Final answer:
Deficiency of uroporphyrinogen decarboxylase causes Porphyria cutanea tarda.
Step-by-step explanation:
Deficiency of the enzyme uroporphyrinogen decarboxylase, which converts uroporphyrinogen III to coproporphyrinogen III in the heme synthesis pathway, causes Porphyria cutanea tarda. Porphyria cutanea tarda is a disorder characterized by the abnormal accumulation of porphyrins, resulting in photosensitivity and skin fragility.