylori was determined by enzyme immunoassay and Western blot. The production of CagA and adherence of the treated bacteria were examined by enzyme immunoassay and light microscopy, respectively. To clarify how CagA is transported towards the inner membrane of the treated bacteria, the localization of CagA was analysed by immunoelectron microscopy. The proportion of hummingbird cells in the AGS cell line rapidly increased following the inoculation of acidic-pH-treated H. pylori but increased more slowly with neutral-pH-treated H. pylori, and the phenomenon correlated with the amount of phosphorylated CagA in AGS cells. CagA was densely localized near the inner membrane in the acidic-pH-treated bacterial cytoplasm, but this localization was not observed in the neutral-pH-treated bacterial cytoplasm, suggesting that CagA shifts from the centre to the peripheral portion of the cytoplasm as a result of an extracellular decrease in pH. This phenomenon depended on the presence of UreI, a proton-dependent urea channel, but not on the presence of urea. The pH treatments did not enhance CagA production or the adherence of the bacterium to AGS cells. The authors propose that H. pylori possesses a proton-dependent intracytoplasmic transport system that probably accelerates priming for CagA injection.

Matched MeSH terms: Gene Deletion
Fulltext Rapid and cost-effective antenatal diagnosis of haemoglobin Bart's hydrops foetalis syndrome using a duplex-polymerase chain reaction

Wee YC, Tan KL, Tan PC, Yap SF, Tan JAMA

Med J Malaysia, 2005 Oct;60(4):447-53.
PMID: 16570706

Haemoglobin Bart's hydrops foetalis syndrome (--SEA/--SEA) is not compatible with life and contributes to a majority of the hydropic foetuses in the Malaysian Chinese alpha-thalassaemia carriers who possess the 2-alpha-gene deletion in cis (--SEA/alphaalpha). A duplex-PCR which simultaneously amplifies a normal 136 bp sequence between the psialpha-alpha2-globin genes and a 730 bp Southeast Asian deletion-specific sequence (--SEA) between the psialpha2-theta1-globin genes was established. The duplex-PCR which detects the --SEA deletion in both chromosomes serves as a rapid and cost-effective confirmatory test in the antenatal diagnosis of Haemoglobin Bart's hydrops foetalis syndrome in Malaysia. In addition, the duplex-PCR is simple to perform as both the normal and deletion-specific alpha-globin gene sequences are amplified in the same PCR reaction.

Matched MeSH terms: Gene Deletion
Combination of SMN2 copy number and NAIP deletion predicts disease severity in spinal muscular atrophy

Watihayati MS, Fatemeh H, Marini M, Atif AB, Zahiruddin WM, Sasongko TH, et al.

Brain Dev, 2009 Jan;31(1):42-5.
PMID: 18842367 DOI: 10.1016/j.braindev.2008.08.012

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations in the SMN1 gene. The SMN2 gene is highly homologous to SMN1 and has been reported to be correlated with severity of the disease. The clinical presentation of SMA varies from severe to mild, with three clinical subtypes (type I, type II, and type III) that are assigned according to age of onset and severity of the disease. Here, we aim to investigate the potential association between the number of copies of SMN2 and the deletion in the NAIP gene with the clinical severity of SMA in patients of Malaysian origin. Forty-two SMA patients (14 of type I, 20 type II, and 8 type III) carrying deletions of the SMN1 gene were enrolled in this study. SMN2 copy number was determined by fluorescence-based quantitative polymerase chain reaction assay. Twenty-nine percent of type I patients carried one copy of SMN2, while the remaining 71% carried two copies. Among the type II and type III SMA patients, 29% of cases carried two copies of the gene, while 71% carried three or four copies of SMN2. Deletion analysis of NAIP showed that 50% of type I SMA patients had a homozygous deletion of exon 5 of this gene and that only 10% of type II SMA cases carried a homozygous deletion, while all type III patients carried intact copies of the NAIP gene. We conclude that there exists a close relationship between SMN2 copy number and SMA disease severity, suggesting that the determination of SMN2 copy number may be a good predictor of SMA disease type. Furthermore, NAIP gene deletion was found to be associated with SMA severity. In conclusion, combining the analysis of deletion of NAIP with the assessment of SMN2 copy number increases the value of this tool in predicting the severity of SMA.

Matched MeSH terms: Gene Deletion*
NAIP-deletion analysis in Malaysian patients with spinal muscular atrophy

Watihayati MS, M S W, Zabidi AM, A M H ZH, Tang TH, T H T, et al.

Kobe J Med Sci, 2007;53(4):171-5.
PMID: 17932457

Spinal Muscular Atrophy (SMA) is an autosomal recessive disease, which is characterized by degeneration of the anterior horn cells of the spinal cord. SMA is classified into 3 clinical subtypes, type I (severe), type II (intermediate), and type III (mild). Two genes, SMN1 and NAIP, have been identified as SMA-related genes. The SMN1 gene is now recognized as a responsible gene for the disease because it is deleted or mutated in most SMA patients. However, the role of the NAIP gene in SMA has not been fully clarified. To clarify the contribution of NAIP to the disease severity of SMA, we studied the relationship between NAIP-deletion and clinical phenotype in Malaysian patients. A total of 39 patients lacking SMN1 (12 type I, 19 type II, and 8 type III patients) were enrolled into this study. Seven out of 12 patients with type I SMA (approximately 60%) showed NAIP deletion. On the contrary, only 2 out of 20 type II patients and none of type III patients showed NAIP deletion. There was a statistically significant difference in NAIP-deletion frequency among the clinical subtypes (Fisher's exact probability test, p value = 0.014). In conclusion, according to our data that NAIP deletion was more frequent in type I SMA than in type II-III SMA, the NAIP gene may be a modifying factor for disease severity of SMA.

Matched MeSH terms: Gene Deletion*
A single, large deletion accounts for all the beta-globin gene mutations in twenty families from Sabah (North Borneo), Malaysia. Mutation in brief no. 240. Online

Thong MK, Rudzki Z, Hall J, Tan JA, Chan LL, Yap SF

Hum Mutat, 1999;13(5):413.
PMID: 10338100 DOI: 10.1002/(SICI)1098-1004(1999)13:5<413::AID-HUMU15>

Beta-thalassemia major is one of the commonest genetic disorders in South-East Asia. The spectrum of beta-thalassemia mutations in the various ethnic sub-populations on the island of Borneo is unknown. We studied 20 Dusun children from the East Malaysian state of Sabah (North Borneo) with a severe beta-thalassemia major phenotype, using a combination of Southern analysis, polymerase chain reaction analysis and direct sequencing. We found the children to be homozygous for a large deletion, which has a 5' breakpoint at position -4279 from the cap site of the beta-globin gene (HBB) with the 3' breakpoint located in a L1 family of repetitive sequences at an unknown distance from the beta-globin gene. This was similar to a recent finding of a large deletion causing beta-thalassemia first described in unrelated beta-thalassemia heterozygotes of Filipino descent. This report describes the first 20 families with homozygosity of the deletion causing a severe phenotype. It provides the first information on the molecular epidemiology of beta-thalassemia in Sabah. This finding has implications for the population genetics and preventative strategies for beta-thalassemia major for nearly 300 million individuals in South-East Asia.

Matched MeSH terms: Gene Deletion*
Fulltext Neonatal intrahepatic cholestasis caused by citrin deficiency in two Malaysian siblings: outcome at one year of life

Thong MK, Boey CC, Sheng JS, Ushikai M, Kobayashi K

Singapore Med J, 2010 Jan;51(1):e12-4.
PMID: 20200759

We report two Malaysian siblings with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). The younger sibling, a six-month-old Chinese girl, presented with prolonged neonatal jaundice, and was investigated for biliary atresia. Urine metabolic screen showed the presence of urinary-reducing sugars, and she was treated with a lactose-free formula. NICCD was suspected based on the clinical history, examination and presence of urinary citrulline. Mutation study of the SLC25A13 gene showed the compound heterozygotes, 851del4 and IVS16ins3kb, which confirmed the diagnosis of NICCD in the patient and her three-year-old female sibling, who also had unexplained neonatal cholestasis. Long-term dietary advice, medical surveillance and genetic counselling were provided to the family. The diagnosis of NICCD should be considered in infants with unexplained prolonged jaundice. DNA-based genetic testing of the SLC25A13 gene may be performed to confirm the diagnosis retrospectively. An awareness of this condition may help in early diagnosis using appropriate metabolic and biochemical investigations, thus avoiding invasive investigations in infants with neonatal cholestasis caused by NICCD.

Matched MeSH terms: Gene Deletion
Fulltext Evaluation of BRCA1 and BRCA2 mutations and risk-prediction models in a typical Asian country (Malaysia) with a relatively low incidence of breast cancer

Thirthagiri E, Lee SY, Kang P, Lee DS, Toh GT, Selamat S, et al.

Breast Cancer Res, 2008;10(4):R59.
PMID: 18627636 DOI: 10.1186/bcr2118

The cost of genetic testing and the limited knowledge about the BRCA1 and BRCA2 genes in different ethnic groups has limited its availability in medium- and low-resource countries, including Malaysia. In addition, the applicability of many risk-assessment tools, such as the Manchester Scoring System and BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) which were developed based on mutation rates observed primarily in Caucasian populations using data from multiplex families, and in populations where the rate of breast cancer is higher, has not been widely tested in Asia or in Asians living elsewhere. Here, we report the results of genetic testing for mutations in the BRCA1 or BRCA2 genes in a series of families with breast cancer in the multi-ethnic population (Malay, Chinese and Indian) of Malaysia.

Matched MeSH terms: Gene Deletion
Analyses of Epstein-Barr virus latent membrane protein-1 in Malaysian nasopharyngeal carcinoma: high prevalence of 30-bp deletion, Xho1 polymorphism and evidence of dual infections

Tan EL, Peh SC, Sam CK

J Med Virol, 2003 Feb;69(2):251-7.
PMID: 12683415

Nasopharyngeal carcinoma, a malignancy associated closely with Epstein-Barr virus (EBV), is prevalent among Chinese of Southern China origin. Epidemiological studies indicate a high prevalence of EBV in Asia with viral isolates having typical characteristics of the putative viral oncogene, latent membrane protein 1 (LMP-1), such as the loss of the Xho1 restriction site in Exon 1 and the 30-bp deletion in Exon 3. The EBV LMP-1 gene from throat washings of 120 nasopharyngeal carcinoma patients and 14 healthy individuals were analyzed. Similar analyses were also carried out on 30 and 12 postnasal space biopsies from nasopharyngeal carcinoma patients and healthy individuals, respectively. The 30-bp deletion was detected in 20% of nasopharyngeal carcinoma throat washes and in 100% of nasopharyngeal carcinoma postnasal space biopsies. Interestingly, 16% of the nasopharyngeal carcinoma biopsies possessed both the deleted and the undeleted variants, suggestive of dual infections. The notion of dual infections in nasopharyngeal carcinoma was further supported by the coexistence of both "F" and "f" (BamH1F region) EBV variants in 11% of the nasopharyngeal carcinoma biopsies. All of the throat washes and biopsies from the healthy controls showed the undeleted variant. The loss of the Xho1 restriction site was found with higher frequency both in throat washes and biopsies from patients with nasopharyngeal carcinoma. The discrepancy in the frequency of the 30-bp deletion between throat washes (20%) and postnasal space biopsies (100%) was an indication that this deletion is specific for viral isolates from primary tumour sites.

Matched MeSH terms: Gene Deletion*
High frequency of EBV association and 30-bp deletion in the LMP-1 gene in CD56 lymphomas of the upper aerodigestive tract

Tai YC, Kim LH, Peh SC

Pathol. Int., 2004 Mar;54(3):158-66.
PMID: 14989738

Natural killer (NK)/T-cell lymphomas are frequently associated with Epstein-Barr virus (EBV), and usually lack TCR gene rearrangement. Studies from Asia have reported frequent deletion in the LMP-1 gene in EBV-associated nasopharyngeal carcinoma (NPC). The present study aims to investigate LMP-1 and TCRgamma gene status in upper aerodigestive tract lymphomas. A total of 43 cases were classified into T-, B-, and NK/T-cell tumors based on the phenotype expressions of CD3(+)/CD20(-)/CD56(-), CD3(-)/CD20(+)/CD56(-), and CD3(+)/CD20(-)/CD56(+), respectively. The presence of EBV in the tumor was confirmed by EBV early RNA-in situ hybridization. LMP-1 gene deletion and TCR gamma gene rearrangement were analyzed by polymerase chain reaction on paraffin-embedded tissues. There were 20 NK/T-, eight T-, and 15 B-cell phenotype lymphomas in the present series, and EBV was detected in 19 (95%), two (25%), and three (20%) cases in the respective groups. All EBV+ cases carried 30-bp deletion in the LMP-1 gene, and two of the NK/T-cell cases were infected by both the wild type and deleted strains. Five (25%) of the NK/T-cell phenotype lymphomas showed rearranged TCR gamma gene. The present study revealed a high frequency of EBV association, and a high frequency of 30-bp deletion in the LMP-1 gene in the virus in the present series of lymphoma. The NK/T-phenotype lymphomas are comprised of both NK-cell and cytotoxic T-lymphocyte-derived tumors.

Matched MeSH terms: Gene Deletion
Malaysian siblings with friedreich ataxia and chorea: a novel deletion in the frataxin gene

Spacey SD, Szczygielski BI, Young SP, Hukin J, Selby K, Snutch TP

Can J Neurol Sci, 2004 Aug;31(3):383-6.
PMID: 15376485

BACKGROUND: Friedrich ataxia (FRDA1) is most often the result of a homozygous GAA repeat expansion in the first intron of the frataxin gene (FRDA gene). This condition is seen in individuals of European, North African, Middle Eastern and Indian descent and has not been reported in Southeast Asian populations. Approximately 4% of FRDA1 patients are compound heterozygotes. These patients have a GAA expansion on one allele and a point mutation on the other and have been reported to have an atypical phenotype.
OBJECTIVE: To describe a novel dinucleotide deletion in the FRDA gene in two Malaysian siblings with FRDA1.
SETTING: Tertiary referral university hospital setting.
PATIENTS AND METHODS: A previously healthy 10-year-old Malaysian boy, presented with fever, lethargy, headaches, dysarthria, dysphagia, vertigo and ataxia which developed over a one week period. His neurological exam revealed evidence of dysarthria and ataxia, mild generalized weakness and choreoform movements of the tongue and hands. His reflexes were absent and Babinski sign was present bilaterally. A nine-year-old sister was found to have mild ataxia but was otherwise neurologically intact.
RESULTS: Molecular genetic studies demonstrated that both siblings were compound heterozygotes with a GAA expansion on one allele and a novel dinucleotide deletion on the other allele.
CONCLUSIONS: We describe a novel dinucleotide deletion in the first exon of the FRDA gene in two siblings with FRDA1. Additionally this is the first report of FRDA1 occurring in a family of southeast Asian descent, it demonstrates intrafamilial phenotypic variability, and confirms that atypical phenotypes are associated with compound heterozygosity.

Matched MeSH terms: Gene Deletion*
Molecular study and genotype/phenotype correlation of β Thalassemia in Malaysia

Sivalingam M, Looi ML, Zakaria SZ, Hamidah NH, Alias H, Latiff ZA, et al.

Int J Lab Hematol, 2012 Aug;34(4):377-82.
PMID: 22335963 DOI: 10.1111/j.1751-553X.2012.01405.x

INTRODUCTION: To study the ß-gene mutations spectrum, the genotype/phenotype correlation, the modulatory effect of co-inherited factors such as α-gene mutations and of Xmn1 polymorphism in a large cohort of Malaysian patients.
METHODS: A total of 264 cases clinically diagnosed as Thalassemia major (TM) (111), Thalassemia intermedia (21), HbE-β Thalassemia (131), and 1 HbE homozygous were studied. The detection of α and ß gene mutations and characterization of Xmn1 polymorphism were performed by multiplex PCR, amplification refractory mutation system (ARMS), DNA sequencing, and restriction fragment length polymorphism (RFLP)-PCR.
RESULTS: A total of 19 ß Thalassemia mutations were characterized. CD26 and CD41/42 were the most common found in the Malay and Chinese population, respectively. The sensitivity of the clinical diagnosis for β TM, thalassemia intermedia, and HbE/β thalassemia was 94.0%, 15.2%, and 89.2%, respectively. Patients with Xmn1 heterozygosity [+/-] required less frequent transfusion compared with those without the polymorphism. Co-inheritance of α-thalassemia alleviates the severity of HbE-β thalassemia in our cohort.
CONCLUSION: Molecular analysis should be used for a better diagnosis and management of β thalassemia.

Matched MeSH terms: Gene Deletion
Fulltext Epstein-Barr virus latent membrane protein-1 (LMP-1) 30-bp deletion and Xho I-loss is associated with type III nasopharyngeal carcinoma in Malaysia

See HS, Yap YY, Yip WK, Seow HF

World J Surg Oncol, 2008;6:18.
PMID: 18275617 DOI: 10.1186/1477-7819-6-18

Nasopharyngeal carcinoma (NPC) is a human epithelial tumour with high prevalence amongst Chinese in Southern China and South East Asia and is associated with the Epstein-Barr virus (EBV). The viral genome harbours an oncogene, namely, the latent membrane protein 1 (LMP1) gene and known variants such as the 30-bp deletion and loss of XhoI restriction site have been found. Less is known about the relationship between these variants and the population characteristics and histological type.

Matched MeSH terms: Gene Deletion*
RecA mediated spontaneous deletions of the icaADBC operon of clinical Staphylococcus epidermidis isolates: a new mechanism of phenotypic variations

Nuryastuti T, Henny C, Henk JB, Roel K, Abu TA, Bastiaan PK

Med J Malaysia, 2008 Jul;63 Suppl A:97.
PMID: 19025002

Phenotypic variation in biofilm formation is common in clinical isolates of S. epidermidis. In the current study, nearly 5% of all clinical isolates analysed showed phenotypic variation in biofilm forming ability and electrophoretic mobility (EM). This is the first report of S. epidermidis strains irreversibly switching from biofilm-positive to biofilm-negative phenotype by spontaneous deletion of icaADBC genes which represents a new, possibly common mechanism of phenotypic variation.

Matched MeSH terms: Gene Deletion*
Fulltext Prevalence of mitochondrial DNA common deletion in patients with gliomas and meningiomas: A first report from a Malaysian study group

Mohamed Yusoff AA, Mohd Khair SZN, Abd Radzak SM, Idris Z, Lee HC

J Chin Med Assoc, 2020 Sep;83(9):838-844.
PMID: 32732530 DOI: 10.1097/JCMA.0000000000000401

BACKGROUND: The 4977-bp common deletion (mtDNA) is a well-established mitochondrial genome alteration that has been described in various types of human cancers. However, to date, no studies on mtDNA in brain tumors have been reported. The present study aimed to determine mtDNA prevalence in common brain tumors, specifically, low- and high-grade gliomas (LGGs and HGGs), and meningiomas in Malaysian cases. Its correlation with clinicopathological parameters was also evaluated.
METHODS: A total of 50 patients with pathologically confirmed brain tumors (13 LGGs, 20 HGGs, and 17 meningiomas) were enrolled in this study. mtDNA was detected by using polymerase chain reaction (PCR) technique and later confirmed via Sanger DNA sequencing.
RESULTS: Overall, mtDNA was observed in 16 (32%) patients and it was significantly correlated with the type of tumor group and sex, being more common in the HGG group and in male patients.
CONCLUSION: The prevalence of mtDNA in Malaysian glioma and meningioma cases has been described for the first time and it was, indeed, comparable with previously published studies. This study provides initial insights into mtDNA in brain tumor and these findings can serve as new data for the global mitochondrial DNA mutations database.

Matched MeSH terms: Gene Deletion*
Fulltext Screening of 22q11.2DS Using Multiplex Ligation-Dependent Probe Amplification as an Alternative Diagnostic Method

Maran S, Faten SA, Lim SE, Lai KS, Ibrahim WPW, Ankathil R, et al.

Biomed Res Int, 2020;2020:6945730.
PMID: 33062692 DOI: 10.1155/2020/6945730

Background: The 22q11.2 deletion syndrome (22q11.2DS) is the most common form of deletion disorder in humans. Low copy repeats flanking the 22q11.2 region confers a substrate for nonallelic homologous recombination (NAHR) events leading to rearrangements which have been reported to be associated with highly variable and expansive phenotypes. The 22q11.2DS is reported as the most common genetic cause of congenital heart defects (CHDs).
Methods: A total of 42 patients with congenital heart defects, as confirmed by echocardiography, were recruited. Genetic molecular analysis using a fluorescence in situ hybridization (FISH) technique was conducted as part of routine 22q11.2DS screening, followed by multiplex ligation-dependent probe amplification (MLPA), which serves as a confirmatory test.
Results: Two of the 42 CHD cases (4.76%) indicated the presence of 22q11.2DS, and interestingly, both cases have conotruncal heart defects. In terms of concordance of techniques used, MLPA is superior since it can detect deletions within the 22q11.2 locus and outside of the typically deleted region (TDR) as well as duplications.
Conclusion: The incidence of 22q11.2DS among patients with CHD in the east coast of Malaysia is 0.047. MLPA is a scalable and affordable alternative molecular diagnostic method in the screening of 22q11.2DS and can be routinely applied for the diagnosis of deletion syndromes.

Matched MeSH terms: Gene Deletion

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