Ch 53 PowerPoint

Question 1

Chromosomes

Answer 1

Each cells holds genesAn error in number or structure of the chromosomes causes an abnormalityNormal cell has 46 chromosomes of two pairs of 23

Question 2

Aneuploid

Answer 2

A cell that has an abnormal number of whole chromosomesThere may to too may or too few

Question 3

Diploid

Answer 3

A cell having the normal pair of each chromosome. Normal cells are diploid, with the exception of the gametes

Question 4

Haploid

Answer 4

A cell having only one member of each pair of chromosomes

Question 5

Monosomy

Answer 5

A cell having only one of an individual chromosome

Question 6

Mosaic

Answer 6

A situation in which some cells have an abnormal number of chromosomes, while others do not

Question 7

Triploid

Answer 7

A cell having 3 times the normal haploid number

Question 8

Trisomy

Answer 8

A cell having three copies of an individual chromosome

Question 9

Anomalies

Answer 9

A structural feature that differs from the normEX: agenesis of the corpus callosum in which there is a congenital abscense of an important midline brain structure

Question 10

Syndrome

Answer 10

A group of clinically observable findings that exist together and allow for classificationThese signs and symptoms are linked to each other in some wayChromosomal abnormalities often exist when there are multiple defectsEx: Down Syndrome has clinically identifiable signs such as flat facial profile and a transverse crease in the palm of the hand

Question 11

Malformation

Answer 11

A structural abnormality that results from unusual developmentEX: Dandy-Walker malformation a congenital brain malformation that is thought to be caused by a developmental deviation in the roof of the fourth ventricle

Question 12

Triple screen

Answer 12

A maternal blood test in the second trimester for detection unusual levels of certain proteins or hormones with chromosomal Triple test has a 60% chance of detecting Down syndromeabnormalities

Question 13

Triple screen- Three lab Values

Answer 13

AFP, estriol, and hCGAFP- produced in the yolk sac and fetal liverEstriol and hCG are produced by the placenta

Question 14

Quadruple screen

Answer 14

The triple screen plus two proteins can be monitored which are produced by the placentaPAPP-A: pregnancy associated plasma protein ADimeric inhibin A

Question 15

Fetal Karyotyping and Genetic Testing

Answer 15

Advanced maternal age is considered to be 35 years of age or olderPatients with advanced maternal age have a greater risk of having an abnormal pregnancy of pregnancy failureFetal karyotyping is an analysis of fetal chromosomes and frequently recommended

Question 16

Three main procedures for obtaining material for fetal karyotyping

Answer 16

chorionic villi sampling, amniocentesis, cordocentesis

Question 17

Transvaginal chorionic villi sampling

Answer 17

Earliest procedure Small amount of chorionic villi is obtained for chromosomal testing Performed TA or TV 10-12 gestational weeks

Question 18

Transabdominal chorionic villi sampling

Answer 18

Under ultrasound guidance, a needle or plastic catheter is placed into the placental mass for the aspiration of trophoblastic cellsFetal loss rate is approx 0.8%

Question 19

Amniocentesis

Answer 19

Used for genetic purposes at around 15 weeksPerformed transabdominally with ultrasound guidancePhysician inserts a 20 to 22 gauge needle through the abdomen and into the anmiotic sac to remove amniotic fluid The most common side effects are uterine contractions and crampingRarely patients experience vaginal spotting, amniotic fluid leakage or amnionitisFetal loss rate 0.5%2-3 weeks for complete analysis of the fluid

Question 20

Cordocentesis

Answer 20

Also referred to as percutaneous umbilical cord sampling (PUBS)Performed TA at 17 weeksA needle is placed through the maternal abdomen and into the umbilical cord at its insertion point into the placentaA sample of fetal blood is removedFetal loss rate of 1% Allows for rapid detection of chromosomal anomalies, requires only 48-72 hours for analysis

Question 21

Down Syndrome (Trisomy 21)

Answer 21

Most common chromosomal abnormality
Occurs in 1 in 500 to 800 pregnancies
Fetuses have an extra chromosome 21

Question 22

Down Syndrome (Trisomy 21)- Maternal Serum Screening

Answer 22

Low AFP
Low Estriol
High hCG
High inhibin A
Low PAPP-A

Question 23

Down Syndrome (Trisomy 21)- Sonographic Findings

Answer 23

Absent nasal bones (hypoplastic nose)
Brachycephaly
Clinodactyly
Duodenal atresia
Echogenic intracardiac focus
Hyperechoic bowel
Macroglossia
Mild hydrocephalus
Nuchal thickening >/= 6mm between 16 and 20 weeks
Thickened nuchal translucency
Pericardial effusion
Pyelectasis
Sandal gap
Shortened limb
VSD’s
 Widened pelvic angles

Question 24

Edwards Syndrome (Trisomy 18)

Answer 24

Majority of fetuses die either before birth or shortly after birth
Fetuses have an extra 18 chromosome
All laboratory values are decreased

Question 25

Edwards Syndrome (Trisomy 18)- Maternal Serum Screening

Answer 25

Low AFP
Low estriol
Low hCG
Low inhibin A
Low PAPP-A

Question 26

Edwards Syndrome (Trisomy 18)- Sonographic Findings

Answer 26

Strawberry shaped skull
Agenesis of the corpus callosum
Choroid plexus cyst
Hypoplastic cerebellum
Enlarged cisterna magna
Micrognathia
Small, low-set ears
Esophageal atresia
Spina bifida
Clenched hands, overlapping index finger, fixed wrists
Cardiac defects
Omphalocele
Diaphragmatic hernia
Renal anomalies
Single umbilical artery
Feet abnormalities

Question 27

Patau Syndrome (Trisomy 13)

Answer 27

Holoprosencephaly and abnormal facies are common findings with Patau syndrome
Fetuses have an extra chromosome 13
Almost always a fatal condition, fetus typically dies in the neonatal period
Maternal serum screening not always beneficial in the diagnosis of this condition

Question 28

Patau Syndrome (Trisomy 13)- Maternal Serum Screening

Answer 28

Not always beneficial
Possible low AFP
Possible low inhibin A

Question 29

Patau Syndrome (Trisomy 13)- Sonographic Findings

Answer 29

Microcephaly 
Polydactyly 
Holoprosencephaly
Ventriculomegaly 
Agenesis of the corpus callosum
Small, low set ears
Facial anomalies(cyclopia, cleft lip, cleft palate)
Cardiac defects
Omphalocele 
Renal anomalies
Single umbilical artery 
Clubfeet

Question 30

Triploidy

Answer 30

Chromosomal abnormality in which the fetus has 69 chromosomes instead of the normal 46
Three sets of 23
Fetuses die in first or second trimester
Two types of triploidy, Type I and Type II
Often a partial molar pregnancy is found with a triploid fetus
Elevated hCG, bilateral ovarian theca lutein cysts

Question 31

Triploidy - 1st Trimester Sonographic Findings

Answer 31

Cystic spaces seen within an enlarged placenta(molar pregnancy)
Fetal demise
Bilateral ovarian theca lutein cysts

Question 32

Triploidy -2nd and 3rd trimester Sonographic Findings

Answer 32

Holoprosencephaly
Dandy-Walker malformation
Agenesis of the corpus callosum
Hydrocephalus
Facial abnormalites (microphtalmia and micrognathia
Small, low set ears
Cardiac defects
Renal anomalies
IUGR
Omphalocele
Single umbilical artery
Syndactyly (third and fourth fingers
Clubfeet

Question 33

Turner Syndrome

Answer 33

Disorder typically found in females
May also be referred to as monosomy X, as most often the paternal sex chromosome is missing
Classically presents with a nuchal cystic hygroma and nonimmune hydrops
Nonimmune hydrops is a buildup of fluid within at least two body cavities
Often fatal condition, spontaneous AB in first or second trimester

Question 34

Turner Syndrome- Maternal Serum Screening

Answer 34

Low AFP
Low hCG (with hydrops)
Low estriol
Low inhibin A(with hydrops)
Low PAPP-A

Question 35

Turner Syndrome- Sonographic Findings

Answer 35

Increased nuchal transluceny
Cystic hygroma
Renal anomalies (horseshoe kidneys and renal agenesis
Cardiac defects (coarctation of the aorta)
Nonimmune hydrops (ascites, pleural effusion, pericardial effusion, subcutaneous edema)