What is the Difference Between Hemochromatosis and Porphyria Cutanea Tarda

The key difference between hemochromatosis and porphyria cutanea tarda is that hemochromatosis is a rare disorder that causes too much iron build-up in the skin, heart, liver, pancreas, pituitary gland, and joints, while porphyria cutanea tarda is a rare disorder that causes painful, blistering skin lesions on the sun-exposed skin.

Heme consists of iron and protoporphyrin. It is an essential cofactor involved in various biological processes such as oxygen transport and storage, electron transfer, signal transduction drugs, steroid metabolism, and micro RNA processing. Heme is also a precursor to haemoglobin. Hemochromatosis and porphyria cutanea tarda are two heme-associated rare disorders.

CONTENTS

1. Overview and Key Difference
2. What is Hemochromatosis 
3. What is Porphyria Cutanea Tarda
4. Similarities – Hemochromatosis and Porphyria Cutanea Tarda
5. Hemochromatosis vs Porphyria Cutanea Tarda in Tabular Form
6. Summary – Hemochromatosis vs Porphyria Cutanea Tarda

What is Hemochromatosis?

Hemochromatosis is a hereditary disorder that absorbs too much iron from the food people eat. This leads to an excess iron build-up in organs such as the liver, heart, and pancreas. Too much of iron can lead to life-threatening conditions like liver diseases, heart problems, and diabetes. The signs and symptoms of hemochromatosis include abdominal pain, fatigue, joint pain, weakness, diabetes, impotence, loss of sex drive, heart and liver failure, bronze coloured skin, and memory fog (lack of focus and mental clarity). Hemochromatosis is caused due to a mutation in a gene that usually controls the amount of iron absorbed from food. This gene is known as HFE. The HFE gene has two common mutations (C282Y and H63D) that lead to hereditary hemochromatosis. Moreover, hereditary hemochromatosis shows an autosomal recessive inheritance pattern.

Hemochromatosis can be diagnosed through blood tests (serum transferrin saturation and serum ferritin), liver function tests, MRI, testing for gene mutation, and liver biopsy. Furthermore, the treatment options for hemochromatosis may include blood removal (phlebotomy) and chelation (removing excess iron through urine or stool by using a medication).

What is Porphyria Cutanea Tarda?

Porphyria cutanea tarda is a rare disorder that causes painful, blistering skin lesions on sun-exposed skin. The affected skin looks fragile and can peel or blister after minor trauma. It can also be caused liver abnormalities. The common symptoms may include blisters on the skin that is exposed to sun, photosensitivity, fragile skin, increased hair growth on the face, crusting, scarring,  redness, swelling or itching of the skin, hyperpigmentation, sores developing after minor injuries to the skin, reddish brown urine, and liver damage.

Porphyria cutanea tarda is caused due to deficiency in levels of uroporphyrinogen decarboxylase (UROD), which is essential for the synthesis of heme. This causes abnormally high levels of porphyrins and porphyrin precursors. Approximately 75% to 80% of porphyria cutanea tarda cases are acquired or sporadic. The remaining cases have a genetic predisposition. Hereditary porphyria cutanea tarda is specifically due to a mutation in the UROD gene. This hereditary or familial porphyria cutanea tarda follows an autosomal recessive inheritance pattern.

Moreover, porphyria cutanea tarda can be diagnosed through medical history, physical examination, blood tests, urine tests, stool tests, and skin biopsy. Furthermore, treatment options for porphyria cutanea tarda include phlebotomy, medications like chloroquine and hydroxychloroquine, pain medications, iron chelators, and treating the diseases that cause the porphyria cutanea tarda like HCV or HIV.

What are the Similarities Between Hemochromatosis and Porphyria Cutanea Tarda?

• Hemochromatosis and porphyria cutanea tarda are two heme-associated disorders.
• Both conditions are rare disorders.
• Both conditions may have similar symptoms, such as hyperpigmentation and liver problems.
• They may have a genetic predisposition.
• Both conditions follow an autosomal inheritance pattern when inherited.
• Both conditions can be diagnosed through physical examination and blood tests.
• They can be treated through phlebotomy and chelation.

What is the Difference Between Hemochromatosis and Porphyria Cutanea Tarda?

Hemochromatosis is a rare disorder that causes too much iron build up in the skin, heart, liver, pancreas, pituitary gland, and joints, while porphyria cutanea tarda is a rare disorder that causes painful, blistering skin lesions developing on sun-exposed skin. Thus, this is the key difference between hemochromatosis and porphyria cutanea tarda. Furthermore, hemochromatosis is mainly hereditary. On the other hand, approximately 75% to 80% of porphyria cutanea tarda cases are acquired or sporadic, and the remaining cases have a genetic predisposition.

The below infographic presents the differences between hemochromatosis and porphyria cutanea tarda in tabular form for side-by-side comparison.

Summary – Hemochromatosis vs Porphyria Cutanea Tarda

Heme is a major part of the hemoglobin, which carries oxygen throughout the body. Hemochromatosis and porphyria cutanea tarda are two heme-associated rare disorders. Hemochromatosis disorder causes too much iron build up in the skin, heart, liver, pancreas, pituitary gland, and joints, while porphyria cutanea tarda disorder causes painful, blistering skin lesions on sun exposed skin. So, this summarizes the difference between hemochromatosis and porphyria cutanea tarda.

Reference:

1. “Hemochromatosis.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 30 Dec. 2020.
2. Bandoim, Lana. “Porphyria CUTANEA TARDA: Pictures, Treatment, and More.” Healthline, Healthline Media, 14 Aug. 2018.

Image Courtesy:

1. “Hemochromatosis liver iron prussian blue” By Joseph Mathew, May Y Leong, Nick Morley and Alastair D Burt – A liver fibrosis cocktail? Psoriasis, methotrexate and genetic hemochromatosis, BMC Dermatology 2005, 5:12. doi:10.1186/1471-5945-5-12 (CC BY 2.0) via Commons Wikimedia
2. “Blister in porphyria cutanea tarda” By Nicolás Hermosilla B.; Gonzalo de Toro; Montserrat Molgó – (CC BY 4.0) via Commons Wikimedia