Genetic Disease

Question 1

What is the transmission through gametes from parents?

Answer 1

Hereditary disorders

Question 2

What tends to occur more often in family members than is expected by chance alone?

Answer 2

Familial

Question 3

What is present at birth (not necessarily inherited)?

Answer 3

Congenital

Question 4

What is a group of symptoms which consistently occur together, or a condition characterized by a set of associated symptoms (inherited or not)?

Answer 4

Syndrome

Question 5

How is cytogenetic location by banding named?

Answer 5

1st: arm (p or q)
2nd: region (2 or 1)
3rd: band
4th: sub-band

Question 6

Would amplification or deletion make the chromosome longer?

Answer 6

amplification

Question 7

What is reciprocal translocation?

Answer 7

fragments are exchanged between 2 chromosomes (balances or unbalanced)

Question 8

What is Robersonian translocation?

Answer 8

translocation between Acrocentric chromosomes resulting in subsequent loss of “p” arms (unbalanced)

Question 9

What is isochromosome?

Answer 9

centromere divides horizontally rather than vertically

Question 10

What is a ring chromosome?

Answer 10

ends fuse and make circle

Question 11

What is loss of whole chromosome?

Answer 11

monosomy

Question 12

What is gain of whole chromosome?

Answer 12

trisomy (more common)

Question 13

What does 46, XX, t(2;5)(q31;p14) mean?

Answer 13

means balanced translocation between chromosome 2 and chromosome 5, with breaks in 2q31 and 5p14

Question 14

What is epigenetics?

Answer 14

changes in the regulation of gene expression that are NOT dependent on gene sequence
- heritable
- often caused by chemical modifications of DNA or chromosomal proteins (DNA methylation or histone modifications: acetylation, methylation, phosphorylation, etc)

Question 15

What is pleiotropy?

Answer 15

single gene mutation having many phenotypic effects

Question 16

What is genetic heterogeneity?

Answer 16

mutation at several different loci causing the same trait

Question 17

What is modifier genes?

Answer 17

affect severity of extent of phenotype caused by a mutation

Question 18

What are some features of triplet repeat mutations?

Answer 18

• anticipation: timing of onset of disease and severity relate to the number of repeats and therefor will become more severe from generation to generation
• penetrance: how many people show symptoms who have it
• expressivity: how severe it is
  penetrance and expressivity are both variable that relate to the number of triple repeats

Question 19

What type of disease does triplet repeat mutations cause?

Answer 19

neurodegeneration
- Huntington Disease
- Fragile X Syndrome

Question 20

What is Klinefelter syndrome?

Answer 20

• male with at least 2 X chromosomes and one or more Y chromosomes (47, XXY usually)
• decrease male traits
• decreased intellect

Question 21

What is Turner syndrome?

Answer 21

• phenotypic females with loss of one X chromosome (45, XO)
• decreased female secondary sex characteristics
• normal intellect