Huntington Disease is a neurological disorder characterized by a classic triad of choreiform movement (in this case the bilateral writhing motions of the upper extremities), dementia/depression, and behavioural changes (aliens).

Per UW, evaluation of fetal demise includes fetal autopsy, gross and microscopic examination of placenta, membranes, cord, and karyotype and genetic analysis. Evaluation of fetal demise on moms side includes kleihauer betke test for fetomaternal hemmorhage, antiphospholipid antibodies and coag studies.

Nobody has answered this question through the lens of a learning objective quite yet so here's my 2 cents: Km is INCREASED bc this patient has an enzyme with an overall LOWER affinity (can be corrected to normal after an increase in substrate) which is characteristic of COMPETITIVE inhibition, which is why the line of the pt. is one of competitive inhibition on a LB plot

Alcohol withdrawal - - > increased catecholamines - - > increased insulin (via B2) - - > cellular uptake of K+ - - > hypokalemia

This question might be tricky because the mutation of interest here is inherited from the dad side (paternal) but affects the mitochondria.

That is, the mutation is not a mutation of the mitochondrial DNA.

In their explanation, the NBME says, “Mitochondrial diseases are strictly inherited through the mother” but that is incorrect; it would be more correct for them to have said: Mitochondrial DNA mutations are strictly inherited through the mother.

In other words, the stem does not describe a "mitochondrial disease" in the way the NBME defines it.

Yes, mitochondria are affected but the mutation is in nuclear DNA that govern the maintenance of "healthy mitochondria". The mutation affects the function and operation of mitochondria but the mutation itself is in the nuclear DNA (which control something about the "quality" of mitochondria but what exactly is not yet understood).

This explains why dad and dad's brother show the same “proximal muscle weakness of the lower extremities”.

Both histoplasmosis and blastomycosis are associated with living in Ohio and can cause pulmonary disease. Histoplasmosis is more associated with hilar lymphadenopathy and can cause cavitations (recall from Sketchy that it can resemble Tb) - another association to note with Histo is hepatosplenomegaly. Blastomycosis is uniquely associated with extra-pulmonary involvement in the bone, prostate, and skin

I got this right because I thought of the cavernous sinus which has CN 3, CN4, CN V1 & V2. Out of all of all the options V2 is the only one that controls upper lip. For option C, pupillary reflex is controlled by CN 2 and 3, and if there is a fracture to the orbital floor the closest to the sinuses to be injured is CN5 (V2). Idk I could be wrong but if you guys agree let me know pls.

Mom and her daughter have the same sequence of FBN1. What is special is that compared to a “normal” (wild-type) FBN1, mom and daughter have one little tiny mutation in their sequence: a single nucleotide (A,T,G,C) that is different than most other folks.

(Interestingly, this nucleotide difference does not alter the amino acid encoded by this part of the gene; that makes Choice D (change the folding of the protein) and Choice E (truncated protein) very unlikely.)

Back to our question. Even though mom and daughter have the same mutation, mom shows no signs of Marfan syndrome; this eliminates Choice A (disease-causing mutation in the patient and her mother).

You might think this is an example of variable expressivity (not an option but a good guess), and it might be.

In the stem they say:

The same nucleotide change is found in 15 of 200 individuals without Marfan syndrome.

Interesting! This means that in a “normal” sample of people (who have no signs of Marfan), 15 out of 200 still have this mutation.

(They don't say anything about how many Marfan people have the mutation but we don't need that information to answer the question.)

When a gene can be found in multiple “versions”, we call the gene polymorphic (literally, many-shapes or many-forms).

So the best response is Choice B (polymorphism).

The graft is placed below the renal arteries and above the aortic bifurcation, which contains the IMA. IMA supplies the hindgut (distal 1/3 of transverse colon to to upper portion of the rectum).

FA 2019 pg. 357

So are we just not going to talk about how an NBME question writer just sketched this real quick and put it on a question

I always remember locus caeruleus as Marcus Aurelius (if anyone has seen the movie Gladiator) its about action and being hopped on up Nor epi would recommend

My two Leishmania questions were literally back to back lol

I don't believe this question is addressing hereditary angioedema (which is definitely a manifestation of C1-INH deficiency), but rather just overactive complement (since its inhibitor is deficient). Remember that byproducts of the complement cascade include C3a, C4a, and C5a, which are all anaphylatoxins. "Episodes of cutaneous urticaria and occasional episodes of laryngospasm" describes an allergic reaction that can be mediated by the anaphylatoxins produced in the cascade. The other answer choices would lead to decreased complement activity and therefore release of fewer anaphylatoxins.

So I thought about the "tombstone" picture on p.207 of Pathoma where the desmosomes are defective. The cells in the basal layer stay attached to the basement membrane, but the cells above get disconnected. So that made me think of breaking the connection between cells in the basal layer and cells above the basal layer (suprabasal).