X-Linked Protoporphyria

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report X-Linked Protoporphyria is not the name you expected.

Disorder Subdivisions

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General Discussion

Summary

X-linked protoporphyria is an extremely rare genetic disorder characterized by an abnormal sensitivity to the sun (photosensitivity) that can cause severe pain, burning, and itching of sun-exposed skin. Symptoms may occur immediately or shortly after exposure to the sun, including direct exposure or indirect exposure such as sunlight that passes through window glass or that is reflected off water or sand. Redness and swelling of affected areas can also occur. Blistering and scarring usually do not occur. Chronic episodes of photosensitivity may lead to changes in the skin of sun-exposed areas. Some individuals eventually develop potentially severe liver disease. X-linked protoporphyria is caused by mutations of the ALAS2 gene and is inherited as an X-linked dominant trait. Males often develop a severe form of the disorder while females may not develop any symptoms (asymptomatic) or can develop a form as severe as that seen in males.

Introduction

X-linked protoporphyria belongs to a group of disorders known as the porphyrias. This group of at least seven disorders is characterized by abnormally high levels of porphyrins and porphyrin precursors due to deficiency of certain enzymes essential to the creation (synthesis) of heme, a part of hemoglobin and other hemoproteins. There are eight enzymes in the pathway for making heme and at least eight different forms of porphyria. The symptoms associated with the various forms of porphyria differ. It is important to note that people who have one type of porphyria do not develop any of the other types. Porphyrias are generally classified into two groups: the "hepatic" and "erythropoietic" types. Porphyrins and porphyrin precursors and related substances originate in excess amounts chiefly from the liver in the hepatic types and mostly from the bone marrow in the erythropoietic types. Porphyrias with skin manifestations are sometimes referred to as "cutaneous porphyrias." The term "acute porphyria" is used to describe porphyrias that can be associated with sudden attacks of pain and other neurological symptoms.

X-linked protoporphyria is an erythropoietic form of porphyria and is extremely similar clinically to erythropoietic protoporphyria (EPP). X-linked protoporphyria was first described in the medical literature in 2008.

Supporting Organizations

American Porphyria Foundation

4900 Woodway, Suite 780
Houston, TX 77056-1837
Tel: (713)266-9617
Fax: (713)840-9552
Tel: (866)273-3635
Email: porphyrus@aol.com
Website: http://www.porphyriafoundation.com

British Porphyria Association

136 Devonshire Rd
Durham City, DH1 2BL
United Kingdom
Tel: 1474369231
Email: helpline@porphyria.org.uk
Website: http://www.porphyria.org.uk

CLIMB (Children Living with Inherited Metabolic Diseases)

Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174
Email: enquiries@climb.org.uk
Website: http://www.CLIMB.org.uk

Erythropoietic Protoporphyria Research and Education Fund

Channing Lab
Harvard Medical School
Boston, MA 2115
Tel: (617)525-8249
Tel: (800)638-6294
Email: mmmathroth@rics.bwh.harvard.edu
Website: http://www.brighamandwomens.org/Patients_Visitors/patientresources/patienteducation/eppref/

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
Website: http://rarediseases.info.nih.gov/GARD/

Norwegian Porphyria Centre

Haukeland University Hospital
Postboks 7804
Bergen, NO-5021
Norway
Tel: 4755973050
Fax: 4755973115
Email: porfyri@helse-bergen.no
Website: http://www.napos.no

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  3/10/2013
Copyright  2013 National Organization for Rare Disorders, Inc.