Exam 3- Genetic Disorders

Question 1

Pedigree Analysis

Answer 1

circle = female
square= male
colored= affected
——– = union

Question 2

What are the Genetic Disorder Study techniques?

Answer 2

• Amniocentesis
• Chorionic Virus Sampling

Question 3

How does Amniocentesis work?

Answer 3

• remove sample amniotic fluid ( fluid around the fetus)
• 15-18 weeks of pregnancy
• chromosome abnormalities; neural tube defects and genetic disorders
• 99% accuracy: CAN NOT tell the severity
• the risk of miscarriage

Question 4

How does Chorionic Virus Sampling work?

Answer 4

• remove cells from the placenta
• 10-13 weeks of pregnancy
• chromosomal abnormalities
• 98/99% accuracy
• the risk of miscarriage

Question 5

What are autosomal disorders?

Answer 5

gene mutation on autosomes
- autosomal dominant
- autosomal recessive

Question 6

Autosomal Dominant Disorders?

Answer 6

• an individual with AA has a disorder ( often lethal)
• Individuals that are heterozygote with Aa have the disorder
• aa does not have disorder

Question 7

Achondroplasia ( dwarfism)?

Answer 7

ex. of autosomal dominant disorder
- inability to convert cartilage to bone
- short, stocky limbs; normal trunk
- normal mental and sexual development

Question 8

Huntington Disease?

Answer 8

• neurological disorder
• progressive degeneration of brain cells
• severe muscle spasms
• personality disorder: loss of memory: depression
• irreversible, no cure
• death 10-15 years post symptomatic
• typical expression: 30-60 years of age
• 50- 50 chance of inhereting the disease from an affected parent

Question 9

What causes Huntington?

Answer 9

HD gene
- Huntington ( Htt) protein
- GAG repeat- glutamine

= nerve cells dying, function failure

Question 10

What are Autosomal Recessive Disorders?

Answer 10

• AA does NOT have the disorder
• Aa does NOT have the disorder
• aa DOES have the disorder
• Unaffected parents may have affected children

Question 11

What does the pedigree of a recessive disorder mean?

Answer 11

• Affected individuals with homozygous unaffected mates will have unaffected children
• close relatives who reproduce are more likely to have affected children
• Both males and females affected w. equal frequency

Question 12

Tay Sachs?

Answer 12

• Fatal progressive disease of the Central Nervous System
• lack of an enzyme called hexosaminidase A necessary for breaking down lipids in brain and nerve cells
• onset at 4-6 months
• death at 5
• rare

Question 13

What are some of the ways people spot tay-sachs?

Answer 13

• Baby stops smiling, crawling, and turning over, it loses the ability to grasp or reach out and eventually becomes blind paralyzed, and unaware of its surroundings.
• red spot on the retina; no treatment

Question 14

Cystic Fibrosis?

Answer 14

• most common genetic disorder among U.S whites
• mucus clogs the lungs and leads to life-threatening lung infections; chronic sinus infections
• mucus obstructs enzymes in the pancreas and in the absorption of food; poor growth
• infertility
• life span of 35 years

Question 15

What causes cystic Fibrosis?

Answer 15

• CFTR ( cystic fibrosis transmembrane conductive regulation)
• Abnormal Cl- and thiocyanate on transport