Quiz II Review

Question 1

What is this explaining? Given that someone has inherited the mutant allele, what is the chance that they will express the phenotype…

Answer 1

Penetrance

Question 2

What is this explaining? Given that a person who has inherited a mutant allele expresses the trait, how severely affected are they?

Answer 2

VE…Variable Expressivity

Question 3

What types of disorders exhibit ANTICIPATION?

Answer 3

Repeat Expansion Disorders

Question 4

What type of disorder shows increased severity and/or decreased age at onset in successive generations? What is the term used to describe this disorder?

Answer 4

Repeat Expansion Disorder….Anticipation

Question 5

What type of disorder reflects increased number of repeats as passed from generation to generation?

Answer 5

Repeat Expansion Disorders

Question 6

What is differential modification and expression of alleles of a gene depending on the sex of the parent of origin?

Answer 6

Imprinting

Question 7

What are the two main examples of IMPRINTING?

Answer 7

Prader-Willi=Father….Angelman=mother

Question 8

What are these TWO BIG clues related to? 1. Association of Uniparental Disomy (UPD) with abnormal development 2.Association of consistent parental origin of mutant allele in inherited disorder

Answer 8

Imprinting

Question 9

_______ allele usually refers to silent, inactivated allele

Answer 9

Imprinted

Question 10

What is the inheritance of 2 copies of a gene or chromosome from 1 parent?

Answer 10

Uniparental Disomy

Question 11

What mechanism has implications for recessive disorders and imprinted disorders in which it was first described in a child with cystic fibrosis; only the mother was a carrier? It si also very important for PWS and AS…

Answer 11

Uniparental Disomy

Question 12

Who do you receive your mitochondrial DNA from?

Answer 12

jo mamma!

Question 13

Does mitochondrial DNA have histones?

Answer 13

Nope

Question 14

What is the term used in mitochondrial genetics where you can have BOTH wild type AND mutant mitochondrial DNA?

Answer 14

HeteroPlasmy

Question 15

What is the term for the DOSE load of mutant DNA must meet a certain level before the phenotype is expressed?

Answer 15

Threshold effect

Question 16

Mutation Nomenclature: p.Gly17Arg

Answer 16

(p.=protein)….aa substitution, missense

Question 17

Mutation Nomenclature: p.Gly17*

Answer 17

stop codon, nonsense

Question 18

Mutation Nomenclature: p.Leu6Hisfs*3

Answer 18

frameshift mutation due to insertion or deletion of 1 or 2 nucleotides

Question 19

Mutation Nomenclature: c.101-2A>T

Answer 19

splicing mutation of intron

Question 20

What kind of mechanism is Achondroplasia? What happens with the Homozygous form?

Answer 20

Autosomal Dominant…its leathal

Question 21

What is the most common form of intellectual disability?

Answer 21

fragile X

Question 22

What happens when a PT testing for fragile X does not show ANY markers on PCR?

Answer 22

the patient has more then 100 repeats of the gene and is therefore going to need a SOUTHERN BLOT. the chances of the patient being affected by intellectual disability are very high.

Question 23

What are the two mechanism of inheritance in achondroplasia?

Answer 23

Autosomal Dominant or Incomplete Dominance

Question 24

In Achondroplasia, De Novo mutations are ALWAYS passed down by the ______. WHAT % are De Novo?

Answer 24

FATHER….NOT THE MOTHER…90% of Achondroplasia is caused by a De Novo mutation

Question 25

What are the 4 disorders associated with TriNucleotide Repeats??

Answer 25

1.Fragile X 2. Huntington Disease 3.Freidreich Ataxia 4.Myotonic Dystrophy

Question 26

What is the Nucletoide repeat for Fragile X? Where is it found?

Answer 26

CGG....found in the 5' UTR region

Question 27

What is the nucleotide repeat for Huntington's Disease? Where is it found?

Answer 27

CAG (polyGlu)....on the Exon

Question 28

What is the nucleotide repeat for Freidreich Ataxia? Where is it found?

Answer 28

GAA....intron

Question 29

What is the nucleotide repeat for Myotonic Dystrophy? Where is it found?

Answer 29

GTG...in the 3'UTR region

Question 30

What is the ONLY Autosomal Recessive disorder that is related to Trinucleotide repeats?

Answer 30

Fredreich Ataxia

Question 31

Which disorder has a trinucleotide repeat of CGG in the 5'UTR region?

Answer 31

Fragile X

Question 32

Which disorder has a trinucleotide repeat of CAG in the coding region?

Answer 32

Huntington's Disease

Question 33

Which disorder has a trinucleotide repeat of GAA in the intron?

Answer 33

Freidreich Ataxia

Question 34

Which disorder has a trinucleotide repeat of GTG in the 3' UTR region?

Answer 34

Myotonic Dystrophy

Question 35

T of F: A De Novo mutation can for Achondroplasia can be passed down by the mother.

Answer 35

FALSE. ITS ALWAYS THE FATHER.

Question 36

What 2 methods do we use to diagnose Achondroplasia?

Answer 36

1.PCR & 2.Restriction Enzyme Digestion

Question 37

What disease is associated with the most mutable nucleotide in the human genome?

Answer 37

Achondroplasia

Question 38

If a Pt showing signs of Fragile X has a PCR done and it does not read, they are more then 100 repeats. Are they intellectually disabled?

Answer 38

Not necessarily. 150 repeats is a mutant carrier...200 or more is phenotypic

Question 39

What will happen in a Fragile X MALE that is a mutant carrier, but is not intellectually disabled?

Answer 39

PD like symptoms with age

Question 40

What will happen in a Fragile X FEMALE that is a mutant carrier, but is not intellectually disabled?

Answer 40

Premature Ovarian Failure (early menopause)

Question 41

What are the three ways Uniparental Disomy can occur? Which is the most rare?

Answer 41

1.Trisomy Rescue 2.Monosomy Rescue 3.Gamete Complement...Gamete complement is the most rare...it requires non disjunction in BOTH male and female

Question 42

What chromosomes are the only viable autosomal trisomys?

Answer 42

13,18,21 only 21 is long term life

Question 43

What is the only viable monosomy?

Answer 43

45X (turner syndrome)

Question 44

What is the term for the mitochondrial DNA being transcribed in one big chunk?

Answer 44

Polycistronic

Question 45

What type of product is made with the dominant disorder haplodeficiency?

Answer 45

Normal Product, but HALF the amount...no phenotypic result