Exam 5 L1+2

Question 1

Dominant

Answer 1

effects observed in the presence of a normal allele - Heterozygous

Question 2

Recessive

Answer 2

effects observed in the absence of a normal allele -Homozygous

Question 3

Autosomal

Answer 3

Chromosomes 1-22

Question 4

Sex linked

Answer 4

X or Y chromosomes

Question 5

Autosomal Dominant

Answer 5

DD and Dd, Delayed onset, Huntington disease

Question 6

Autosomal Recessive

Answer 6

Dd and Dd, early onset, cystic fibrosis uniform

Question 7

Penetrance

Answer 7

Portion of people with mutated gene that show traits associated with it (population level)

Question 8

X linked recessive

Answer 8

Xx and Xy small x mutated, onlt males affected, hemophilia A and B, inversion,deletion,missense

Question 9

Expressivity

Answer 9

Complete to minimal, affected by other genes, harmful chemicals, environment, age

Question 10

Pathogenic variant

Answer 10

Responsible for causing disease, well supported by research, referred to as mutations

Question 11

Benign variant

Answer 11

Not responsible for causing disease
strong research to rule out link to disease

Question 12

Likely benign variant

Answer 12

Probably not responsible for disease, not enough research

Question 13

Uncertain significance variant

Answer 13

Not confirmed to cause disease, not enough research

Question 14

Likely pathogenic variant

Answer 14

Probably responsible for disease, not enough research

Question 15

Inherited variant

Answer 15

passed from parent to child, in every cell of the body

Question 16

Non inherited variants

Answer 16

occur sometime in person’s life
not in every cell
not passed on
can be caused by environment

Question 17

Somatic variants

Answer 17

non-inherited, occur in somatic cells (other cells than XY)

Question 18

New (de novo) variants

Answer 18

Not inherited, may occur in egg or sperm cell no other cells, in egg after sperm and egg unite
Variants during development can lead to mosaicism

Question 19

Silent mutation

Answer 19

no effect

Question 20

Missense mutation

Answer 20

Substitution, change amino acid, may produce malfunctioning protein

Question 21

Nonsense mutation

Answer 21

substitution, change amino acid to stop codon, causes shortening of protein

Question 22

Insertions and deletions

Answer 22

Switch out 1 or more amino acids
Results in frame shift, multiple of 3 does not shift

Question 23

Dominant negative

Answer 23

inhibits activity of unmutated protein

Question 24

Autosomal dominant caused by LOF disease

Answer 24

Familial hypercholesterolemia, mutations in LDL-R, 3000 pathogenic variants reported

Question 25

Osteogenesis imperfecta LOF dominant effect

Answer 25

Defects in collagen production, 2 subs alpha 1, 1 sub alpha 2

Question 26

Gain of function

Answer 26

PCSK9 binds to LDLR, instead of recycling, redirects to lysosome

Question 27

Cystic Fibrosis

Answer 27

Caused by LOF in CFTR, affects fluid secretion and epithelial lining of respiratory, gi, and reproductive tracts, fat malapsorption, bile duct blockage, fat malapsorption.

Question 28

Triplet repeat mutations

Answer 28

Longer repeats = disruption of gene function, 40 diseases, neurodegeneration associated

Question 29

Fragile x

Answer 29

Elongated face, protruding ears, low muscle tons, on Y chromosome

Question 30

FRM1 gene

Answer 30

on x chromosome, most common cause of familial mental retardation, methylation

Question 31

Translocation

Answer 31

transfer part of a chromosome to another

Question 32

Isochromosome

Answer 32

centromere divides horizontally instead of vertically

Question 33

Deletion

Answer 33

loss of a portion

Question 34

Inversion

Answer 34

two interstitial breaks the segment reunites but is flipped

Question 35

Ring chromosome

Answer 35

a variant of deletion after loss of segments from each end of the chromosome, the arms unite to form a ring

Question 36

Down syndrome

Answer 36

Trisomy 21, 3 copies instead of 2, from meiosis 1 nondisjunction, excess skin on back of neck, transverse palm crease, folded ear

Question 37

Turner syndrome

Answer 37

monosomy x, single x chromosome in females

Question 38

Mitochondrial mutations

Answer 38

Rare, only inherited from mother (dominant)
Males cant transmit to offspring
Mitochondria have a separate genome that encodes several enzymes involved in oxidative phosphorylation
Affected organs depend most on oxidative phosphorylation (skeletal muscle, heart, brain

Question 39

Cytogenetic disorders

Answer 39

Frequent 1/200 infants
Change in chromosome number or structure (autosomes or sex chromosomes)
Disorders from autosome number are more severe than single gene disorders

Question 40

Genetic imprinting

Answer 40

Some regions of DNA are turned off/inactivated when inherited from parents, occurs in ovum or sperm and is transmitted to all somativ cells

Question 41

Maternal imprinting

Answer 41

silencing of maternal allele

Question 42

Paternal imprinting

Answer 42

Transcriptional silencing of the paternal allele

Question 43

prader willi

Answer 43

chromosome 15 deletion from father

Question 44

angelman syndrome

Answer 44

chromosome 15 deletion from mother

Question 45

Are missense or inversion/deletions more rare?

Answer 45

missense