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Diseases

Genetic and Rare Diseases Information Center (GARD)

Type 1 plasminogen deficiency


Other Names for this Disease
  • Hypoplasminogenemia
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Your Question

My son has type 1 plasminogen deficiency and currently has been diagnosed with ligneous conjunctivitis. Please provide any and all information that you have with respect to this disease.

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is type 1 plasminogen deficiency?

Type 1 plasminogen deficiency is a genetic condition associated with inflammed growths on the mucous membranes, the moist tissues that line body openings such as the eye, mouth, nasopharynx, trachea, and female genital tract. The growths may be triggered by local injury and/or infection and often recur after removal. The growths are caused by the deposition of fibrin (a protein involved in blood clotting) and by inflammation. The most common clinical finding is ligneous ('wood-like') conjunctivitis, a condition marked by redness and subsequent formation of pseudomembranes of part of the eye that progresses to white, yellow-white or red thick masses with a wood-like consistency that replace the normal mucosa. This can lead to vision loss. Growths in other areas can also lead to medical problems; those that occur in the gastrointestinal tract can cause ulcers, and growth in the windpipe can lead to breathing problems. Hydrocephalus may be present at birth in a small number of individuals.[1][2] Type 1 plasminogen deficiency is caused by mutations in the PLG gene. It is inherited in an autosomal recessive pattern.[2] Management depends upon the sites involved, but mainly focuses on managing the ligneous conjunctivitis.[3]
Last updated: 6/13/2016

What are the signs and symptoms of type 1 plasminogen deficiency?

Type 1 plasminogen deficiency is characterized by the formation of inflamed growths on the mucous membranes. The area of the body most commonly affected is the conjunctiva, which are the mucous membranes that protect the white part of the eye (the sclera) and line the eyelids. The most common symptom of this disorder is ligneous conjunctivitis. This occurs when a buildup of a protein called fibrin causes inflammation of the conjunctiva (conjunctivitis), leading to thick, woody (ligneous), inflamed growths. The growths usually appear yellow, white, or red in color. Ligneous conjunctivitis most often occurs on the inside of the eyelids. These growths can lead to tearing of the cornea, scarring, and vision loss. 

Other, less commonly affected areas include the inside of the mouth and gums, ears, upper and lower gastrointestinal tract, lungs, and female reproductive tract. The central nervous system (brain and spinal cord) and skin may also be affected.[4][5][3]
Last updated: 6/15/2016

How might type 1 plasminogen deficiency be treated?

The treatment options available for type 1 plasminogen deficiency are few. However, some cases of ligneous conjunctivitis, the most common disease manifestation, have been successfully treated using a combination of surgery and plasminogen administration. Surgery alone to remove the eye growths can be a temporary fix; however, irritation secondary to surgery can result in recurrence. Other therapies that have been utilized with a varying degree of success include: corticosteroids, immunosuppressants (Cyclosporine), blood thinners (heparin), alpha-chymotrypsin (digestive enzyme), plasma infusion (white blood cells), and anti-virals.[6][7]
Last updated: 6/16/2016

What causes type 1 plasminogen deficiency?

Type 1 plasminogen deficiency is caused by mutations in the PLG gene. This gene provides instructions for making a protein called plasminogen.[2][3] Enzymes called plasminogen activators convert plasminogen into the protein plasmin, whose function is to dissolve fibrin clots. Fibrin clots form scabs at a wound site, providing the framework for new tissue growth.[2] PLG mutations can decrease the amount of plasminogen that is produced, alter its function, or both. When the mutations affect plasminogen levels as well as the activity of the protein, type 1 plasminogen deficiency results.[2][3] A reduction in functional plasminogen results in less plasmin, which allows fibrin to buildup. The excess fibrin and the resulting inflammation of the tissue result in the inflamed woody growth characteristic of this condition.[2] 

Last updated: 6/13/2016

Is type 1 plasminogen deficiency inherited? If so, in what manner?

Type 1 plasminogen deficiency is inherited in an autosomal recessive manner. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell.[2] Affected people inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs and symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:
  • 25% (1 in 4) chance to be affected,
  • 50% (1 in 2) chance to be an unaffected carrier, like each parent, and 
  • 25% (1 in 4) chance to be unaffected and not be a carrier.
Last updated: 6/14/2016

References
Other Names for this Disease
  • Hypoplasminogenemia
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.