Question

Uroporphyrinogen III is converted to coproporphyrinogen III via the enzyme uroporphyrinogen decarboxylase (heme synthesis). Deficiency of this enzyme causes which condition?

1) Porphyria cutanea tarda
2) Hemochromatosis
3) Sideroblastic anemia
4) Thalassemia

Answer 1

Deficiency of uroporphyrinogen decarboxylase causes Porphyria cutanea tarda, a condition characterized by a buildup of porphyrins leading to skin abnormalities.

Step-by-step explanation:

Deficiency of the enzyme uroporphyrinogen decarboxylase, which is involved in the conversion of uroporphyrinogen III to coproporphyrinogen III during heme synthesis, causes the condition known as Porphyria cutanea tarda. If this enzyme is deficient, there is a buildup of porphyrins in the skin, leading to photosensitivity, blisters, and other skin abnormalities that are characteristic of Porphyria cutanea tarda.

This condition is part of a group of disorders termed the porphyrias, which involve problems with the synthesis of porphyrins. Porphyrias can be classified into erythropoietic and hepatic, based on whether the symptoms are predominantly related to red blood cell or liver dysfunction, respectively.