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 M.
Mannan-Binding Lectin Deficiency, (MBL)
Mannose-binding lectin (MBL) deficiency is a condition that affects the immune system. It is a fairly common condition, affecting approximately 5–30 people in every 100. People with this condition have low levels of an immune system protein called mannose-binding lectin in their blood. People with MBL deficiency may be prone to recurrent infections, including infections of the upper respiratory tract and other body systems. Sometimes those affected may also contract more serious infections, such as pneumonia and meningitis. The exact symptoms caused by infections vary in frequency and severity, depending on the type of infection. Credit: Primary Immunodeficiency UK.
MHC Class II Deficiency
MHC Class II deficiency (also known as bare lymphocyte syndrome type II) is a rare primary immunodeficiency disorder inherited in an autosomal recessive fashion resulting from the absence of MHC class II molecules on the surface of immune cells. Credit: IPOPI
MyD88 Deficiency
MyD88 (myeloid differentiation primary response protein 88) is a protein that allows the innate immune cell to function as normal. MyD88 deficiency is an inherited disorder where individuals suffer from recurrent and severe pyogenic (produces pus) bacterial infections. While individuals are susceptible to infections with S. pneumoniae, S. aureus, and P. aeruginosa, their immune systems could resist all other forms of bacteria, viruses, fungi, and parasites.
It's been observed that the susceptibility to infection in general improved with age. The number of infections are reduced approximately around the age of 10. The estimated frequency of MyD88 Deficiency is unknown.
Credits: Immune Deficiency Foundation, Genetics Home Reference