CHAPTER 4: CONGENITAL & CHROMOSOME DISORDERS

Question 1

Chromosomal Aberrations

Answer 1

structural: deletion, translocation, inversion

numeric: autosomes (downs), sex chr (turners or klinefelters)

Question 2

Cri du Chat

Answer 2

• deletion on chr 5
• high pitched cry

Question 3

Autosomal Aneuploidy

Answer 3

euploid: cells w multiple of normal # of chromosomes

aneuploid: abnormal # chromosomes, nondisjunction
(monosomy, polysomy)

Question 4

Trisomy 21: Down Syndrome
- what is it
- screening

Answer 4

extra copy on chr 21
- intellectual disability

prenatal screening
- HI up (human chorionic gondaotropin, inhibin A)
- dEFicit (estriol down, a-Fetoprotein down)

Question 5

Turner Syndrome

Answer 5

paternal nondisjunction of X chr
- broad chest, webbed neck, short stature

ALWAYS FEMALE (think tina TURNER)

Question 6

Klinefelter Syndrome

Answer 6

maternal/paternal nondisjunction of X chr
- testicular dysgenesis, feminization in men

in MALES (think calvin KLEIN)

Question 7

period of vulnerability

Answer 7

first 8 weeks of pregnancy

Question 8

Teratogenic Agents

Answer 8

• chem, physical, biologic agents cross placenta and cause abnormalities
• RADIATION: microcephaly, skeletal malformation, mental retardation
• DRUGS
• INFECTIOUS AGENTS

Question 9

Teratogenic Drugs

Answer 9

• thalidomide
• warfarin
• cocaine
• VITAMIN A

Question 10

Fetal Alcohol Syndrome

Answer 10

alcohol crosses placenta freely, result in CNS developmental delays and facial feature abnormalities

Question 11

Infectious Agents

Answer 11

ToRCHeS
- toxoplasmosis
- rubella
- cytomegalovirus
- herpes
- syhphilis

other: Varicella, TB, HIV

results: growth retardation, microcephaly, anemia, heart disorders

Question 12

Folic Acid Deficiency
- folic acid role
- risks
- effects

Answer 12

folic acid is key for DNA, RNA, RBC production

risks: excessive alc intake, malnutrition

effects: NEURAL TUBE DEFECTS
- anencephaly (open brain)
- spina bifida (neural tube doesn’t close properly, spinal cord defects)
- encephalocele (meninges and brain herniation)

Question 13

Prenatal Screening and Diagnosis

Answer 13

• ultrasonography
• maternal serum screening
• amniocentesis (test amniotic fluid)
• chorionic villus sampling
• percutaneous umbilical fetal blood sampling

Question 14

Ultra Sonography

Answer 14

• use for fetal anatomic imaging
• detect structural anomalies
  NONINVASIVE

Question 15

Maternal Serum Screening

Answer 15

identifies pregnancies at risk for fetal anomalies
- 1st trimester screening
- PAPP-A: dec in down syndrome
- hCG: inc in down syndrome
- Estriol: dec in down syndrome
- AFP: inc in defects (spina bifida, anencephaly)

Question 16

Prenatal Diagnosis: Amniocentesis

Answer 16

withdraw amniotic fluid from uterus

Question 17

Prenatal Diagnosis: Chorionic villus sampling

Answer 17

obtain tissue from chorionic villi (site of exchange of nutrients between maternal blood and embryo)