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Final Review GC > Cram 6 > Flashcards

Cram 6 Flashcards

1
Q

mtDNA - size, number of genes?

A

16.5kb, 37 genes

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2
Q

which genetic conditions cancause oligospermia?

A

5% of menwith oligospermia have a karyotype abnormality. -unbalanced translocations are more commoninmenw oligospermia -47,xxy - non-obstructive oligo or a zoo

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3
Q

fasting plasma ammonia levels innormal, UCD, transient hyperammonemia of new born

A

normal - 15-35uM THAN - 4,750uM CPS - 1,000uM OTC - 1,100uM AS - 892 AL - 807 use citrulline and arginine to differentiate: citrulline -CPS &OTC - no/v. low citrulline -AS - vs. high (2656) citulline -AL - high citrulline (176) -THAN -
s l i g h t l y h i g h ( 5 4 ) v s . nl 6 - 2 0 a r g i ni ne : - C P S , O T C , A S , A L - l o w - T H A N - no r ma l ( 3 0 - 84)

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4
Q

risk forabnormal outcome in1st cousinmating?

A

3-5%, double the overall background risk of 2-3% (forstillbirth, neonatal death, c o ng e ni t a l ma l f o r ma t i o ns ) - i nc r e a s e d r i s k f o r 3 r d c o u s i ns o r mo r e d i s t a nt l y r e l a t e d is negligible (T&T)

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5
Q

L e i g h s y nd r o me , N A R P L e i g h - ma ny mi t o c h o nd r i a l g e ne s N A R P - M T - A T P 6 o nl y gene

A

Leigh and NARP (neurogenic uscle weakness, ataxia, RP) are part of a continuum of progressive neurodegenerative disorders -Leigh: –onset 3-12mo, oftenafter viral infection–decompensation(w lactic acidosis) inincurrent illness - ass’d w p s y c h o mo t o r e t a r d a t i o n o r r e g r e s s i o n - h y p o t o ni a , s p a s t i c i t y , mo v e me nt d i s o r d e r s (chorea), cerbel l ar ataxi a, peri pheral neuropathy, crani al nerve abnormal i ti es) – HCM –75%dieby2-3yo(usualyrespiratoryorcardiacfailure)-NARP –proximal neurogeni c muscl e weakness w sensory neuropathy, ataxi a, pi gmentary reti onopathy

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6
Q

relationshipbetweenmutationrateand fitnessforcalculations?

A

Mutationrate=sq(allelefrequency)=(1-f)(allelefrequency)

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7
Q

calculationof mtnrate fromfitness of x-linked recessive

A

SelectionAgainst X-Linked Recessive Mutations – If anX-linked phenotype is
benignand if affected males have normal fetuses, 1/3 of mutant alleles are in males and 2/3 are infemales. Whenselective disadvantage against males occurs, μ = s * q/3 Whens = 1, 1/3 of all copies a mutant gene are lost ineach generation and the disease is a genetic lethal condition.

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8
Q

biochemical lab finding ass’d with Lesch-Nyhansyndrome?

A

hi gh uri c aci d

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9
Q

biochemical lab finding ass’d with acute itnermittent porphyria?

A

high delta-aminolevulinic acid

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10
Q

biochemical lab finding ass’d with x-linked ardrenoleukodystrophy?

A

h i g h v e r y l o ng c h a i n f a t t y a c i d s

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11
Q

galactosemia

A

-jaundice,abnormal liverfunctiontests(LFTs),hyperbilirubinemia-bleeding diatheses, burising, coagulopathy -feeding problems -irritability, lethargy - sepsis** -cataracts** -elevated amino acids -hypoglycemia -renal fanconi syndrome -long term: —DD, esp. expressive language delay (‘verbal dyspraxia’) —motor delays (ataxia, tremor) —POF, hypergonadotropic hypogonadism, low bone density - t x : s t o p b r e a s t f e e d i ng , d a i r y ; s o y f e e d s ; c o ns d i e r s e p t i c r i s k ; t r e a t l i v e r d i s e a s e and jaundice

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12
Q

at what week inthe pregnancy to physiologic omphaloceles resolve by?

A

1 5 w e e k s . i f s e e n p r i o r t o t h a t a n o mp h a l o c e l e ma y b e c o mp l e t e l y no r ma l a nd doesn’t warrant further testing.

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13
Q

ismaternal diabetesass’d withanincreased risk forNTD?

A

yes

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14
Q

MSAFP at 2.5MoM detectionrate foropenneural tube defects?

A

80%

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15
Q

what percentage of balanced translocations are inherited?

A

70% (online review course)

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16
Q

what phenotype is seenwith 46,XY,del(9)(p24) ?

A

sex reversal

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17
Q

Which of the following parental karyotypes is associated with the lowest risk for having a livebornchild with a chromosome abnormality?a) 45,XX,der(13;14) (q10;q10) b) 46,XX,t(11;22)(q23.3;q11.2) c) 45,XX,der(14;21)(q10;q10) d) 46,XX,del (22)(q11.2;q11.2) e) 47,XX,+21

A

a) 45,XX,der(13;14)(q10;q10) –1% b) 46,XX,t(11;22)(q23.3;q11.2) –6% c) 45,XX,der(14;21)(q10;q10) – 12% d) 46,XX,del (22)(q11.2;q11.2) – 50% e) 47,XX,+21 – 50%

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18
Q

ASAFP + ultrasound -detectionratesforNTD and anencephaly?

A
  • N T D - 9 8 - 9 9 % - a ne nc e a p h a l y - v i r t u a l l y a l l
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19
Q

reasonsforelevated AFAFP

A

NTD -underestimated gestational age -fetal death -twins -blood contamination -abdominal wall defects (omphalocele, gastroschesis)

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20
Q

whenis acetylcholinesterase present (AChE)?

A

withinopenNTD only(not closed, not abdominal wall defect)

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21
Q

what is the recommended dosage of folic acid -general population?-previous child withNTD?

A

-genpop: 0.4 mg/day -previous child: 4mg/day

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22
Q

CVS details

A

10-12 wks 6 days -0.5-1.5% mi scarri age ri sk (some studi es say comparabl e to amnio) -biochemical testing possible (onchorionic vili, not onamniocytes, ex. c o l l a g e n s t u d i e s f o r O I ) - C V S < 1 0 w e e k s - i nc r e a s e d r i s k t r a ns v e r s e l i mb abnormality

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23
Q

PUBS details

A

> 16 weeks -1-3% fetal loss rate -rapid karyotyping (48 hrs, tho less of an
advantagewithinterphaseFISH onamnioorcvs)-indications:mgmt of Rh compatibility, featal blood profile forgenetic conditons, detectionof infection, diagnosis of hemoglobinopathies, confirmationof CVS/amnio results

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24
Q

2nd tri screening - time window?

A

15 - 20 weeks

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25
Q

which markers have the strongest ass’nwith downsyndrome?

A

h C G a nd I nh i b i n A

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26
Q

MSAFP cutoff and detectionrates

A

2 . 5 M o M - 9 0 % o f a ne nc e p h a l y - 8 0 % o f N T D

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27
Q

when do you repeat MSAFP?

A

if it’s2-3MoM (depends on the center)

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28
Q

FISH resolution

A

1-100 kb

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29
Q

uE3associations

A

low indownsyndrome -low intrisomy 18 -very low (0-0.15 MoM) with: —-x-
l i nked i chthyi osi s (scal i ng ski n, corneal opaci ti es, hyperkeratosi s) —-SLOS (MR, mi c r o c e p h a l y , 2 - 3 t o e s y nd a c t y l y , ma l e s w h y p o g o na d i s m o r a mb i g u o u s g e ni t a l i a ) - —CAH —-maternal anti bi oti c or corti costeroi d therapy —anencaphl y

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30
Q

PWS - lacking ____ contribution of _____.

A

paternal, 15q11-13

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31
Q

Angel man- lacking _______ contribution of _________.

A

maternal, 15q11-13

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32
Q

timewindowforfirst trimesterscreen?

A

10-14 weeks

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33
Q

PWS etiology by frequency

A

pat 15q11-13 del (70%) mat UPD (30%) impriting center defect (5%) unknown

(<1%) single-gene mutation

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34
Q

Angelman etiology by frequency

A

mat 15q11-13 del (70%) single gene mutation- UBE3 (10%) pat UPD (3-5%)

unknowncase (10-15%)

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35
Q

AR diseases with de novo mutations

A

SMA 21-hydroxyl ase deficiency

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36
Q

NT>3mmass’d with?

A

tri 21, 18, 13-turner-triploidy-CHD -diaphragmatic hernia -skeletal dysplasiaarthrogryposis-noonansyndrome– if karyotypenormal offerdetailsultrasound and fetal echo

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37
Q

HD repeat ranges

A

<35 normal 35-39 intermediate <40 affected (T&T) <26 normal 27-35 intermediate,
mutable 36+ abnormal 36-39 - incomplete penetrance 40-60 HD, 100% penetrant

> 60 juvenile HD

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38
Q

HD repeat: _ _ _ in the ___ region of the gene

A

CAG incoding regi on(i .e. polyglutamine disorder)

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39
Q

what maternal serumanalyte patterns are ass’d with increased risks of IUGR, fetal demise, preeclampsia, placental dysfunction?

A

high AFP -high hCG (>2-3 MoM) -high Inhibin(>2-2.5 MoM) -low PAPP-A (<0.35-38 MoM)

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40
Q

Fragile X repeat ranges

A

<50 normal 50-58 intermediate 59-200 premutatoin 100-200 premutation with
100% of expanding to full mtninoogenesis >200 affected, hypermethylated

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41
Q

Fragile X repeat: _ _ _ in the _____ region of the gene.

A

CGG in the 5’ UTR

42
Q

integrated vs sequential screening?

A

falsepositiverateishigherinsequential (9%vs.5%),detectionratesaresimilar c o nt i ng e nt a c h i e v e s a d e t e c t i o n a nd F P R s i mi l a r t o i nt e g r a t e d , b u t f e w w o me n come back forthe second draw

43
Q

Myotonic dystrophy repeat ranges

A

<30 normal 50-80 may be mildly affected 80-2000 affected

44
Q

twin pregnancy screening detection rates?

A

NT 75% with 7% false positive -integrated screening 45% with 5% false positive

45
Q

Myotonic dystrophy: _ _ _ in the ________ region of the gene

A

CTG in the 3’ UTR

46
Q

interpretationof serumscreening results GA: 15 weeks Maternal weight: 132 lbs Race: CaucasianIDDM: No Multiple gestation: No Maternal age at EDD: 34 yo AFP MoM: 4.75 uE3 MoM: 1.47 hCG MoM: 2.64

A

increased risk forNTD (b/c highAFP)increased risk forobstetric complications - IUGR, fetal demise, preeclampsia (b/c high AFP)

47
Q

Friedreich ataxia repeat ranges

A

<34 normal 36-100 intermediate >100 affected

48
Q

Friedreich ataxi a repeat: _ _ _ in the ______ region.

A

AAG in an intron

49
Q

ultrasound sensitivityfordefects-ventral wall defects-urinarytract -NTD - c a r d i a c d e f e c t s - c l e f t l i p / p a l a t e - mi c r o e p h a l y - l i mb s

A

ventral wall defects - 92% -urinary tract - 91% -NTD - 80-90% -cardiac defects - 1 3 - 3 5 % ( 6 7 % i n t a r g e t e d 2 nd t r i u / s ) - c l e f t l i p / p a l a t e - 3 0 % - mi c r o e p h a l y - 27% - l i mb s - 25%

50
Q

example of pseudoautosomal inheritance

A

dyschondrosteosis mutations i nSHOX or SHOXY (al so cause short stature) or
del eti ons in pseudoautosomal region Y pter-p11.2, Xpter-p22.32

51
Q

what region of the X chromosome is critical for ovarian function?

A

xq13-q26

52
Q

downsyndrome soft markers onultrasoudn?which has the biggest effect size/RR?

A 
NT thickening (1st tri) -nuchal thickening (2nd tri) - biggest effect size/RR - cardiac defects -intracardiac echogenic focus -CPC (more ass'd w tri 18) -
e c h o g e ni c b o w e l - s h o r t e ne d f e mu r a nd h u me r u s - d u d e na l a t r e s i a - p y e l e c t a s i s - 5 t h fingerclinodactyly
53
Q

cleft lip+/- palate-ethnicityass’n?-ass’nwithothercongenital defects?- r e c u r r e nc e r i s k f o r s i b , c h i l d ?

A

nativeamericans>asians>caucasians>hispanics>africanamericans-cleft lip- 7 - 1 3 % a s s ‘ d w i t h o t h e r a no ma l i e s - c l e f t l i p w p a l a t e - 1 1 - 1 4 % a s s ‘ d w i t h o t h e r anomal i es -si b recur. ri sk 3-7% -chi l d recur ri sk 2-4%

54
Q

mutation rate

A

• mutation rate: • varies with disorder, gene, size of gene, mutability of gene • avg:
10-6/locus/generati on• high rates: achon1.4x10-5, DMD 3.5x10-5 • 10-
6/locus/generation x 25,000 genes = 2.6% risk of new mutation at one
locus/generation, i .e. 1/40 ppl received a new mutation

55
Q

s y nd r o me s a s s ‘ d w i t h c l e f t l i p / p a l a t e

A

pierrerobinsequence(CP)-22q del (CP)-stickler(CP)-treachercollins(CP)-vand e r w o r u d e ( C L + / - C P , o r C P ) - t r i s o my 1 3 / 1 8 ( C L + / - C P ) - a p e r t / c r o u z o n ( C P ) -
waardenburg (CP or CL)

56
Q

XLR lethal numbers for bayes

A

chance any woman is a carrier 4u chance mother of isolated male case is a carrier
2/3 chance mat’l GM of isolated male case i s a carrier 1/3

57
Q

definitions of -coeff’t of relationship (R) -coeff’t of inbreeding (F ) -probability
child born to consanguineous parents will have an AR disorder

A

• Coeff of Relationship ( R) = proportion of shared genes between two people =
1/2^degree of r’ship • Coeff of inbreeding for this couple’s child (F ) = R/2; F i s
the likelihood of the child being homozygous at any one locus, because of
decent; it is al so the proportion of loci that are identical by decent. • The
probability that a child born to consanguineous parents wi l l have anAR disorder =
F /2 (this assumes that everyone carries 1 AR disorder (Young, Ch. 3))

58
Q

what is cystic hygroma ass’d with?

A

t u r ne r - t r i s o mi e s - t r i p l o i d y - no o na n - F A S “ a n a r e a o f s o no l u c e nc y i n t e h s o f t t i s s u e of theposterioraspectsof theneck,consistingof 2symmetrical cavities compl etel y separated by a mi dl i ne septum”

59
Q

congenital toxoplasmosis

A

chorioretinitis (most commonfinding - eye infection) -pneumonia -anemia - jaundice -nephritis -rash long term: MR, seizures, spasticity, deafnes, blindness tosoplasosis gondii is a parasite found inundercooked meat, cat feces, soil - p r e v e nt i o n i s k e y , t x w a nt i o b i o t i c s d e c r e a s e s s e v e r i t y b u t d o e s n’ t d e c r e a s e transmi ssi on

60
Q

which mitochondrial diseases are homoplasmic?

A

deafness induced by aminoglycoside antibiotics, caused by 12S rRNA mutations
(1555A>G, 7335A>G) LHON caused by ND4 and ND1 mutations (electron transport chain)

61
Q

CMV

A

congenital CMV: hepatosplenomegaly, chorioretinitis, optic atrophy,
mi c r o c e p h a l y , h e a r i ng l o s s , M R - a nt i b o d y s c r e e ni ng , a mni o . P U B S a s s c r e e ni ng tools -only 5% have abnormal ultrasound (IUGR, echogenic bowel, intracranial calcification, ventriculomegaly)

62
Q

which mitochondrial diseases are caused by the same mutation?

A 
MELAS, CPEO (chronic progressive external ophthalmoplegia) are both caused by
tRNAl eu(uur) 3242A>G CPEO and KSS are both caused by the ~5kb large KSS

deletion, which i s usually sporadic

63
Q

maternal diabetes and birth defects

A

in6-10% of poorly controlled patients, up to 20% of very poorly controlled -NTD -heart defects -skeletal defects -defects inurinary, reproductive, digestive systems -increased risk of breathing difficulties, hypoglycemia, jaundice

64
Q

teratogens- radiation

A

CNS defects, MR, microcephaly, growth retardation>5 rads

65
Q

which mitochondrial diseases are usually sporadic, caused by somatic mutation?

A

Kearns-Sayre syndrome (KSS, ~5kb deletion) CPEO (chronic progressive external
ophthalmogplegia) due to the KSS del Pearson syndrome, due to large deletions

66
Q

HB Kempsey

A

GoF mutation locks HB in high oxygen affinity state, thus reducing oxygen delivery

to tissues

67
Q

c a r r i e r s c r e e ni ng f o r s p e h a r d i c j e w is h population - mediteranean

A

-beta thal -familial mediteraneanfever-glucose-6-phosphate dehydrogenase deficiency -glycogenstorage disease type III

68
Q

Beta-thal trait – which ethnicities i s it prevalent in and what’s the carrier rate?

A

Mediteranean- 1/20-1/30 Hi spani c - 1/30-1/50 SE asi an- 1/30 Asi an
subcontinent (i ndi a, paki stan) - 1/30 (fromACMG)

69
Q

which asiancountries do not have anincreased frequency of hemoglopinopathies?

A

Japan and Korea

70
Q

alpha-thal trait - which ethnicities? what carrier rate? cis or trans?

A

mediteranean 1/30-1/50 trans african-american1/30 trans carribean, west indean
1/30 trans west afri can1/30 trans asi an1/20 ci s SE asi an>1/20 ci s

71
Q

sickle cel l - which ethnicities? carrier frequencies?

A

african-american1/12 caribbean, west indean1/12 west african1/6

72
Q

Hb C - which ethnicities? what carrier rate?

A

african-amerian 1/50 caribbean, west indian- 1/30 west african1/20-1/30

73
Q

what is the time frame for amnio?

A

beginning of 15th week to end of pregnancy

74
Q

w h a t A R c o nd i t i o ns a r e i nc r e a s e d i n i nd i v d i u a l s o f c h i ne s e a nc e s t r y ( f o r c a r r i e r screeni ng)?

A

betathal –3%(1/33)alphathal cis–1/20southernchina-hemoglobine

75
Q

what is the time frame for CVS?

A

10-12 weeks and 6 days

76
Q

howtotest inTay-Sachscarrierscreening?

A

NSGCpublicationrecommendsbiochemical notmoleculartestingb/c”simple,
i nexpensi ve, and hi ghl y accurate” -hexomi ndase a and total hoxosami ni dase measured inserum– males, non-pregnant females -leukocyte hexosaminidase for pregnnat women, womentaking OCP, anyone whose seumassy is incocnlusive - performmolecularanalysiswhenenzymeanalysisisabnormal toruleout presence of pseudodeficiency allele (35% of non-AJ heterozygotes are actually carriers of a pseudodeficiency allele)

77
Q

what carrierscreeningshould beoffered toindividualsof frenchcanadianor cajunancestry?

A

taysachsbyenzymestudies-CF panel

78
Q

what weeks of development are most susceptible to teratogens? i .e. teratogenic

exposure most likely to cause birth defects?

A

week 3-8, during organogenesis. before week 3 any damage done would likely be

lethal after week 8, fetus is growing

79
Q

prenatal diagnosisforTay-Sachs?

A

enzymeanalysisoneitherCVSoramniosample-moleculartestingif mutationis knowninboth parents

80
Q

which birth defects are more common in males than females?

A

most! pyloric stenosi s (4.43:1) hirschsprung disease (2.79:1) clubfoot (1.43:1)
cleft lip with/without palate (1.41:1) polydactyly syndactyly cranyosynostosis

congenital diphragmatic herni a

81
Q

Hispanics- what conditionsforcarrierscreening?

A

incidence of hemoglobinopathies varies a lot withinHispanic populations dependent onAfrican-originadmixture-Carribeanancestryishighest:1/9forHb S , 1 / 3 0 f o r H b C - o f f e r s c r e e ni ng - me x i c o - l o w ( h i g h e s t i s H b S a t 1 / 6 7 - 1 / 1 0 4 ) - s c r e e ni ng p r o b a b l y no t i nd i c a t e d

82
Q

which birth defects are more common in female than males?

A

most are more common in males than females. male:female ratio: anencephaly
(0.48:1) holoprosencephaly (0.5:1) spina bifida (0.77:1) microcephaly (0.67:1)
congenital dislocation of hi p (0.33:1) absence of ribs

83
Q

Significance of poly T and TG tracts in CFTR.

A

poly T in intron8: 7T and 9T are normal , 5T i s a vari abl y penetrant mutation poly
TG tract i s 5’ to pol y T tract longer TG (13) &shorter T (5) - more probl ems with
intron8 splicing 5T al one - can be assocaited with CBAVD R117H + 5T (ci s) - CF
mutation 5T incombination(ci s) with 13TG - greater impacton intron8 splicing
(ex. deltaF508 with 5T/13TG - could develop non-classic CF or CBAVD) only test

T: 1) as reflux in carrier testing i f R117H i s found, 2) males with CBAVD, 3) non-
cl assi c CF (?)

84
Q

c o nd i t i o ns f o r c a r r i e r s c r e e ni ng f o r s e p h a r d i c j e w s ?

A

Tay-Sachs - 1/45 inMoroccanJews; low and same as non-Jewish inother
S e p h a r d i c J e w s - F M F - 1 / 3 - 1 / 7 i n N o r t h A f r i c a n j e w s a nd I r a q i J e w s - b e t a - t h a l - 1/5 inKurdish and Iranianjews -alpha-thal - yemenite and iraque jews -G6PD - - screenforthalassemias-screenfortaysachsif Morrocanjewishancestry-G6PD
s c r e e ni ng p r i o r t o o f f e r i ng s u l p h a o r r e l a t e d d r u g s

85
Q

oncogenes and their diseases

A

RET (MEN2a, b, familial medullary thyroid cancer) MET (hereditary papillary

renal carcinoma)

86
Q

tumor suppressors - gatekeepers

A

RB1, TP53

87
Q

tumor suppressors - caretakers

A

mismatch repair, TP53

88
Q

etiologies of congenital SNHL

A

25% idiopathic 25% non-genetic 50% genetic 30% syndromic 70% nonsyndromic 1-
2% XL 15-24% AD 75-85% AR 50% DFNB1 (GJB2/6) 50% al l other DFNB loci

89
Q

AD deafness syndromes

A

Waardenburg - most common, pigmentary abnl of ski n, hair, eyes BOR - 2nd most
common. all types of HL, external ear malformation, branchial cysts/fistulae, renal
mal form’nStickler - progressi ve SNHL, cl eft pal ate, spondyloepiphyseal dysplasia

NF2 - HL secondary to vestibular schwannomas

90
Q

AR deafness syndromes

A

Usher - most common. congenital SNHL, devel op RP. Pendred - 2nd most common,
congenital SNHL, euthyroid goiter, Mondi ni mal formati onor dilated vestibular

aqueduct onCT of temporal bone JNL Biotinidase deficiency Ref sum-
progressi ve SNHL and RP. Treatable! metabol i c.

91
Q

XL deafness syndromes

A

Al port - postlingual progressi ve SNHL, kidney fai l ure, ophtho findings. (85% XLR,

15% AR, al so AD reported) Mohr-Tranebjaerg

92
Q

FGFR3 disorders (GoF or LoF ?)

A

achondroplasia (GoF Gl y280Arg) hypochondroplasa (GoF N540K, others)
thanatophoric dysplasia (GoF , heterogeneous?) SADDAN (GoF ? Lys650Met)
Crouzonwith acanthosis nigras (Al a391Gl u) nonsyndromic coronal synostosis

Muenke synd.

93
Q

FGFR2 disorders (GoF or LoF ?)

A

Crouzonsyndrome (GoF ) Jackson-Wei ss syndrome (GoF Apert (GoF , P253R-
syndactyly more common, S252W-cleft pal ate more common) Pfeiffer (GoF isolated

coronal synostosis (GoF

94
Q

FGFR2 craniosynostosis and their distinguishing features

A

Crouzon- normal hands, feet, greatest proptosis, parrot-beak nose, mandibuar
prognathism, al l el i c heterogeneity apert - greatest risk for MR/DD (50%),
syndactyly of hands and feet (mittenhand), P253R and S252W Pfeiffer - type 1
al so caused by FGFR3 mtn(5%), broad, short, medially deviated thumbs and big
toes, type 2 and 3 more severe beare-stevenson- normal hands and feet, all have
MR, abnl ears, GU and skin abnlts Jacson-Wei ss - normal hands, broad medially
deviated big toes, abnormal tarsals in feet, Muenke - FGFR3 (not 2!) -

95
Q

which coronal craniosynostosis syndrome i s NOT caused by anFGFR mutation?

A

Saethre-chotzensyn- TWIST1 mtns, del s, dups # Low frontal hairline, ptosis,
strabismus, facial asymmetry Small ears with a prominent crus Li mb anomalies

96
Q

which skeletal dysplasia is AR?

A

diastrophic dysplasia mtns in SLC26A2 (DTDST) @ 5q32-q33.1

97
Q

what are the three stop codons?

A

UGA -U Go Away UAA-U Are Away UAG-U Are Gone

98
Q

Which repeat disorders involve CAG repeats and polyglutamine expansion?

A

Huntington- SBMA SCA 1,2,3,6,7,17 DRPLA (Dentatorubropal lidoluysi anatrophy)

99
Q

Which repeat disorders involve repeats in introns?

A

Fredreich ataxia (only AR) (GAA in intron1)

100
Q

Which repeat disorders involve repeats in UTRs?

A

Fragile X (5’ UTR) - CGG Myotonic dystrophy (3’ UTR) - CTG

101
Q

Which repeat disorders expand more frequently in spermatogenesis?

A

HD (can occur in both, but big jumps happen in spermatogenesis) SCAs with CAG

repeats (except SCA8)

Final Review GC (7 decks)

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