Porphyria cutanea tarda (PCT), a manifestation of deficiency of uroporphyrinogen decarboxylase (UROD) in the liver
Porphyria cutanea tarda (PCT) is caused by a deficiency of uroporphyrinogen decarboxylase (UROD) in the liver. UROD is a branch point enzyme which is responsible for the biosynthesis of tetrapyrroles. It leads to heme and chlorophyll biosynthesis by catalysing the decarboxylation of four acetate groups of uroporphyrinogen III for yielding coproporphyrinogen III. PCT is strongly associated with hepatitis C virus (HCV) infection in Southern Europe. In addition, there is a high prevalence of the viral infection in some geographic areas. However, despite its association with HCV infection, PCT is considered a rare complication. Literature further states that the susceptibility factors are prevalent in only some patients. Patients with PCT also show high iron accumulation compared to HCV infected patient without PCT.
This article describes the case of a 65-year-old male patient who presented to the dermatology clinic with worsening lesions on his hands with a history of 6 months. The lesions were also visible on the patient’s forearms with fingernail thickening. The patient’s medical history was significant for end-stage renal disease and an untreated viral hepatitis C infection. Physical examination further showed crusted erosions and atrophic scars on the dorsal hands and forearms, scattered around the tense vesicles of the fingers and forearms.
Investigations and treatment
Other findings included onychodystrophy and subungual hyperkeratosis of the fingernails. Doctors further advised a 24-hour urine sampling which showed elevated levels of of uroporphyrins. Based on these findings, the patient was diagnosed with porphyria cutanea tarda. The condition is either acquired or inherited because of a uroporphyrinogen decarboxylase deficiency. In addition, the risk of development of the condition increases because of smoking, alcohol, use, certain medications and hepatitis C or human immunodeficiency virus infection.
For treatment, doctors started the patient on sofosbuvir–velpatasvir, in addition to advising the patient on avoiding long hours in the sun. 4 months after the presentation, the lesions and fingernail changes had subsided. At follow-up there was only minimal residual blistering of his forearms.
References
Porphyria Cutanea Tarda Associated with Hepatitis C https://www.nejm.org/doi/full/10.1056/NEJMicm2035140
