WBR1006

{{WBRQuestion |QuestionAuthor=Vidit Bhargava, M.B.B.S [1] |ExamType=USMLE Step 1 |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |SubCategory=Dermatology |MainCategory=Pharmacology |MainCategory=Pharmacology |SubCategory=Dermatology |Prompt=A 35 year old female presents with a 2 week history of sensitivity to sunlight. Whenever she steps outside unprotected she develops blistering, scarring, pigmentation on the back of her hands and face. She has also noticed increased hair growth at unusual places during these past 2 weeks. She is sexually active and takes oral contraceptives regularly. The physician orders the following labs:

Complete blood count:

• Hemoglobin 12.0 mg/dL
• Hematocrit 45%
• RBC's 4 million/cc
• WBC's 8000 /cc
• Platelets 3 lac/cc

LFT's
AST 100 IU/L
ALT 90 IU/L
Prothrombin time 20 secs Bilirubin 2.0

Urinalysis:
Color - pale
pH – 5
Specific gravity – 1.010
Ketones – None
Nitrates – Negative
Leukocyte esterase – Negative
WBCs - ≤2-5 WBCs/hpf
Casts – 0-5 hyaline casts/lpf
Crystals – none
Uroporphyrin Elevated
Porphobilinogen Normal

USG: Normal liver architecture

The patient is diagnosed with an enzymatic defect in heme metabolism, which of the following indicates the disease and the associated enzymatic defect?

[[Image:Heme synthesis copy.jpg|300px] |AnswerA=Congenital erythropoietic porphyria; uroporphyrinogen III synthase |AnswerB=Porphyria cutanea tarda; uroporphyrinogen III decarboxylase |AnswerC=Acute intermittent porphyria; porphobilinogen deaminase |AnswerD=Variegate porphyria; protoporphyrinogen oxidase |AnswerE=Acute porphyria; ALA dehydrogenase deficiency |RightAnswer=B |Approved=No }}