Speaker

Dr. Tuangsit Wataganara

Chief of the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology,

Faculty of Medicaine Siriraj Hospital, Mahidol University, Thailand

Speaker's Biography

Dr. Wataganara is an Associate Professor in the Division of Maternal Fetal Medicine, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand. He is board-certified in both Obstetrics and Gynecology and Maternal Fetal Medicine. He has a special research interest in non-invasive prenatal genetic diagnosis (Tufts-New England Medical Center, Boston, USA) and fetal interventions. He has over 30 publications related to fetal medicine in international peer-review journals in the past ten years. Among his several prestigious awards include an Outstanding Young Investigator Award from CNAPS III Meeting (the USA, 2003) and Shan S. Ratnam Young Gynecologist Award from 20th AOCOG Meeting (Japan, 2007). He is an executive director of Ian Donald Inter-University School of Medical His Fetal Therapy unit in Bangkok is one of the most active facilities of its kind in Asia.

Topic

Prenatal Cell-free DNA Screening for Trisomies 21, 18, 13, and 22q11.2 Deletion

Abstract

Faculty of Medicine Siriraj Hospital has developed and applied a comprehensive non-invasive prenatal test (NIPT) by using high-coverage, high-throughput targeted next-generation sequencing to estimate fetal fraction (FF), determine fetal sex, and detect common aneuploidies, typically involving chromosomes 13, 18, 21, X, and Y. With more liberal use of our own in-house NIPT, it is imperative to establish institutional guidelines based on published evidence and our own experiences to maximize the prenatal diagnostic process with this technology. In the first trimester of pregnancy (11 to 13 weeks of gestation), approximately 10% of cell-free DNA circulating in maternal circulation is contributed by placental trophoblastic apoptosis. The paradigm has been shifting toward applying NIPT as the primary screening test for fetal aneuploidy in the early first trimester of gestation as the residual risk of a typical chromosomal abnormality is very low after a low-risk call. Fetuses with major structural defects should receive invasive prenatal diagnosis tests because of substantially high false-negative NIPT (up to 8%) in this situation. Aberrations of FF itself have been linked with the subsequent development of placental-related disorders. Discovery and detailed analysis of extra-haplotype raises suspicion of hydatidiform mole, undiagnosed twinning/vanishing twins, and maternal mosaicism. When multiple chromosomal aberrations were found, the risk of a confirmed malignancy was considerably high. Referral for extensive oncologic examination is recommended and may be guided by tumor-specific hallmarks in the NIPT profile.