Genetic's #3

Question 1

What is Cri Du Chat (Cry of the cat)

Answer 1

• Heterozygous deletion of the tip of the short arm if chromosome 5
• Characteristic phenotype

Question 2

What are chromosomal duplications?

Answer 2

• An extra copy of a chromosome region

- Duplications supply additional genetic material capable of evolving new functions.

Question 3

What is Trisomy 21?

Answer 3

-Down syndrome
-an abnormal chromosome number
(47 not 46)

Question 4

What is turner syndrome?

Answer 4

-Absence of all or one part of the females X chromosome

Question 5

What are multifactorial disorders?

Answer 5

• Usually several genes involved and no clear inheritance pattern
• Often environmental contribution

Question 6

What is Teratogen?

Answer 6

-Environmental agent that produces abnormalities during embryonic or foetal development.

Question 7

What are teratogenic agents?

Answer 7

• Radiation
• Environmental chemicals and drugs
• infectious agents

Question 8

What is organogenesis?

Answer 8

Time interval of differentiation and organ development

Question 9

What are Epigenetic’s?

Answer 9

• Regulate activation and repression of genes.
• Changes in gene expression without changes in gene sequence
• Two main kinds =
  1. Methylation
  2. Histone modifications

Question 10

What is Prenatal tests (screening)?

Answer 10

• less invasive
• Give an estimate
• Not a “yes” or “no” answer

Question 11

What is a Maternal serum screen?

Answer 11

• Blood test, measures level of specific proteins produced by the foetus and placenta
• Maternal age+ proteins produce an estimated risk for chromosome abnormalities and neural tube defects

Question 12

What is Prenatal tests- Diagnostic?

Answer 12

• Give a clear answer
• Invasive
• Risk of miscarriage

Question 13

What is Amniocentesis?

Answer 13

• After 14 weeks
• Karyotype from a sample of amniotic fluid
• Identifies major chromosome anomalies
• Doesn’t identify gene mutations or chromosome changes.
• 99.5% accurate
• low risk for miscarriage

Question 14

What is Chorionic Villus Sampling?

Answer 14

• 10-12 weeks
• Karyotype analysis from a sample of the placenta
• Identified major chromosome anomalies
• Doesn’t identify gene mutations or chromosome changes
• 1/100 chance of miscarriage
• 96% accurate

Question 15

What are complex disorders (multifactorial) likely to involve?

Answer 15

• Both genetic and environmental factors

- Various modes of action