nbme20/Block 2/Question#32

A 12-year-old girl is brought to the physician by ...


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submitted by hayayah(216),

A big thing here too is noticing that the ALP is decreased. Osteoblast activity is measured by bone ALP. I think that was the main focus here and not that you necessarily need to know the CBFA1 gene mutation.

sympathetikey  Exactly. That's the only way I got to the answer. +  

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submitted by monoloco(27),

This is a conditional called craniocleidodysplasia. The kid on Stranger Things with the lisp has the disorder. No collar bones, too many teeth, frontal bossing => craniocleidodysplasia. CBFA1 is a gene highly implicated in osteoblast function.

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submitted by thomas(5),

They tell you that the kid has no clavicle. This means the defect is in membranous ossification, NOT endochondral, so the pathology is NOT going to involve the chondro-whatever cells. decreased ALK is consistent with osteoblast defect.

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submitted by usmleuser007(13),

To answer this question is to note that: 1) alkaline phosphatase activity is linked with osteoblasts.