<unk> es are disorders in which part of the body's immune system is missing or does not function normally. To be considered a<unk>  <unk> , the cause of the immune deficiency must not be secondary in nature (i.e., caused by other disease, drug treatment, or environmental exposure to toxins). Most<unk> es are genetic disorders; the majority are diagnosed in children under the age of one, although milder forms may not be recognized until adulthood. While there are over 430 recognized<unk> s as of 2019, most are very rare. About 1 in 500 people in the United States are born with a<unk> . Immune deficiencies can result in persistent or recurring infections, auto-inflammatory disorders, tumors, and disorders of various organs. There are currently limited treatments available for these conditions; most are specific to a particular type of<unk> . Research is currently evaluating the use of stem cell transplants (HSCT) and experimental gene therapies as avenues for treatment in limited subsets of<unk> s.
Primary immunodeficiency
Combined immunodeficiencies
Severe combined immunodeficiency
Selective immunoglobulin A deficiency
Common variable immunodeficiency
IgG deficiency
X-linked agammaglobulinemia
Adult-onset immunodeficiency syndrome