Activated phosphoinositide 3-kinase delta syndrome

Activated phosphoinositide 3-kinase delta syndrome is a rare primary immunodeficiency and inborn error of immunity affecting both humoral and cellular components of the immune system Pathophysiologically, this results in progressive T- and B-cell dysregulation and lymphopenia, clinically manifesting in childhood as recurrent sinopulmonary and viral infections, bronchiectasis, nonmalignant lymphoproliferation, autoimmunity, and a heightened lifetime risk of lymphoid malignancies

Activated phosphoinositide 3-kinase delta syndrome is a rare primary immunodeficiency and inborn error of immunity affecting both humoral and cellular components of the immune system Caused by autosomal dominant gain-of-function variants in *PIK3CD* or loss-of-function variants in *PIK3R1*, the disorder leads to constitutive hyperactivation of the PI3K-Akt-mTOR signaling pathway in leukocytes

Caused by autosomal dominant gain-of-function variants in *PIK3CD* or loss-of-function variants in *PIK3R1*, the disorder leads to constitutive hyperactivation of the PI3K-Akt-mTOR signaling pathway in leukocytes

Pathophysiologically, this results in progressive T- and B-cell dysregulation and lymphopenia, clinically manifesting in childhood as recurrent sinopulmonary and viral infections, bronchiectasis, nonmalignant lymphoproliferation, autoimmunity, and a heightened lifetime risk of lymphoid malignancies