21 - 124 - PORPHYRIAS

Question 1

Question 2

Porphyria cutanea tarda is caused by inhibition of what enzyme

Answer 2

hepatic uroporphyrinogen decarboxylase (UROD) activity

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

The most common porphyria in children is treated with

A. Hemin

B. Stem cell transplant

C. Phlebotomy

D. Oral Charcoal

Answer 14

C

PCT is the most common porphyria, P. 2237. Treatment with phlebotomy or low-dose hydroxy- chloroquine is highly effective in both sporadic and familial forms of PCT. p. 2342

Question 15

The enzyme affected in most common acute hepatic porphyria is

A. ALAD

B. UROD

C. HMBS

D. FECH

Answer 15

C AIP is the most common acute hepatic porphyria worldwide P.2250 At least 400 PBGD/HMBS mutations have been iden- tified in AIP P.2250

Question 16

Treatment of choice in young with severe congenital erythropoietic porphyria

A. Hemin

B Stem cell transplant

C. Phlebotomy

D. Oral Charcoal

Answer 16

B

Hematopoietic stem cell transplantation is curative and is the treatment of choice for young patients with severe disease. P. 2244

Question 17

A 50 yo female presented with skin friability and c blistering lesion on the dorsal aspects of hands. Laboratory result showed increase total plasma porphyrin and predominance of highly carboxylated porphyrins. Which factor is mostly associated with the case:

A. Alcohol use

B. Smoking

C. Chronic Hepatitis C

D. Estrogen use

In relation to the case, what enzyme is affected:

A. ALAD

B. UROD

C. HMBS

D FECH

Answer 17

D.

Female. Estrogen use is common in women with PCT.2239

PCT is the most common porphyria, and is characterized by the development of skin friability and chronic, blistering lesions on the dorsal aspects of the hands and other sunexposed areas of skin usually in mid- or late life.

B. UROD

Question 18

develops as an acquired deficiency of the fifth enzyme in the pathway with or without a mutation

Answer 18

porphyria cutanea tarda

Question 19

All but one arise from mutation of a pathway enzyme, the exception is?

Answer 19

porphyria cutanea tarda