Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MFM ORAL BOARDS CWCW > Genetics Lecture > Flashcards

Genetics Lecture Flashcards

1
Q

inheritance of Huntington Disease

A

Autosomal Dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

inheritance of myotonic dystrophy

A

autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Trinucleotide repeat, what concept leads to expansion in the next generation

A

Anticipation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What trinucleotide expansion condition has higher risk if maternally inherited?

A

Mytonic dystrophy and fragile X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What trinucleotide expansion condition has higher risk expansion if paternally inherited?

A

Huntington

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Myotonic Dystrophy

A

AD
CTG repeat
DMPK gene
3’ end
Less than 37 normal
40-90 mild >50s
90-1000 moderate, 20s-30s
>1000s congenital
affected 80-2000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is most common form of inherited intellectual deficiency

A

Fragile X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Inheritance of Fragile X?

A

X linked dominant with reduced penetrance
(females can have it but a carrier MAY not have symptoms due to X inactivation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fragile X

A

CGG repeats (ribosomal protein)
mild phenotype females
FMR1 gene
premutation carriers- 50/50 chance of transmission expanding allele
MALE PREMUTATION CARRIERS WILL PASS PREMUTATION TO AL DAUGHTERS BUT LESS LIKELY TO EXPAND
AGG repeats- stability!
FULL MUTATION is >200

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

FXTAS

A

late onset progressive cerebellar ataxia, memory loss, cognitive decline, lower lim proximal muscle weakness.
PREMUTATION CARRIER FEMALES (age)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how many repeats will lead to full mutation of fragile X

A

> 200

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how many repeats will lead to full mutation of huntington disease

A

> 40 CAG
more repeats, younger age of onset
neurodegenerative disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If a dad wants to know if a child is at risk but does not want to know if he has gene change what do you do?

A

Exclusion testing (linkage analysis- way to look at different alleles)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do you test for trinucleotide expansion repeats?

A

PCR OR SOUTHERN BLOT FOR SIZE OF REPEAT
if too big, methylation testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what do you test for methylation testing for fetus?

A

Amniotic fluid
CANNOT do methylation testing on placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ddx for increased NT (>99th %tile or >3mm)

A

aneuploidy
CHD
Skeletal Dysplasia
Genetic Syndromes (NOONAN, SLO)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

NT > 3.5 with normal genetic testing and anatomy, what is likihood of normal baby?

A

95%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the most likely diagnosis with cystic hygroma

A

trisomy 21

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

quad screen analytes

A

afp, hcg, inhibin, estriol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what serum screening results with T21

A

“HI!”
HIGH HCG AND INHIBIN
LOW ESTRIOL AND AFP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

WHAT SERUM screening results for T18?

A

ALL LOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is associated with extremely low estriol?

A

x linked ichythiosis
SLO

23
Q

what can cause a low fetal fraction?

A

obesity
aneuploidy
Mosaicism
drawn too early
maternal condition (autoimmune)
medication exposure (lovenox)

24
Q

what can cause false positive CFDNA results?

A

maternal malignancy
demise of co twin
maternal karyotype abnormality
placental mosaicism

25
Q

inheritance of spinal muscular atrophy?

A

autosomal recessive

26
Q

what is a silent carrier for SMA?

A

2 normal copies of SMN on 1 allele
then partner status must be determined

27
Q

how do we screen for hemoglobinopathies?

A

all patients should have a CBC, Hb electrophoresis OR molecular genetic testing if concerned

28
Q

most likely tested ashkenazi jewish conditions (ACOG)

A

CF, Tay Sachs, Canavans disease, familial dysautonomia

29
Q

heteroplasmy vs variable expressivity

A

specific for mitochondrial conditions

30
Q

risk of loss from CVS?

A

1 in 300

31
Q

mosaics with wHAT chromosomes do you have to worry about uniparental disomy/trisomy rescue?

A

6,7,11,14,15

(lets say you do CVS and get mosaic trisomy 14. Follow up Amnio is normal. CONSIDER METHYLATION STUDIES TO RULE OUT UPD)

32
Q

SIZE OF DEFECT TO SEE ON KARYOTYPE?

A

4-5 MB

33
Q

WHAT IS CYTOGENETICS

A

STUDY OF STRUCTURE OF CHROM AND THEIR INHERITANCE- NEED LIVE RAPIDLY DIVIDING CELLS (AMINOCYTES!)

34
Q

what is the most common mechanism for aneuploidy?

A

nondisjunction in meiosis I

35
Q

benefit of karyotype over microarray?

A

both detect large aberrations
Karyotype alone can see balanced translocations

36
Q

what are some limitations of chromosomal microarray

A

cannot detect truly balanced translocations, does not detect all cases of mosaicism, no point mutations or intragenic mutations, risk of CNV uncertain significance

37
Q

microarray result with abnormality (such as VUS) what is the next step?

A

test the parents

38
Q

Spina bifida

A

bony defect with neural content/exposure. 99% have chiari II (banana sign, cerebellum protruding into foramen magnum)
lemon sign- scalloping of frontal bones

39
Q

Dddx of etiology of neural tube defect

A

mostly sporadic
rare cases trisomy 13 or 18

40
Q

what are clinical considerations of NTD?

A

Possibility of in utero vs postnatal repair- MOMS TRIAL
route of delivery (Vaginal versus CD)
Folic acid supplementation
prognosis (worse if higher)
1-2% recurrence
seizures, shunt, bladder/bowel dysfunction, walking
TOP

41
Q

MOMS TRIAL inclusion criteria

A

GA 19-25w6d
Normal karyotype
S1 lesion or higher
confirmed chiari II on US and MRI

42
Q

MOMS trial exclusion

A

obesity
T2DM
history of PTD
uterine anomaly

43
Q

Risks/benefits of in utero repair NTD

A
44
Q

Embryological development of anencephaly

A

failure of neuropore to close anteriorally

45
Q

embryological development of spina bifida

A

failure of neuropore to close posteriorally

46
Q

ddx for anencephaly

A

no calvarium with absence of neural tissue above orbits
ddx: anencephaly, amniotic band syndrome, severe microcephaly, encephalocele, atelecephaly (small fluid-filled calviarum without intracranial structrures)
LETHAL

47
Q

risk factors for neural tube defect

A

folic acid deficiency, obesity, methotrexate, valproic acid, carbamezapine (folic acid antagonists)

48
Q

nexty pregnancy management of NTD

A

supplement Folic acid 4 mg
decreases recurrence by 70%

49
Q

alobar holoprosencephaly genetics?

A

25-50% trisomy 13
SLO, Meckel Gruber,
aicardi/fryns, velocardofacial syndrome

50
Q

ALOBAR VERSUS LOBAR VERSUS SEMILOBAR

A

ALOBAR fused thalami with monoventricle
LOBAR absent CSP, fused fornices, thalami separate
SEMILOBAR - fused frontal lobes, thalami partially fused

51
Q

what is a sacrococcygeal teratoma?

A

mass coming off sacrum, neoplasm derived from all 3 cell layers, mixed cystic/solid, color doppler for vascularity

52
Q

what genetic syndromes have Cleft lip/palate

A

trisomy 13
trisomy 18
treacher collins
22q11.2 deletion

53
Q

classic meckel gruber triad

A

renal cystic dysplasia
encephalocele
post axial polydactyly

MFM ORAL BOARDS CWCW (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions