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NBME 22 Answers

nbme22/Block 2/Question#34 (reveal difficulty score)
A 30-year-old man and a 24-year-old woman ...
1 in 600 ๐Ÿ” / ๐Ÿ“บ / ๐ŸŒณ

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submitted by โˆ—bubbles(79),
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choirCn larne :siccinfeyuinf

)1 poro ephptsoah acnerecla t-;-&g ihhg sermu rciaongin ushopoprsho

2) gihh eurms htphespoa g;-&t- cesxmpeol with edntvali cotina Ca gt&--; Ca lalfs

3) Ca lfasl -;tg-& riggstre PTH xsai

4) ndkyei eifarul --t;g& dceeeasdr ttvyiiac of derlah1-oysxy at teh nyiked -tg-;& ssel cciatlrilo

submitted by โˆ—drdoom(1193),
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ocnaluCatlis orf dad. hTe rtyabbpiloi fo eth aehrft bnige a rrceira si 2/3 niesc ti is kownn that eh dneotsโ€™ eahv het hneT het iiaolpbrybt of him snaipsg ti on ot ish ikd si 12/, :huts

  • rPyilbbaoti of dad inegb rircrae = /32
  • tiiolabrPby of add sinpasg on ssdiaee lealle = /21

ilaluaocnCts rfo omm. tihW teh bayerHeringdW- nriPc,plei ouy nac ugfrie tou eht iyabtiolrbp of teh hreotm nebig a r:airecr

q = 0)0(q,t/00rs14 = /1020

So, q2p = 2 * 10/20 * 092109/, hcwhi si ppoarx /.0011

rFo eht chidl to get teh lleael form mom, owt gsihnt edne ot p:aephn (1) mom mtsu eb a rairecr โ€[zteg]reetโ€œyhoo nad (2) mom mtus pssa the eallel ot li:hdc

  • alitiobrPyb fo mom ibeng rarreic = 1/010
  • iitlbaPrybo fo omm ssgianp on esedsai aelell = /12

nutgPi ti all hrtoeetg. woN, oebnimc lal ethgoe:tr

= lbbiroipya(t fo dad nigbe )crerria * (orabtplibyi fo dad nassgip no ieaseds ela)lle * ilr(ipbayotb of omm gbnei ir)caerr * a(bpoyirtbli of omm npsaigs no aedsise lleae)l

= 2/3 * 1/2 * /0101 * /12
= 1 in 600

kernicterusthefrog  To uoqet yhgorT hor,T rdga euen:q w",e se,sJu rsogs" +52  
niboonsh  ihsT unqoeits kemas me ntwa ot viotm +14  
drdoom  llo +  
5thgencephalosporin  kayo wow +  
tekkenman101  ouY acn eakm iths a tol rkqciue yb guisn lmeips uselr orf tlasoomau ssevcreie 1ise)da.ess aneUfdefct etanrp hitw fcefdeta agnliee lliw be a iecarrr 23/ fo the ietm 2 A()a) ceyequfrn ni loatnupopi is rsepu lwo os oyu nca ingore P nad ujst eus q(2) ni drero ot tcuacella ricraer cefqrn.yeu So aket hte eqrsua otro of the yozghmouso siceevesr qenrcuyfe 0,/004)1(0 dna jstu uglp ti :in )(.5002 = 31 0). heT dods of rteih dhlic ibgen ctfefade whit hte owt peratsn ibnge seduasm hyipechaltot riecarrs is 41/ aa() or D.5.'ads2 ciearrr echcna /3)2( x M'som rcrraei nechac 0(.1) x dch'sli nahcce fo nbieg ivceeessr )5(.2 +1  

Instead of doing all those calculations for the mom, you can also just multiply the dad's probability by 1/200 โ†’ q, the probability of the allele in the general population

+/- hungrybox(1275),

submitted by โˆ—keycompany(351),
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nnalMdiae ecenit:Gs

anM ahs 2/3 achenc fo neibg a eircr.ra H(e sdeo ton hvea teh ads)see.i mWnao ecirarr sirk muts eb tducalcela hiwt 2^p + q2p + ^q2. ^q2 = /,004100 q = 00/,21 p si hulrgoy = 1q2p = 1100/ = raieCrr fnyrqecue .

iksR fo nahvgi a ihlcd utsh elqaus 32/ x 1/100 x /14 = 010/6/ca B: uees32 = anM Carerri rksi 0 /011 = aelemF airrerC k1sR i4/ = acCehn yteh ache apss no teh eersivecs egne ot eithr igso.pnffr

hello  See my xnatopnlaei if uyo dene more dorsw ot anlpixe sthi npaloaintxe +2  

submitted by โˆ—hello(428),
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hsTi hte ames as n'cyemoya@psk iatnlxponea tihw emro enaxtiaonlp othse thta ndee ..i.t

ehT pantite is ecenfafdtu yb hte itlacurapr omuoatals esescveir eisased adn ish orberth ash eth ausaolomt iscsvreee isdseea t;g--& ihst nsema chae fo hriet rsteanp scarire eht RA l.lelea o,Nw rof eht pieantt ot eb ffeactuedn enivg taht bhot hsi nretsap aehv the AR llleea, it esman ttha eht teaintp hsa a 3/2 ancech thta he si ilmsoyunlesaut tdnecaeuff dan a rrac.rei

heT tneiapt's aeprrnt is cfndfeutae dna monalr ind-beyeWHrgar teigscne s(a ttsade ni the hm.oeprlwneb.) isth is lsipilacfcye i,dmneotne yuo ear to uesams hatt hte arpnert hsa a irearcr qecryunfe fro het RA eael,ll ihwhc aquel to p.q2

hTe sasdeie sah a qfyruecen in het ooniptalpu of /00010.4 hsiT is 2^q g-&t;- 2q^ = 0000.4/1 lvngoiS orf ,q ouy teg q = .0/021

erirrCa enufqceyr si .p2q voeeHrw, orf a erar daeesis, 2pq โ‰ˆ q.2 ,So hte rreiarc cnefryque for hte reatnrp = q2 = 2 * /2001 = /.0110

N,wo het Q asks aoubt an irspfgfon fo eth ttpniae adn ihs prntera enbgi fdfaetce, so ot evah na etafefcd cdli,h htere is a /14 ecanch of vgniah na adefceft dhcil eesa(bucs teh aiptnte dna eth penrrat obth hvea a 2/1 heccan fo asgisnp eht eallle ;--tg& uoy etipumll shete getretoh 2/1 * 2)/1.

So, tmplyuil /32 * 100/1 * 14/ = /0.061 Thsi si nPtea(tpi genbi a )aerircr * aretpr(Pn nbegi a cri)rare * ng(hvaPi an dceeftfa ngfpofirs eeotgt.rh)

submitted by beastfromtheastx(0),
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eTh iraibylpbot of het aertfh bgein a rrrieca si 32/ eicns ti si onnwk hatt eh toโ€™desn ehav eth essea.di henT het byoptairilb fo imh asinsgp ti on ot his ikd i:s

1/2 * 23/ = /13

ihtW teh eebynirHaWdrg- erlipPin,c you can regiuf out eth iraptbiboly fo het hoemrt ngibe a rreci:ra

q = st,r/q00)(4010 = 0/120

o,S 2pq = 2 * 0/210 * 919/002, hwcih apoxrp is /101,0 dan the iyolbitbarp of teh idclh gitentg shti llalee is 10/01 * 21/ = 02/01


012/0 * 31/ = 60/10

brill45  uoY did hsit gtihr but I htkin adem it a tib meor mateclopcdi tanh ddenee ot .eb oT uirfeg tou hte olieikdhlo of a dnrmao prseno ni hte lounpiotap assnpgi on a ssecverie ,eallel uyo tjsu eedn ot od )2ur(eroqaqost to get to .q dAn tsju eus that q to imylplut wtih the 31/ yuo got ehT q uevla llest uyo the laelel uyeefcnrq in the iouolpptn,a ehwtreh het sneorp si a cearrri ro hogyumzsoo rvesseiec obt.h ouY tills ogt ti, utb juts tletgin oyu kwno eth sireea rtoue in scae yuo ese it ai!nga +2  

submitted by kdckjn(0),
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hwy rhete si biayrotiplb of faerht bineg a raecrir si 2/3

drdoom  We uaemss isht is a seircseev dsasie.e In rohet dswor, uyo teasnfim hte ssdaiee fi ouy nthirei a dsaesei ,elalel ,d omrf uyro tmreho dna a iasedse la,elle ,d mrfo yruo e,hfrta ngivig uyo na alleel ngraipi edentdo by .dd dd = you aehv the easieds. heT hrfeat seod ton aveh eht ad;seies thsi mnsae sih teynopge acn lony eb 1 fo rheet nit:ghs D,D ,dD or d.D tTha i,s DD = D frmo his da,d D rofm ish omm; Dd = D rofm sih ad,d d rmfo ish mm;o or dD = d mrfo hsi dad, D rmfo sih iNcoet taht ni only two fo ethse 3 tsspesliibioi deos the ethfar len(ytaop)ilt eavh a dseseia elllea (d) that he mtgih sasp on ot ihs nepyrgo. +  

We assume this is a recessive disease. In other words, you manifest the disease if you inherit a disease allele, d, from your mother and a disease allele, d, from your father (giving you the allele pairing denoted by โ€œdd โ€).

dd = you have the disease.

The father does not have the disease; this means his genotype cannot be dd and thus must be one of 3 things: DD, Dd, or dD.

That is,

  • DD = D from his dad, D from his mom;
  • or Dd = D from his dad, d from his mom;
  • or dD = d from his dad, D from his mom.

Notice that in only two of these 3 possibilities (โ…”) does the father (potentially) have a disease allele, d, that he might pass on to his progeny.

+1/- drdoom(1193),

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