This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
. All of the following forms of porphyria are associated with peripheral neuropathy except 
Select and explain. 
A. acute intermittent porphyria, B. hereditary coproporphyria, C. porphyria cutanea tarda, D. variegate porphyria
C: porphyria cutanea tarda
Answer: C: porphyria cutanea tarda 
Explanation: Porphyria is a group of inherited disorders caused by defects in heme biosynthesis. Three forms of porphyria are associated with peripheral neuropathy: acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). The acute neurologic manifestations are similar in each, with the exception that a photosensitive rash is seen with HCP and VP but not in AIP. Attacks of porphyria can be precipitated by ceain drugs (usually those metabolized by the P450 system), hormonal changes (e.g., pregnancy, menstrual cycle), and dietary restrictions. Ref Harrison 20th edition page 3211