Genetics of Cardiac Disease Nov21 M1 Flashcards

1
Q

trisomy 21 malformations other than cardiac

A

anal, duodenal atresia

strabismus

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2
Q

trisomy 21 mental characteristics

A

intellectual disability, very happy and social

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3
Q

trisomy 21 % withcongenital abnormalities

A

40%

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4
Q

trisomy 21 3 frequent congenital CVD

A

atrial and ventricular septal defects
common atrioventricular canal
patent ductus arteriosus

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5
Q

free trisomy 21 def as opposed to other

A
free = 3 chrom 21
other = translocation
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6
Q

2 causes of trisomy 21

A

translocation

non disjunction at meiosis 1 or 2

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7
Q

deletion of 22q11: problems other than cardiac

A

hypoplasia of thyroid (hypoCa) or thymus (immune deficiency).
Malformations like cleft palate, kidney, etc.

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8
Q

% heart malformations in 22q11 deletion

A

75%

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9
Q

3 frequent congenital heart malform in 22q11 deletions

A

tetralogy of Fallot
ventricular septal defect
interrupted aortic arch

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10
Q

Tetralogy of Fallot: 4 anomalies

A

malalignement VSD
Subvalvular or valvular PS
RV hypertrophy
Overriding aorta

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11
Q

important consequence of hypoCa in 22q11 deletion

A

seizures

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12
Q

22q11 inheritance

A

autosomal dominant (dominant bc is a deletion in one of a parent’s chrom 22)

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13
Q

other name for 22q11

A

DiGeorge syndrome

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14
Q

how diagnose DiGeorge

A

karyotyping + dysmorphic features

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15
Q

cardiomyopathy from mt disorder: problems other than cardiac

A

hypoglycemia, high lactic acid, floppy baby, hearing loss

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16
Q

cardiomyopathy from mt disorder: cardiac problem

A

hypetrophy, heart murmur

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17
Q

general principle in mt disorder

A

expect to have 3 organs affected that aren’t connected

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18
Q

5 steps in mt disorder investigation

A
  1. general biochem workup
  2. eval other organs
  3. biochem genetic workup (plasma a.a, urine organic acids)
  4. biopsy (specific to mt eval)
  5. molecular testing (DNA panels and mtDNA)
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19
Q

medication in cardiomyopathy from mt disorder

A

carnitine, riboflavin, coenzyme Q10

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20
Q

problems making it important to follow in cardiomyopathy from mt disorder

A

special management during crisis, surgery, anesthesia. symptomatic treamtent. genetic counselling

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21
Q

mitochondria and mtDNa numbers

A

5-10 mtDNA per mt

0-2000 mt per cell

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22
Q

mt proteins # and origin

A
  1. more 90% from nucleus
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23
Q

mtDNA role

A

37 genes. tRNA, proteins, rRNA

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24
Q

RULES OF MTDNA GENETICS

A

Heteroplasmy
Mitotic segregation
Maternal inheritance

25
Q

heteroplasmy def

A

deleterious mutaitons in mtDNA affect some but not all mtDNA

26
Q

threshold effect in heteroplasmy

A

need minimal critical mutation load (80-90%) to get effect

27
Q

homoplasmic mtDNA mutation def

A

mutation in all the mtDNA

28
Q

why maternal inheritance in mt disorders

A

mitochondria in zygote come from mother

29
Q

cardiomyopathy bc of lysosomal storage disorder: cardiac prob

A

hypetrophy

30
Q

cardiomyopathy bc of lysosomal storage disorder: other than cardiac problems

A

acroparasthesias (tickling and numbness in extremities), proteinuria, cognitive delays, episodes of fever, abdo pain, kidney problem, corneal opacity, stroke, pain and fatigue, can’t sweat

31
Q

name of cardiomyopathy bc of lysosomal storage disorder

A

Fabry disease

32
Q

Fabry disease frequency

A

RARE. 1 in 200 000

33
Q

Fabry disease inheritance

A

X-linked (males more severely affected)

34
Q

Fabry disease cause

A

defect of enzyme alpha-galactosidase and accum of specific substrates

35
Q

Fabry disease: why important to know about

A

treatment easy: enzyme replacement therapy

36
Q

why have hypertrophy in Fabry disease

A

enzyme not cutting substrate (lysosomal storage disorder) and have accum of substrate

37
Q

Noonan syndrome: problems other than cardiac

A

dev delay, cognitive problems (mild), increased heart silouhette, hearing and vision problem

38
Q

cause of Noonan syndrome

A

genetic defect in any gene of growth factor receptor pathway + signal transduction to change gnee transcr (ERK, MEK, Grb2, KRAS, …)

39
Q

Noonan syndrome inheritance

A

autosomal dominant

40
Q

Noonan syndrome: cardiac defects (2)

A

hypetrophic cardiomyopathy, PS

41
Q

locus heterogeneity def

A

one situation can arise from mutaiton in diff loci (dif fgenes)

42
Q

locus heterogeneity saw in what (2)

A

Noonan syndrome

most of genetic cardiomyopathies

43
Q

3 type of cardiomyopathies (CM)

A

dilatative
hypertrophic
arrhythmogenic RV dysplasia (ARVD)

44
Q

dilatative CM # genes, role of proteins

A

30 genes. role in cardiac sarcomere, ion channels, dystrophin, etc.

45
Q

hypertrophic CM # assoc with what

A

assoc with syndromes

46
Q

hypertrophic CM non syndromic # genes

A

20

47
Q

ARVD CN # genes

A

7

48
Q

assessment of CM

A
  • clinical (Echo, ECG, MRI)
  • history + physical
  • cumul phenotype info
49
Q

Marfan syndrome systems involved

A

skeletal, cardiac, ocular

50
Q

cardiac prob in Marfan

A

dilatation, dissection of ascending or descending thoracic or abdominal aorta

51
Q

cause of Marfan

A

mutation in fibrillin 1

52
Q

Marfan inheritance

A

autosomal dominant

53
Q

Marfan genetic mechanism

A

dominant negative

54
Q

2 differentials of Marfan

A

Loeys-Dietz syndrome (aortic prob, more aggressive treatment)
Homocystinuria (diet restriction, meds)

55
Q

Marfan treatment

A

beta blockers, aortic surgery, no contact sport

56
Q

fibrillin function

A

glycoprotein part of cytoplasm structure linking complex with gene TGF factor

57
Q

prob with fibrillin mutation

A

neg effect on structure with TGF. gin of function. complex does diff function, pthway overstimulated

58
Q

3 types of genetic heart disease

A

heart malformation, hypertrophic CM, vascular disease

59
Q

5 genetic causes of genetic heart disease + particular one

A

abnormal # chrom (ONLY heart malformations), microdeletions, single gene mutation, mt disorder, lysosomal storage