USMLE-Rx Step 1 Practice Q's

USMLE-Rx Step 1 Qmax Challenge #1278

Check out today’s Step 1 Qmax Question Challenge.

Know the answer? Post it below! Don’t forget to check back for an update with the correct answer and explanation (we’ll post it in the comments section below).

usmle-rx-step-1-qmax-challenge-1278A 30-year-old woman is found unconscious in her home by her husband. On arrival in the emergency department, she is noted to have thin, translucent skin over her abdomen with prominent varicose veins and many bruises on her shins. He denies any major medical problems in her past, though does report that she always seemed to “bruise really easily.” Her husband thinks the patient’s mother may have had similar problems with bruising, and also that she had “some sort of surgery” when her intestine was found to “have a hole in it.” An autopsy is performed, and an abnormality is discovered in the circle of Willis, similar to that shown in the image.

Which of the following proteins was most likely defective in this patient?

A. Fibrillin-1
B. Keratin 14
C. Type I procollagen
D. Type III procollagen
E. Type IV collagen

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6 replies »

  1. I think mutation in “Type III procollagen” would be the answer, and this patient is a case of “Ehlers–Danlos syndrome” which can be transmitted by “Autosomal Dominant” pattern ( Her mom had some manifestation probably diverticulosis) and Aneurism which is seen in this angiography.

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  2. Correction of the above .
    Correct answer D : EDS vascular type follows autosomal dominant inheritance. Is caused by abnormal changes (mutations) of the gene known as collagen type III, alpha-1 (COL3A1), which is located on the long arm of chromosome 2 (2q31).

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