Pathologies Flashcards

Genetic disorders causes, genotype and phenotype

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1
Q

Non-disjunction has higher frequency in males or females?

A

Females

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2
Q

What is the consequence of mutation in the 3’ UTR?

A

Disturbed translation and localization

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3
Q

What are the genetic causes of Prader-Willi syndrome?

A
Paternal deletion (70%) - del(15q11-13)
Maternal UPD of chromosome 15 (28%)
Wrong imprinting (>2%)
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4
Q

A genetic defect can be expressed all over the body of a males while in females it will be expressed in some parts and some part it won’t. This is example of?

A

Chromosome inactivation

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5
Q

What are the causes for Down syndrome?

A

Almost always due to meiotic non-disjunction; small chance by Robertsonian translocation (centric fusion), mostly t(14;21)

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6
Q

Robertsonian translocation (centric fusion) can occur in which chromosomes?

A

13, 14, 15, 21 and 22 (acrocentric chromosomes)

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7
Q

Ring chromosome can occur in which chromosomes

A

Any chromosome

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8
Q

What are the symptoms of Turner syndrome?

A

Short stature, webbed neck, sexually undeveloped

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9
Q

What are the chances a kid will inherited an AR disease from his parents, if both are heterozygote healthy (carriers)?

A

25%

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10
Q

Marfan syndrome- name the inheritance mode, the defected gene and protein

A

Autosomal dominant, FBN1 gene and fibrillin protein

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11
Q

Fragile X syndrome- name the inheritance mode, the defected gene and the mutation

A

X-linked dominant, FMR1 gene and it is a triplet repeat disease (more than 200 triplets of CGG)

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12
Q

What are the symptoms of Angelman syndrome?

A

Developmental retardation
Compulsive movements
Inappropriate laughter (“happy puppet syndrome”)
Poor / incomplete speech ability

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13
Q

Name all the chromosome structural aberrations

A
Deletion (interstitial or terminal)
Duplication
Translocation (can be Robertsonian)
Insertion
Inversion
Ring chromosome
Isochromosome
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14
Q

Give an example of loss of imprinting (LOI) in a cancer

A

Loss of IGF2 imprinting in colon cancer (usually, only the maternal is expressed but in colon cancer the paternal is also expressed due to LOI)

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15
Q

What is the consequence of mutation in the polyadenylation site?

A

Decreased mRNA stability

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16
Q

What is the consequence of anaphase bridge?

A

Breakage of the chromosome, can be seen as acentric fragment (micronucleus)

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17
Q

How does red-green color blindness is inherited?

A

X-linked recessive

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18
Q

What is the consequence of exon mutation?

A

Changed amino acid or truncated protein (i.e., stop codon)

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19
Q

Huntington’s disease manifest earlier and more severely in successive generation. This is example of what?

A

Anticipation (a special type of variable expressivity)

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20
Q

Which 2 mutations occur in most of the cancers (60%)?

A

Ras (oncogene) and P53 (tumor suppressor) mutations

21
Q

Which gene is defected in achondroplasia?

A

FGF3 gene

22
Q

What are the chances a kid will inherited an AD disease from his parents, if one is heterozygote (sick) and the other is healthy?

A

50%

23
Q

Define in-frame mutation

A

Triplet nucleotide insertion or deletion that will keep the reading frame

24
Q

What is the reason for multipolar division?

A

Atypical duplication and division of the centrosome

25
Q

What are the genetic causes of Angelman syndrome?

A
Maternal deletion (70%) - del(15q11-13)
Paternal UPD of chromosome 15 (4%)
Wrong imprinting (~8%)
UBE3A mutation (~8%)
26
Q

Chimerism can occur due to?

A

Double fertilization
Dizygotic twins
Gene manipulation

27
Q

Define frame shift mutation

A

Insertion or deletion of nucleotide bases that change the reading frame

28
Q

What is the most common translocation in C-myc incase of Burkitt’s lymphoma? what are the others?

A

Reciprocal translocations- most common is t(8;14), others are t(2;8) and t(8;22)

29
Q

What is the consequence of intron mutation?

A

Errors in splicing or in regulation

30
Q

What is the inheritance pattern of adult PKD?

A

AD (remember- ADult is AD)

31
Q

Replications errors are higher in males or females?

A

Males

32
Q

Triplet repeat of CAG is the background of which disease?

A

Huntington’s disease

33
Q

Which gene is the most common defected in Waarndenburg syndrome?

A

Pax3 gene

34
Q

How many Barr bodies are in a Turner syndrome patient’s cell?

A

0 (there is no Barr body in Turner syndrome)

35
Q

What is the consequence of mutation in the 5’ UTR?

A

Decreased protein synthesis (translation)

36
Q

What is the mechanism of anaphase bridge?

A

Merotelic attachment of kinetochore microtubules- one chromatid is pulled from the two poles while the other chromatid is pulled only from one pole

37
Q

What is the reason fragile X syndrome is more common in males?

A

Reduced penetrance in females (although it is inherited in X-linked dominant pattern)

38
Q

Which protein is mutated in androgen insensitivity syndrome (AIS)?

A

Testosterone receptor

39
Q

A cystic fibrosis patient has a deletion of F508 in one chromosome and a point mutation in the other allele (of the homologue chromosome). This is example of what phenomenon?

A

Complex heterozygoty

40
Q

What will happen if mitosis is not followed by cytokinesis?

A

Multinuclear (giant) cell will be formed

41
Q

What is the mutation type in the background of Becker muscular dystrophy?

A

In-frame mutation (small deletion of trinucleotide repeat)

42
Q

What are the symptoms of Prader-Willi syndrome?

A

Obesity
Small hands and feet
Underdeveloped genitalia
Mild mental retardation

43
Q

What are the most important symptoms of Klinefelter syndrome?

A

Sexual immaturity (no sperm), breast swelling

44
Q

What is the inheritance pattern of infantile PKD?

A

AR

45
Q

What is the mutation type in the background of Duchenne muscular dystrophy?

A

Frame-shift mutation (large deletion)

46
Q

What is the consequence of mutation in the promotor region?

A

Altered transcription

47
Q

What are the symptoms of triploidy?

A

It is lethal (result in death; no symptoms)

48
Q

What is the result of mutation in sonic hedgehog gene (SHH)?

A

Cyclopia (rare form of holoprosencephaly), in which the eyes due not separate