《医学遗传学 Medical Genetics》课程授课教案（PPT课件讲稿）第十八章 遗传疾病的诊断（三）

Medical Genetics 18疾病的产前诊新 Prenatal iagnosis of isease

Medical Genetics 18 疾病的产前诊断 Prenatal Diagnosis of Disease

Medical Genetics Genetic diseases and congenita malformations occur in approximately 2 to 5 of all live births, account for up to 30% of paediatric admissions to hospital, and are an important cause of death under the age of 15 years

Medical Genetics Genetic diseases and congenital malformations occur in approximately 2 to 5 % of all live births, account for up to 30% of paediatric admissions to hospital, and are an important cause of death under the age of 15 years

Medical Genetics Furthermore the psychological stress on families with children with serious genetic disorders is incalculable. Until gene therapy becomes a practical reality, the only option available for the control of genetic disease is prenatal diagnosis

Medical Genetics Furthermore, the psychological stress on families with children with serious genetic disorders is incalculable. Until gene therapy becomes a practical reality, the only option available for the control of genetic disease is prenatal diagnosis

Medical Genetics 1. Indications for prenatal diagnosis The use of prenatal diagnosis is determined by balancing the risk of the birth of an abnormal child against the risk of an investigative procedure

Medical Genetics 1. Indications for prenatal diagnosis The use of prenatal diagnosis is determined by balancing the risk of the birth of an abnormal child against the risk of an investigative procedure

Medical Genetics The general indications of prenatal diagnosis include maternal age and the results of noninvasive serum biochemical screening

Medical Genetics The general indications of prenatal diagnosis include maternal age and the results of noninvasive serum biochemical screening

Medical Genetics Specific indications include a positive family history and the birth of a previous child affected by a particular genetic disease

Medical Genetics Specific indications include a positive family history and the birth of a previous child affected by a particular genetic disease

Medical Genetics 2. Methods for obtaining fetal tissues for prenatal diagnosis To perform prenatal diagnosis, fetal-derived tissues must first be obtained. All of the commonly used methods that yield fetal tissues are Invasive

Medical Genetics 2. Methods for obtaining fetal tissues for prenatal diagnosis To perform prenatal diagnosis, fetal-derived tissues must first be obtained. All of the commonly used methods that yield fetal tissues are invasive

Medical Genetics A Amniocentesis Amniocentesis is the withdrawal of amniotic fluid from the amniotic sac surrounding the fetus. for over two decades this has been the primary technique utilised for the diagnosis of fetal genetic disorders

Medical Genetics A. Amniocentesis Amniocentesis is the withdrawal of amniotic fluid from the amniotic sac surrounding the fetus. For over two decades this has been the primary technique utilised for the diagnosis of fetal genetic disorders

Medical Genetics Traditionally amniocentesis has been performed around 15 to 16 weeks gestation. At this time the uterus is easily accessible to a transabdominal approach, and a sufficient volume of amniotic fluid (approximately 200 ml) exists to permit 20 to 30 ml to be withdrawn safel

Medical Genetics Traditionally amniocentesis has been performed around 15 to 16 weeks gestation. At this time the uterus is easily accessible to a transabdominal approach, and a sufficient volume of amniotic fluid (approximately 200 ml) exists to permit 20 to 30 ml to be withdrawn safely

Medical Genetics Amniocentesis is normally performed as an outpatient facility An ultrasound examination is normally done immediately before the procedure to evaluate fetal number and viability perform fetal biometric measurements, establish lacental location and estimate amniotic fluid volume

Medical Genetics Amniocentesis is normally performed as an outpatient facility. An ultrasound examination is normally done immediately before the procedure to evaluate fetal number and viability, perform fetal biometric measurements, establish placental location, and estimate amniotic fluid volume