产前诊断先天性畸形及遗传病.pdfVIP

Prenatal Diagnosis for Congenital Malformations and Genetic Disorders Daljit Singh, MBBS, MS, DSc, Professor Emeritis, Department of Ophthalmology, Guru Nanak Dev University, Amritsar, India; Director, Daljit Singh Eye Hospital Jai Rup Singh, PhD, First Vice Chancellor, Central University of Punjab, Bathinda, India; Vanita Vanita, MSc, PhD, Reader Head, Centre for Genetic Disorders, Guru Nanak Dev University, Amritsar, Punjab, India Updated: Apr 9, 2010 Introduction Congenital abnormalities account for 20-25% of perinatal deaths. Now, many genetic and other disorders can be diagnosed early in pregnancy. Prenatal diagnosis uses various noninvasive and invasive techniques to determine the health of, the condition of, or any abnormality in an unborn fetus. These techniques are outlined below. Noninvasive techniques  Fetal visualization o Ultrasound o Fetal echocardiography o Magnetic resonance imaging (MRI) o Radiography  Screening for neural tube defects (NTDs) –  Measuring maternal serum alpha-fetoprotein (MSAFP)  Screening for fetal Down syndrome o Measuring MSAFP o Measuring maternal unconjugated estriol  Measuring maternal serum beta-human chorionic gonadotropin (HCG)  Separation of fetal cells from the mothers blood Invasive techniques  Fetal visualization o Embryoscopy o Fetoscopy  Fetal tissue sampling o Amniocentesis o Chorionic villus sampling (CVS) o Percutaneous umbilical blood sampling (PUBS) o Percutaneous skin biopsy  Other organ biopsies, including muscle and liver biopsy  Preimplantation biopsy of blastocysts obtained by in vitro fertilization   Cytogenetic investigations o Detection of chromosomal aberrations