Primary Immunodeficiency (PI) is an umbrella term for over 350 genetic defects and disorders of the immune system recognized by the World Health Organization. Together they affect approximately 29,000 Canadians. Primary Immunodeficiency is not considered a rare disease as a category, but each individual form of PI is rare.
There are currently 3 names in this directory beginning with the letter L.
Leucocyte Adhension Deficiency, (LAD)
Leukocyte adhesion deficiency (LAD) is a primary immunodeficiency disorder that involves phagocytic cell defects. Inheritance is autosomal recessive.
LAD is caused by deficiency of adhesive glycoproteins on the surfaces of WBCs; these glycoproteins facilitate cellular interactions, cell attachment to blood vessel walls, cell movement, and interaction with complement fragments. Deficiencies impair the ability of granulocytes (and lymphocytes) to migrate out of the intravascular compartment, to engage in cytotoxic reactions, and to phagocytose bacteria. Severity of disease correlates with degree of deficiency.
Leukocyte Adhesion Deficiency
Individuals with LAD type 1 are susceptible to severe bacterial and fungal infections from birth. Symptoms of LAD type 1 are bacterial and fungal infections affecting the skin and mucous membranes; severe gingivitis and periodontitis leading to tooth loss; and wounds that are slow to heal. Leukocyte Adhesion Deficiency type 1 is a serious condition that can be life-limiting.
LAD1 is by far the most common cause of leukocyte adhesion deficiency and it is usually corrected by bone marrow transplantation. There are milder forms of LAD1 that can be treated with antibiotics alone. LAD type 2 occurs with mutations in an enzyme that attaches fucose (a type of sugar) to proteins. LAD 2 can be treated by eating large quantities of fucose. LAD type 3 is caused by mutations in a gene called FERMT3.
Credits: Immune Deficiency Foundation, Genetics Home Reference
Leukocyte Adhesion Deficiency Syndromes
Leukocyte adhesions deficiency (LAD) syndromes are a group of rare disorders affecting the immune system. LAD syndromes are characterized by defects affecting how white blood cells (leukocytes) respond and travel to the site of a wound or infection. Three distinct types of leukocyte adhesion syndrome have been identified. The specific symptoms and the severity of LAD syndromes vary from one person to another.
All affected individuals develop an increased susceptibility to developing recurrent bacterial and fungal infections. Additional symptoms may occur depending upon the specific subtype present. LAD syndromes are caused by mutations of specific genes that contain instructions for creating certain proteins that are necessary for white blood cells to travel from the bloodstream to the site of an infection or inflammation. Credit: NORD.