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NBME 21 Answers

nbme21/Block 1/Question#6

A normal-appearing 17-year-old girl has never had a ...

Androgen insensitivity syndrome

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 +8  upvote downvote
submitted by ergogenic22(142),

chromatin negative = no barr bodies = person with XY genotype or XO because anytime you have more than one X chromosome you have a barr body (chromatin positive)





 +2  upvote downvote
submitted by hyperfukus(43),

Also another key is it says normal appearing girl one of the things about the AIS is that they do get secondary sexual characteristics...turner girls don't look normal they'd be short and stubby no boobs fat neck etc





 +1  upvote downvote
submitted by nerdy nik(7),

Turner syndrome-> The girl would have a uterus and streak ovaries.





 +1  upvote downvote
submitted by soph(43),

all the other options pt would have uterus, ovaries. turners they wouldnt look normal and they would have atrophic ovaries.

turtlepenlight  This makes sense, but I was thrown off by the "normal-appearing" b/c wouldn't AIS pts not have pubic hair? +  
drzed  They just say it's a normal appearing 17 year old girl; not that the external genitalia are normal appearing. +1  




 -10  upvote downvote
submitted by nosancuck(59),

Yo dis B got NO INTERNAL FEMALE ORGANS

Why dat!???

We be lookin at someone with an SRY from dere Y chromie! Dey be a Y chromie Homie so they be makin some Testis Determinin Factor which I be sure makes some nice lil ANTI MULLERIAN FACTOR so dey aint got that Female Internal Tract u know what i be sayin

And since wimminz is da DEFAULT they stil be gettin dose pussy lips and breastes

meningitis  The above explanation is correct (disregarding the hard to read and unprofessional dialect) but just in case anyone was wondering: chromatin-negative= Just a quick way of knowing it was a boy. The term applies to the nuclei of cells in normal males as well as those in individuals with certain chromosomal abnormalities +11  
yotsubato  Turner syndrome patients are also chromatin negative as well though.... +3  
sympathetikey  I didn't know a complication post-meningitis was lack of humor. +2  
sympathetikey  Ah, didn't read the last line. Yeah, that is taking it a bit far +3  
niboonsh  yall are haters. this is the first explanation that has ever made sense to me +2  
arkmoses  https://www.youtube.com/watch?v=yuXL-3eoB-o&t=77s Interesting syndrome watching this helped me to put it into real life perspective, interesting points they have no pubic hair/body hair, they apparently also dont smell, and breast size is usually increased... +1  
whoissaad  How does chormatin-negative indicate a normal cell? Isn't chormatin just condensed DNA? +1  
cienfuegos  According to this paper most individuals with Turner Syndrome are chromatin negative: "One of the initial laboratory procedures used to confirm or rule out this diagnosis involves a sex chromatin determination from a buccal smear. Cells from the lining of the mouth are stained for the presence or absence of X-chromatin or Barr bodies, which represent a portion of an inactivated X chromosome. The typical Turner’s syndrome patient, who has 45 chromosomes and only one sex chromosome (an X), has no Barr bodies and is, therefore, X-chromatin negative. This abnormal X-chromatin negative finding in the majority of Turner’s syndrome females is similar to the result found in a normal male, who also has only one X chromosome, and differs from the X-chromatin positive condition observed in the normal female, who has two X chromosomes. Occasionally, the patient with features of Turner’s syndrome is found to be X-chromatin positive." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6233891/ +1  
hyperfukus  i really hate haters this is awesome! +  
selectuw  to add to the above, free testosterone is aromatized to estrogen leading to breast development +  




one does not simply “walk into morder”