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A/Prof Samuel Chong Siong Chuan

  • Associate Professor, Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore
FACMG, American College of Medical Genetics (USA), DipABMG, American Board of Medical Genetics (USA), BSc (Hons) (Singapore), MSc (British Columbia), PhD (Baylor Coll Med)


A/Prof Samuel Chong joined the Department of Paediatrics, Yong Loo Lin School of Medicine, NUS as a Senior Lecturer in 1989 and became Associate Professor in 2003. He is the Director of the Preimplantation Genetic Diagnosis Centre at the Department of Obstetrics and Gynaecology, NUH. He also serves as Scientific Advisor to the Molecular Diagnosis Centre and the Clinical Cytogenetics Service of the Department of Laboratory Medicine, NUH.

Dr Chong received his undergraduate education at NUS and graduated with a BSc degree with honours in 1986. That same year, he left Singapore to pursue a Master’s degree at the University of British Columbia in Vancouver, Canada, under a CIDA (Canadian International Development Agency) scholarship. In 1989, he moved south to the United States of America to pursue further scientific training at the Baylor College of Medicine in Houston, Texas. While there, he stumbled upon and fell in love with the fascinating field of human and molecular genetics. He successfully defended his graduate thesis and was conferred the PhD degree in 1994.
He joined the National Human Genome Research Institute, National Institutes of Health in Bethesda, Maryland, as a Visiting Fellow in 1994. In 1995, he was concurrently appointed as Research Instructor at the Institute for Molecular and Human Genetics and Department of Paediatrics, Georgetown University Medical Centre, in Washington, D.C..

In 1997, Dr Chong moved to the McKusick-Nathans Institute of Genetic Medicine at the Johns Hopkins University School of Medicine in Baltimore, Maryland to take up an appointment as an Assistant Professor with a joint appointment in the Department of Gynaecology and Obstetrics.

At the turn of the century after more than a decade away in North America, Dr Chong returned to Singapore to re-join his undergraduate alma mater as a faculty member and he has been there ever since. His research interests are in finding innovative solutions to molecular diagnostic challenges.

His research interests revolve around developing innovative molecular toolkits for preimplantation, prenatal and postnatal diagnostic testing and screening of challenging genetic and genomic disorders. He has published more than 150 papers in local, regional, and international journals. He also teaches undergraduate life sciences students in human genetics and genomics.

Other Qualifications:
FACMG, American College of Medical Genetics, USA (2000)
DipABMG, American Board of Medical Genetics, USA (1999)

As Principal Investigator
  • 2005 – 2019: Preimplantation Genetic Diagnosis
    • Funding Agency: MOH HSDP
  • 2016 – 2018: Highly Polymorphic Multiplex Marker Panel and Robust Mutation Detection Strategy Universally Applicable to Preimplantation Genetic Diagnosis of Huntington Disease
    • Funding Agency: NUHS
  • 2015 – 2018: A Unified Mutation Detection and Linked Haplotype Assay for Reliable and Accurate Preimplantation Genetic Diagnosis of Fragile X Syndrome
    • Funding Agency: NUHS
  • 2014 – 2017: Regulation/Role of MAPKAPK3, an IRF6-Regulated Gene, in Epithelial/Skin Formation
    • Funding Agency: NUHS
  • 2012 – 2015: Regulation and Role of CYR61, a Putative Downstream Target Gene of IRF6, in Gastrulation
    • Funding Agency: ARF
  • 2012 – 2015: Development of a Tool to Predict Response of Patients to Fluorouracil/Platinum Drugs
    • Funding Agency: A*STAR - SERC
  • 2009 – 2014: International Genetic Epidemiology of Oral Clefts (renewal)
    • Funding Agency: NIDCR/NIH, USA
  • 2007 – 2010: Development of a Homogeneous Assay Platform Generally Applicable to the Molecular Diagnosis of Dynamic Mutation Disorders
    • Funding Agency: NMRC
  • 2007 – 2010: Genetic Epidemiology of Pre-Eclampsia: Maternal & Paternal Genetic Variation at the HLAG & KIR2DL4 Gene Loci & Susceptibility to Disease
    • Funding Agency: NMRC
  • 2007 – 2010: Function and Regulatory Control of the Van Der Woude Syndrome Gene IRF6 in the Zebrafish Model
    • Funding Agency: BMRC
  • 2004 – 2009: International Genetic Epidemiology of Oral Clefts
    • Funding Agency: NIDCR/NIH, USA
  • 2005 – 2008: Automated Mutation/SNP Lab-On-A-Chip Devices for Molecular Diagnostics and Genomic Research
    • Funding Agency: BMRC
  • 2003 – 2008: Establishment and Validation of a Preimplantation Genetic Diagnosis Program in Singapore
    • Funding Agency: BMRC
  • 2004 – 2007: Genomic and In Situ Expression Analyses of the Zebrafish Homologs of TWIST, the Gene Mutated in Saethre-Chotzen Syndrome
    • Funding Agency: ARF
  • 2003 – 2006: Molecular Basis of Nonsense-Mediated mRNA Decay (NMD) in Beta-Thalassemia
    • Funding Agency: NMRC
  • 2002 – 2005: Single Nucleotide Polymorphisms (SNPs) in the MDR1 Gene in the Three Ethnic Groups in Singapore – Correlating Polymorphisms/Haplotypes with Drug Transport in Search of Functional SNPs
    • Funding Agency: NMRC
  • 2002 – 2005: Retroviral-Mediated Strategies for In Vivo Expression Reporting and Isolation of Novel Zebrafish Genes Important in Human Development and Disease
    • Funding Agency: ARF
  • 2000 – 2003: Simplified Molecular Diagnostic Testing for Fragile X Mental Retardation Syndrome
    • Funding Agency: NMRC
  • 1999 – 2002: Development of Simplified and Highly Sensitive Molecular Diagnostic Testing for Alpha Thalassemia
    • Funding Agency: NMRC
  • United States Patent No. US 9,365,892 .B2. Title: Screening Method for Trinucleotide Repeat Sequences.  Awarded 14 Jun 2016.
  • International Patent Application No, PCT/SG2010/000396.  Title: Screening Method for Trinucleotide Repeat Sequences.  Filed on 15 Oct 2010.
  • US Provisional Patent Application No, 61/252,182.  Title: Simplified Methylation-Specific PCR Analysis of FMR1 CGG Repeat Expansions.  (09206N-US/PRV).  Filed on 16 Oct 2009.
  • US Provisional Patent Application No, 61/107,376.  Title: Identification of a Genetic Factor (HLA-G*0106) Associated with Increased Risk of Pre-Eclampsia.  (CHONG SS 01-US/PRV).  Filed on 22 Oct 2008.
Editorial Boards:
  • Associate Editor, BMC Medical Genetics
  • Review Editor, Frontiers in Applied Genetic Epidemiology


  • 1996: NIH Fellows' Award for Research Excellence, National Institutes of Health, Bethesda, MD, USA
  • 1994: March of Dimes Birth Defects Foundation Award for Research Excellence in the Area of Genetics and Birth Defects, 35th Annual National Student Research Forum, Galveston, TX, USA
  • 1994: Dist Univ. of Texas Medical Branch Dept. of Human Biological Chemistry and Genetics Biochemistry/Molecular Biology Award, 35th Annual National Student Research Forum, Galveston, TX, USA
  • 1993: ASHG Predoctoral Clinical Research Award, 43rd Annual Meeting of American Society of Human Genetics, New Orleans, LA, USA
  • 1993: First Place Poster Award, 5th Annual Graduate Student Research Symposium, Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, TX, USA
  • 1984: Singapore Institute of Biology Book Prize, National University of Singapore, SINGAPORE

Journals & Publications

  1. Chong SS, Kristjansson K, Cota J, Handyside AH, Hughes MR (1993). Preimplantation prevention of X-linked disease: reliable and rapid sex determination of single human cells by restriction analysis of simultaneously amplified ZFX and ZFY sequences. Human Molecular Genetics, 2(8):1187-91.
  2. Kristjansson K, Chong SS, Van den Veyver IB, Snabes MC, Hughes MR (1994). Preimplantation analyses for dystrophin gene deletions after single cell whole genome amplification. Nature Genetics, 6:19-24. doi:10.1038/ng0194-19
  3. Chong SS, McCall AE, Subramony SB, Cota J, Orr HT, Hughes MR, Zoghbi HY (1995). Gametic and somatic tissue-specific heterogeneity of the expanded SCA1 CAG repeat in spinocerebellar ataxia type 1. Nature Genetics, 10(3):344-50. doi: 10.1038/ng0795-344
  4. Chong SS, Tanigami A, Roschke AV, Ledbetter DH (1996). 14-3-3 epsilon has no homology to LIS1 and lies telomeric to it on chromosome 17p13.3 outside the Miller-Dieker syndrome chromosome region. Genome Research, 6(8):735-41.
  5. Chong SS, Pack SD, Roschke AV, Tanigami A, Carrozzo R, Smith ACM, Dobyns WB, Ledbetter DH (1997). A revision of the lissencephaly and Miller-Dieker syndrome critical regions in chromosome 17p13.3. Human Molecular Genetics, 6(2):147-55.
  6. Lo Nigro C, Chong SS, Smith ACM, Dobyns WB, Carrozzo R, Ledbetter DH (1997). Point mutations and an intragenic deletion in LIS1, the lissencephaly causative gene in isolated lissencephaly sequence and Miller-Dieker syndrome. Human Molecular Genetics, 6(2):157-64. 
  7. Chong SS, Almqvist E, Telenius H, La Tray L, Nichols K, Bourdelat-Parks B, … Hayden MR (1997).  Contribution of DNA sequence and CAG size to mutation frequencies of intermediate alleles for Huntington disease: evidence from single sperm analyses. Human Molecular Genetics, 6(2):301-9.
  8. Higgs DR, Ayyub H, Chong SS (1999).  The --THAI and --FIL determinants of  thalassemia in Taiwan.  American Journal of Hematology, 60(1):80-1.
  9. Chong SS, Boehm CD, Higgs DR, Cutting GR (2000). Single-tube multiplex-PCR screen for common deletional determinants of -thalassemia. Blood, 95(1):360-2.
  10. Tan ASC, Quah TC, Low PS, Chong SS (2001). A rapid and reliable seven-deletion multiplex-PCR assay for -thalassemia. Blood, 98(1):250-1.
  11. Wang W, Kham SKY, Yeo GH, Quah TC, Chong SS (2003). Multiplex-minisequencing screen for common Southeast Asian and Indian -thalassemia mutations. Clinical Chemistry, 49(2):209-18.
  12. Wang W, Ma ESK, Chan AYY, Chui DHK, Chong SS (2003). Multiplex-minisequencing screen for seven Southeast Asian non-deletional -thalassemia mutations. Clinical Chemistry, 49:800-3. doi: 10.1373/49.5.800
  13. Wang W, Ma ESK, Chan AYY, Prior J, Erber WN, Chan LC, … Chong SS (2003). Single-tube multiplex-PCR screen for anti-3.7 and anti-4.2 -globin gene triplications. Clinical Chemistry, 49(10):1679-82. doi: 10.1373/49.10.1679
  14. Wang W, Chan AYY, Chan LC, Ma ESK, Chong SS (2005). Unusual rearrangement of the -globin gene cluster containing both the -3.7 and anti4.2 crossover junctions – clinical diagnostic implications and possible mechanisms. Clinical Chemistry, 51:2167-70. doi: 10.1373/clinchem.2005.054189
  15. Law HY, Luo HY, Wang W, Ho JFV, Najmabadi H, Ng ISL, …  Chong SS (2006). Determining the cause of patchwork HBA1 and HBA2 genes: recurrent gene conversion or crossing over fixation events? Haematologica, 91(3):297-302.
  16. Zhou Y, Lum JMS, Yeo GH, Kiing J, Tay SKH, Chong SS (2006). Simplified molecular diagnosis of fragile X syndrome by fluorescent methylation specific PCR and GeneScan analysis. Clinical Chemistry, 52(8):1492-500. doi: 10.1373/clinchem.2006.068593
  17. Teo CRL, Wang W, Law HY, Lee CG, Chong SS (2008). Single-step scalable throughput molecular screening for Huntington disease. Clinical Chemistry, 54(6):964-72. doi: 10.1373/clinchem.2007.096503.
  18. Wang W, Law HY, Chong SS (2009). Detection and discrimination between deletional and non-deletional Prader-Willi and Angelman syndromes by methylation-specific quantitative melting analysis. Journal of Molecular Diagnostics, 11(5):446-9. doi: 10.2353/jmoldx.2009.090015
  19. Ng JK, Wang W, Liu W-T, Chong SS (2010). Spatially addressable bead-based biosensor for rapid detection of beta-thalassemia mutations. Analytica Chimica Acta, 658(2):193-6. doi: 10.1016/j.aca.2009.11.020
  20. Teo CRL, Law HY, Lee CG, Chong SS (2012). Screening for CGG repeat expansion in the FMR1 gene by melting curve analysis of combined 5’ and 3’ direct triplet-primed PCRs. Clinical Chemistry, 58(3):568-79. doi: 10.1373/clinchem.2011.174615
  21. Teo CRL, Rajanbabu IS, Lee CG, Law HY, Chong SS (2013). Methylation-specific triplet-primed PCR and melting curve analysis as a rapid screening tool for identifying actionable FMR1 genotypes.  Clinical Chemistry, 59(11):1668-70. doi: 10.1373/clinchem.2013.206771
  22. Omoumi A, Lee CGL, Wang Z, Yeow V, Cheng J, Wu-Chou YH, … Chong SS (2013). Fetal polymorphisms at the ABCB1-transporter gene locus are associated with susceptibility to non-syndromic oral cleft malformations. European Journal of Human Genetics, 21(12):1436-41. doi: 10.1038/ejhg.2013.25
  23. Lian M, Rajan-Babu IS, Singh K, Lee CG, Law HY, Chong SS (2015). Efficient and highly sensitive screen for myotonic dystrophy type 1 using a one-step triplet-primed PCR and melting curve assay. Journal of Molecular Diagnostics, 17(2):128-35. doi: 10.1016/j.jmoldx.2014.10.001
  24. Rajan-Babu IS, Teo CRL, Lian M, Lee CG, Law HY, Chong SS (2015). Single-tube methylation-specific duplex-PCR assay for rapid and accurate diagnosis of Fragile X Mental Retardation 1-related disorders. Expert Review of Molecular Diagnostics, 15(3):431-41. doi: 10.1586/14737159.2015.1001749
  25. Rajan-Babu IS, Law HY, Yoon CS, Lee CG, Chong SS (2015). Simplified strategy for rapid first-line screening of fragile X syndrome – closed-tube triplet-primed PCR and amplicon melt peak analysis.  Expert Reviews in Molecular Medicine, 17:e7. doi: 10.1017/erm.2015.5
  26. Chen M, Loh SF Yu SL, Nair S, Tan HH, Nadarajah S, Wong PC, … Chong SS (2015). Rapid and reliable preimplantation genetic diagnosis of common Hb Bart’s hydrops fetalis syndrome and Hb H disease determinants using an enhanced single-tube decaplex PCR assay. American Journal of Hematology, 90(9):E194-6. doi: 10.1002/ajh.24077
  27. Zhao M, Chen M, Lee CG, Chong SS (2016). Identification of novel microsatellite markers <1 Mb from the HTT CAG repeat and development of a single-tube tridecaplex PCR panel of highly polymorphic markers for preimplantation genetic diagnosis of Huntington disease. Clinical Chemistry, 62(8):1096-105. doi: 10.1373/clinchem.2016.255711
  28. Chen M, Zhao M, Lee CG, Chong SS (2016). Identification of microsatellite markers <1 Mb from the FMR1 CGG repeat and development of a single-tube tetradecaplex PCR panel of highly polymorphic markers for preimplantation genetic diagnosis of fragile X syndrome. Genetics in Medicine, 18(9):869-75. doi: 10.1038/gim.2015.185
  29. Rajan-Babu I-S, Chong SS (2016). Molecular correlates and recent advancements in the diagnosis and screening of FMR1-related disorders. Genes, 7(10):87. doi: 10.3390/genes7100087
  30. Lian M, Zhao M, Lee CG, Chong SS (2017). Single-tube dodecaplex PCR panel of polymorphic microsatellite markers closely linked to the DMPK CTG repeat for preimplantation genetic diagnosis of myotonic dystrophy type 1. Clinical Chemistry, 63(6):1127-1140. doi: 10.1373/clinchem.2017.271528
  31. Zhao M, Chen M, Tan AS, Cheah FS, Mathew J, Wong PC, Chong SS (2017). Single-tube tetradecaplex panel of highly polymorphic microsatellite markers <1 Mb from F8 for simplified preimplantation genetic diagnosis of haemophilia A. Journal of Thrombosis and Haemostasis, 15(7):1473-1483. doi: 10.1111/jth.13685
  32. Rajan-Babu IS, Lian M, Cheah FS, Chen M, Tan AS, Prasath EB, … Chong SS (2017). FMR1 CGG repeat expansion mutation detection and linked haplotype analysis for reliable and accurate preimplantation genetic diagnosis of fragile X syndrome. Expert Reviews in Molecular Medicine, 19:e10. doi: 10.1017/erm.2017.10

Professional Memberships

  • Asia Pacific Society of Human Genetics (APSHG)
  • Society of Chinese Bioscientists in America (SCBA)
  • European Society of Human Genetics (ESHG)
  • Preimplantation Genetic Diagnosis International Society (PGDIS)
  • Asia-Pacific Initiative on Reproduction (ASPIRE)


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