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    X-Linked Protoporphyria

    Important
    It is possible that the main title of the report X-Linked Protoporphyria is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

    Synonyms

    • XLP
    • XLDPP
    • X-linked dominant protoporphyria

    Disorder Subdivisions

    • None

    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.

    Resources

    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
    Internet: http://www.CLIMB.org.uk

    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
    Internet: http://www.porphyriafoundation.com

    Erythropoietic Protoporphyria Research and Education Fund
    Channing Lab
    Harvard Medical School
    181 Longwood Avenue
    Boston, MA 02115
    Tel: (617)525-8249
    Tel: (800)638-6294
    TDD: (617)732-6458
    Email: mmmathroth@rics.bwh.harvard.edu
    Internet: http://www.brighamandwomens.org/Patients_Visitors/patientresources/patienteducation/eppref/

    British Porphyria Association
    136 Devonshire Rd
    Durham City, DH1 2BL
    United Kingdom
    Tel: 01474369231
    Email: helpline@porphyria.org.uk
    Internet: http://www.porphyria.org.uk

    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
    TDD: (888)205-3223
    Internet: http://rarediseases.info.nih.gov/GARD/

    Norwegian Porphyria Centre
    Haukeland University Hospital
    Postboks 7804
    Jonas Liesvei 65
    Bergen, NO-5021
    Norway
    Tel: 4755973050
    Fax: 4755973115
    Email: porfyri@helse-bergen.no
    Internet: http://www.napos.no

    For a Complete Report:

    This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, 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. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

    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.

    For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

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

    WebMD Medical Reference from the National Organization for Rare Disorders

    Last Updated: May 28, 2015
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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