Individuals with a complement deficiency can have clinical problems that are a result of the role that the specific complement protein plays in the normal function of the human body.

NEMO deficiency syndrome is a complex disease caused by genetic variants in the X-linked NEMO gene (also known as IKK gamma or IKKG).

Hyper IgM syndromes (HIGM) are characterized by decreased levels of immunoglobulin G (IgG) in the blood and normal or elevated levels of immunoglobulin M (IgM). 

DiGeorge syndrome, most frequently caused by a deletion at 22q11.2, is a PI caused by abnormal migration and development of certain cells and tissues during fetal development.

Congenital athymia is an ultra-rare condition in which children are born without a thymus, causing severe immunodeficiency and immune dysregulation.

Common variable immune deficiency (CVID), previously known as adult-onset hypogammaglobulinemia, is one of the most frequently diagnosed primary immunodeficiencies. It is characterized by low levels of serum antibodies, which cause an increased susceptibility to infection.

Chronic granulomatous disease (CGD) is an inherited disease in which the body’s cells that eat invaders (also called phagocytes) do not make hydrogen peroxide and other chemicals. These chemicals are needed to kill certain bacteria and fungi.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), also known as autoimmune polyglandular syndrome type-1 (APS-1) or polyglandular autoimmune (PGA) syndrome type-1, is a primary immunodeficiency disease caused by variants in the autoimmune regulator (AIRE) gene.

 

Activated PI3K delta syndrome (APDS) is a rare primary immunodeficiency (PI) that is often misdiagnosed as CVID or another antibody deficiency.