Grody

Question 1

Amniocentesis

Answer 1

Invasive 
15th week (later than CVS)

Question 2

Chorionic Villus Sampling (CVS)

Answer 2

Invasive
10-12th week
Does NOT detect neural tube defects

Question 3

Fetal blood sampling (PUBS)

Answer 3

Invasive

used for sickle cell before but not just take sample of amniotic fluid

Question 4

Fetal tissue biopsy

Answer 4

Invasive

used for muscular dystrophy before but used to see mutations in amniocytes

Question 5

Which two sampling methods are not used anymore?

Answer 5

PUBS and fetal tissue biopsy

Question 6

Pre-implantation genetic diagnosis

Answer 6

Used in IVF
Grow to 8 cell stage, take one cell out and run PCR
If mutation throw it out
Only implant healthy embryos

Question 7

DMD genetics

Answer 7

Largest gene known

Deletions found in 2/3 of pts

Question 8

Multiplex PCR

Answer 8

Detects deletions

Used to test for DMD

Question 9

Cystic Fibrosis

Answer 9

Sx: abnormal secretions, chronic pulmonary disease
Screening: microarray of 16 mutations
Genetics: deltaF508 (deletion of phenylalanine at codon 508); autosomal recessive

Question 10

What do BRCA1 and 2 do normally?

Answer 10

help repair damaged DNA or destroy cells if DNA cannot be repaired

Question 11

How do BRCA1 and 2 increase risk for breast and ovarian cancer?

Answer 11

20% by age 40
50% by age 50
87% by age 70

Question 12

BRCA genetics and screening

Answer 12

Genetics: autosomal dominant
Screening: DNA screening gold standard

Question 13

Possible results of BRCA DNA screening?

Answer 13

Positive: proceed w/tx
No mutation: mutation previously identified or no known mutation
Identified mutation has uncertain clinical sig: further testing needed

Question 14

Why are southern blots used for tri-nucleotide repeat disorders?

Answer 14

Because the product is too big to show up on PCR

Question 15

Full mutation for Fragile X

Answer 15

200-1000 repeats

Question 16

Pre-mutation for Fragile X

Answer 16

52-200 repeats

Question 17

What are some late-onset sxs in male and female carriers of Fragile X?

Answer 17

Males: late onset tremor-ataxia-dementia syndrome
Females: premature ovarian failure

Question 18

What are some markers used in genetic testing?

Answer 18

Restriction fragment length polymorphisms (RFLP)
Variable number tandem repeats (VNTR)
Short tandem repeats (STR)
Single nucleotide polymorphisms (SNP)

Question 19

How is paternity testing done?

Answer 19

check SNPs on gel to see if match to mom or dad

Question 20

What are some DNA fingerprinting applications?

Answer 20

Paternity testing
Establishing zygosity of twins
Establishing identity of rapists
Bone marrow transplant determinant
Pedigree analysis of an animal

Question 21

What is free fetal DNA?

Answer 21

a new screening test that indicates if a woman is at increased risk of having a fetus w/Down syndrome
blood sample taken after 10 weeks of pregnancy