Ch. 6 Pedigree Analysis, Applications, and Genetic Testing

Question 1

pedigree

Answer 1

pictorial representation of a family history outlining the inheritance of one or more traits or diseases

Question 2

proband

Answer 2

a person having a trait or disease for whom a pedigree is constructed

Question 3

consanguinity

Answer 3

mating between related individuals

Question 4

genetic mosaic

Answer 4

condition in which regions of tissue within a single individual have different chromosome constitutions

Question 5

dizygotic twins

Answer 5

nonidentical twins that arise when two different eggs are fertilized by two different sperm

Question 6

monozygotic twins

Answer 6

twins that arise when a single egg fertilized by a single sperm splits into two separate embryos; also called identical twins

Question 7

concordance

Answer 7

percentage of twin pairs in which both twins have a particular trait

Question 8

genetic counseling

Answer 8

educational process that attempts to help patients and family members deal with all aspects of a genetic condition

Question 9

ultrasonography

Answer 9

procedure for visualizing a fetus in which high-frequency sound is beamed into the uterus; sound waves that encounter dense tissue bounce back and are transformed into a picture of the fetus

Question 10

amniocentesis

Answer 10

procedure used for prenatal genetic testing to obtain a sample of amniotic fluid from a pregnant woman. a long sterile needle is inserted through the abdominal wall into the amniotic sac to obtain the fluid

Question 11

chorionic villus sampling (CVS)

Answer 11

procedure used for prenatal genetic testing in which a sample piece of the chorion (the outer layer of the placenta) is removed from a pregnant woman. a catheter is inserted through the vagina and cervix into the uterus; suction is then applied to remove the sample

Question 12

karyotype

Answer 12

the complete set of chromosomes possessed by an organism; usually presented as a picture of a complete set of its metaphase chromosomes

Question 13

maternal blood screening test

Answer 13

method of screening for genetic conditions in a fetus by examining levels of certain substances in the blood of the mother. for example, the level of a-fetoprotein in maternal blood provides information about the probability that a fetus has a neural-tube defect

Question 14

noninvasive prenatal genetic diagnosis

Answer 14

genetic test performed on a fetus without taking a tissue sample from the fetus; usually performed by testing fetal DNA found within the maternal blood

Question 15

fetal cell sorting

Answer 15

separation of fetal cells from maternal blood. genetic testing on the fetal cells can provide information about genetic diseases and disorders in the fetus

Question 16

preimplantation genetic diagnosis (PGD)

Answer 16

genetic testing on an embryo produced by in vitro fertilization before implantation of the embryo in the uterus

Question 17

newborn screening

Answer 17

testing of newborn infants for certain genetic disorders

Question 18

presymptomatic genetic testing

Answer 18

testing to determine whether a person has inherited a disease-causing gene before the symptoms of the disease have appeared

Question 19

heterozygote screening

Answer 19

testing of members of a population to identify heterozygous carriers of a disease-causing allele who are healthy but have the potential to produce children who have the disease

Question 20

direct-to-consumer genetic test

Answer 20

test for genetic condition that can be purchased directly by a consumer without the involvement of a physician or other health-care provider

Question 21

Genetic Information Nondiscrimination Act (GINA)

Answer 21

U.S. law prohibiting health insurers from using genetic information to make decisions about health-insurance coverage and rates; prevents employers from using genetic information in employment decisions; also presents health insurers and employers from asking or requiring a person to take a genetic test