Patho-genetic screening (Exam 1, Fall 2022)

Patho-genetic screening (Exam 1, Fall 2022) Chromatin located in cells nucleus and contains chromosomes Chromosomes contain genes, basic units of inheritance Genes composed of DNA and histones that cause DNA to coil into tightly compressed structure Genetic testing helps to determine whether an individual carries specific disease-causing mutations Carrier screening identify heterozygous carriers for many recessive diseases -CF -Sickle cell -Tacy-Sachs helpful for reproductive decisions -especially in populations where diseases are common prevalence of some diseases have declined d/t increase in screening If the carrier is positive (usually mom) then the partner will undergo testing, even more complex testing Amniocentesis withdrawal of small amount of amniotic fluid from uterus @ 16 wks gestation fetal cells within fluid cultured and karyotypes to detect chromosome abnormalities low risk of fetal loss What can be detected as an elevation of alpha fetoprotein level in amniotic fluid? neural tube defects spina bifida anencephaly Chorionic villus sampling (CVS) extraving small amount of villous tissue (from placenta) from chorion @ 10-12 wks doesn't require in vitro cell culturing for chromosome analysis sufficient numbers directly available in tissue higher fetal loss than amniocentesis Preimplantation genetic diagnosis (PGD) carried out on early embryos (8-12 cells) created by in vitro fertilization 1-2 cells removed from embryo (