welcome redditors!to snoo-finity ... and beyond!

NBME 23 Answers

nbme23/Block 2/Question#5

A female newborn develops respiratory distress. Her ...

Osteogenesis imperfecta, type I

Login to comment/vote.

 +5  upvote downvote
submitted by seagull(722),

The underlying mechanism is usually a problem with connective tissue due to a lack of type I collagen. This occurs in more than 90% of cases due to mutations in the COL1A1 or COL1A2 genes. These genetic problems are often inherited from a person's parents in an autosomal dominant manner or occur via a new mutation.


Basically, good f***ing luck!

 +2  upvote downvote
submitted by hungrybox(433),

TLDR: Physical symptoms >> family history or anything else.

Like the other guy said, I got played hard.

I thought:

• poor prenatal care

• no family history

• bone problem/fractures

Instantly pointed to Rickets.

BUT, in retrospect this is key:

• intercostal retractions (vs. rachitic rosary → costchondral thickenings)

They're basically telling you to rule out Rickets. It seems 100% unfair b/c poor prenatal care seemed to rule in Rickets. The no family history seems to rule out OI.

But I guess what I've learned is, physical symptoms trump ANYTHING ELSE on NBMEs.

 +2  upvote downvote
submitted by nukie404(6),

At first I was thinking aha! Child abuse! But I guess wormian bones are more suggestive of OI, although the no family hx part was rather bleh.

thotcandy  Literally had it on OI until I saw no family hx... Isn't it AUTOSOMAL DOMINANT? +1  

How is this the answer if there is no family history of recurrent fractures? I thought osteogenesis imperfecta was autosomal dominant?

seagull  Exactly!! it's an autosomal dominate disease! +1  
emcee  Autosomal dominant diseases are variably expressive. Still, I think this was a badly written question (should have given us some family history). +  
wutuwantbruv  Also, FA says that fractures may occur during the birthing process, which is what I believe they were going for. I don't believe these findings would be seen at birth with any of the other choices. +  
d_holles  Yeah I thought I outsmarted NBME by selecting Rickets bc it said no family history ... guess I got played lol. +7  
jean_young2019  Could it be a sporadic cases? Spontaneous Mutation This is a change in a gene that occurs without an obvious cause, in a family where there is no history of the particular gene mutation. OI is inherited as an autosomal dominant trait. Approximately 35% of cases have no family history and are called "sporadic" cases. In sporadic cases, OI is believed to result from a spontaneous new mutation. http://www.oif.org/site/PageServer?pagename=Glossary +4