Budsaba Rerkamnuaychoke

Multilocus association of genetic variants in MLL, CREBBP, EP300, and TOP2A with childhood acute lymphoblastic leukemia in hispanics from Texas

Background: Hispanic children have both a higher incidence and a poorer outcome in acute lymphoblastic leukemia (ALL). Moreover, a higher incidence for therapy-related acute myeloid leukemia with 11q23 translocations after treatment with topoisomerase II (topo II) inhibitors has been observed in Hispanic children with ALL. We sought to determine the potential role of genetic variants within the topoisomerase IIα gene (TOP2A), within the mixed lineage leukemia gene (MLL) and two of its translocation partners, cyclin AMP response element-binding protein gene (CREBBP) and E1A binding protein gene (EP300) in the increased sensitivity of Hispanic children with ALL to topo II inhibitors. Methods: Fifty-two tagged single nucleotide polymorphisms (SNP) covering the four genes were genotyped in 241 samples (66 children with ALL and 175 age matched controls) of self-identified Hispanic origin. Results: Two SNPs within MLL (rs525549 and rs6589664) and three SNPs within EP300 (rs5758222, rs7286979, and rs20551) were significantly associated with ALL (P = 0.001–0.04). A significant gene-dosage effect for increasing numbers of potential high-risk genotypes (OR = 16.66; P = 2 × 10−5) and a major haplotype significantly associated with ALL (OR = 5.68; P = 2 × 10−6) were found. Replication in a sample of 137 affected White children and 239 controls showed that only rs6589664 (MLL) was significantly associated in this ethnic group. Conclusions: Our findings indicate that the association between ALL and common genetic variants within MLL and EP300 is population specific. Impact: Replication of our findings in independent Hispanic populations is warranted to elucidate the role of these variants in ALL susceptibility and define their importance in the ethnic specific differences in ALL risk. Cancer Epidemiol Biomarkers Prev; 20(6); 1204–12. ©2011 AACR.

DNA database of populations from different parts in the Kingdom of Thailand

The polymorphism of 15 short tandem repeat (STR) loci-D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA from AmpFlSTR Identifiler PCR amplification kit were analysed in 929 unrelated individuals living in the north, northeast, central and south of Thailand. The comparison between these four subpopulations demonstrated that subpopulations in the north and northeast were different in two loci from all paired groups while those in the north, central and south were closely related. The inter-population comparisons between combined Thai population and other ethnic groups including Eastern Chinese, Japanese, Iraq and Egyptian revealed that Eastern Chinese and Thai were closely related.

Diagnosis of four chromosome abnormalities of unknown origin by chromosome microdissection and subsequent reverse and forward painting

A molecular cytogenetic method consisting of chromosome microdissection and subsequent reverse/forward chromosome painting is a powerful tool to identify chromosome abnormalities of unknown origin. We present 4 cases of chromosome structural abnormalities whose origins were ascertained by this method. In one MCA/MR patient with an add(5q)chromosome, fluorescence in situ hybridization (FISH), using probes generated from a microdissected additional segment of the add(5q) chromosome and then from a distal region of normal chromosome 5, confirmed that the patient had a tandem duplication for a 5q35-qter segment. Similarly, we ascertained that an additional segment of an add(3p) chromosome in another MCA/MR patient had been derived from a 7q32-qter segment. In a woman with a history of successive spontaneous abortions and with a minute marker chromosome, painting using microdissected probes from the whole marker chromosome revealed that it was i(15)(p10) or psu dic(15;15)(q11;q11). Likewise, a marker observed in a fetus was a ring chromosome derived from the paracentromeric region of chromosome 19. We emphasize the value of the microdissection-based chromosome painting method in the identification of unknown chromosomes, especially for marker chromosomes. The method may contribute to a collection of data among patients with similar or identical chromosome abnormalities, which may lead to a better clinical syndrome delineation.

Y-chromosomal STR haplotypes in Central Thai population

12 Y-STR loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS438, DYS439 and DYS437) were typed with PowerPlex Y System (Promega, USA) in a total sample of 501 unrelated males from the central part of Thailand. Allele frequencies and gene diversity for each Y-STR locus were determined. Haplotype diversity from the combined 12 Y-STR loci was 0.9996. The present results can be used as Thai ethnic genetic information resources in routine forensic analysis.

Magnetic Nanoparticles PCR Enzyme-Linked Gene Assay for Quantitative Detection of BCR/ABL Fusion Gene in Chronic Myelogenous Leukemia

Magnetic nanoparticles (MNPs) have been widely used in medical diagnostic research. In this work, two technologies, MNPs and polymerase chain reaction (PCR), were combined to increase detection sensitivity and specificity. A novel technique based on the MNPs‐PCR enzyme‐linked gene assay (MELGA) was developed for detection of the BCR/ABL abnormal gene in chronic myelogenous leukemia (CML) patients.

Mutation Screening and Association Study of the Folylpolyglutamate Synthetase (FPGS) Gene with Susceptibility to Childhood Acute Lymphoblastic Leukemia.

BACKGROUND Folylpolyglutamate synthetase (FPGS), an important enzyme in the folate metabolic pathway, plays a central role in intracellular accumulation of folate and antifolate in several mammalian cell types. Loss of FPGS activity results in decreased cellular levels of antifolates and consequently to polyglutamatable antifolates in acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS During May 1997 and December 2003, 134 children diagnosed with ALL were recruited from one hospital in Thailand. We performed a mutation analysis in the coding regions of the FPGS gene and the association between single nucleotide polymorphisms (SNPs) within FPGS in a case-control sample of childhood ALL patients. Mutation screening was conducted by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and subsequently with direct sequencing (n=72). Association analysis between common FPGS variants and ALL risk was done in 98 childhood ALL cases and 95 healthy volunteers recruited as controls. RESULTS Seven SNPs in the FPGS coding region were identified by mutation analysis, 3 of which (IVS13+55C>T, g.1297T>G, and g.1508C>T) were recognized as novel SNPs. Association analysis revealed 3 of 6 SNPs to confer significant increase in ALL risk these being rs7039798 (p= 0.014, OR=2.14), rs1544105 (p=0.010, OR= 2.24), and rs10106 (p=0.026, OR= 1.99). CONCLUSIONS These findings suggested that common genetic polymorphisms in the FPGS coding region including rs7039789, rs1544105, and rs10106 are significantly associated with increased ALL risk in Thai children.

Intrauterine growth retardation fetus with trisomy 16 mosaicism.

Fetal trisomy 16 is considered uniformly lethal early in gestation. It has been reported to be associated with the variability of clinical features and outcomes. Mosaic trisomy 16 leads to a high risk of abnormality in prenatal cases. Intrauterine growth retardation (IUGR) is a common outcome of mosaic trisomy 16. Herein, we report on the case of Thai male IUGR fetus with trisomy 16 mosaicism. The fetal body was too small. Postmortem investigation of placenta revealed the abnormality including small placenta with furcated cord insertion and single umbilical cord artery. Cytogenetic study demonstrated trisomy 16 that was found 100% in placenta and only 16% in the fetal heart while other organs had normal karyotype. In addition, cardiac and other internal organs examination revealed normal morphology.

Database of nine tetrameric STR loci--D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 in Thai population.

Allele distributions for the nine STR loci included in the AmpFlSTR Profiler Plus kit were evaluated in a Thai population of 300 unrelated individuals.

Thai population data on nine tetrameric STR loci — D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317 and D7S820

Allele frequencies for the nine STR loci included in the AmpFlSTR Profiler kit were determined in a Thai population of 100 unrelated individuals.

Forensic Genetic Analysis of Bone Remain Samples

DNA typing from degraded human remains is still challenging forensic DNA scientists not only in the prospective of DNA purification but also in the interpretation of established DNA profiles and data manipulation, especially in mass fatalities. In this report, we presented DNA typing protocol to investigate many skeletal remains in different degrees of decomposing. In addition, we established the grading system aiming for prior determination of the association between levels of decomposing and overall STR amplification efficacy. A total of 80 bone samples were subjected to DNA isolation using the modified DNA IQ™ System (Promega, USA) for bone extraction following with STR analysis using the AmpFLSTR Identifiler® (Thermo Fisher Scientific, USA). In low destruction group, complete STR profiles were observed as 84.4% whereas partial profiles and non-amplified were found as 9.4% and 6.2%, respectively. Moreover, in medium destruction group, both complete and partial STR profiles were observed as 31.2% while 37.5% of this group was unable to amplify. Nevertheless, we could not purify DNA and were unable to generate STR profile in any sample from the high destroyed bone samples. Compact bones such as femur and humerus have high successful amplification rate superior than loose/spongy bones. Furthermore, costal cartilage could be a designate specimen for DNA isolation in a case of the body that was discovered approximately to 3 days after death which enabled to isolate high quality and quantity of DNA, reduce time and cost, and do not require special tools such as freezer mill.