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Reviewed July 2014

What is the official name of the PIK3CD gene?

The official name of this gene is “phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta.”

PIK3CD is the gene's official symbol. The PIK3CD gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the PIK3CD gene?

The PIK3CD gene provides instructions for making the p110 delta (p110δ) protein, which is one piece (subunit) of an enzyme called phosphatidylinositol 3-kinase (PI3K). The version of PI3K containing the p110δ subunit, called PI3K-delta, is specifically found in white blood cells, including immune system cells (lymphocytes) called B cells and T cells. These cells recognize and attack foreign invaders, such as viruses and bacteria, to prevent infection.

Like other kinases, PI3K-delta adds a cluster of oxygen and phosphorus atoms (a phosphate group) to other proteins through a process called phosphorylation. PI3K-delta phosphorylates certain signaling molecules, which triggers a series of additional reactions that transmit chemical signals within cells. In lymphocytes, PI3K-delta signaling is important for many cell activities, including cell growth and division (proliferation) and maturation (differentiation). PI3K-delta helps direct B cells and T cells to differentiate into different types, each of which has a distinct function in the immune system.

How are changes in the PIK3CD gene related to health conditions?

activated PI3K-delta syndrome - caused by mutations in the PIK3CD gene

At least four mutations in the PIK3CD gene have been found to cause a form of immunodeficiency called activated PI3K-delta syndrome. Immunodeficiencies are conditions in which the immune system is not able to protect the body effectively from foreign invaders such as bacteria and viruses. People with activated PI3K-delta syndrome typically have recurrent bacterial infections of the respiratory tract and chronic viral infections.

The PIK3CD gene mutations involved in activated PI3K-delta syndrome change single protein building blocks (amino acids) in the p110δ protein; the most common mutation replaces the amino acid glutamic acid with the amino acid lysine at position 1021 of the protein (written as Glu1021Lys or E1021K). A PI3K-delta enzyme containing the altered p110δ subunit is abnormally turned on (activated). Studies indicate that this overactive signaling causes T cells to mature and die too quickly. The excess signaling also blocks maturation of B cells at an early stage; the immature B cells cannot respond to foreign invaders and likely self-destruct. Lack of T cells and B cells makes it difficult for people with this disorder to fight off bacterial and viral infections. Overactivation of PI3K-delta signaling can also stimulate abnormal proliferation of lymphocytes, and accumulation of these cells can lead to enlarged lymph nodes (lymphadenopathy). Activated PI3K-delta syndrome also increases the risk of developing a form of cancer called B-cell lymphoma.

Where is the PIK3CD gene located?

Cytogenetic Location: 1p36.2

Molecular Location on chromosome 1: base pairs 9,629,889 to 9,729,114

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The PIK3CD gene is located on the short (p) arm of chromosome 1 at position 36.2.

The PIK3CD gene is located on the short (p) arm of chromosome 1 at position 36.2.

More precisely, the PIK3CD gene is located from base pair 9,629,889 to base pair 9,729,114 on chromosome 1.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about PIK3CD?

You and your healthcare professional may find the following resources about PIK3CD helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the PIK3CD gene or gene products?

  • APDS
  • IMD14
  • p110D
  • P110DELTA
  • phosphatidylinositol-4,5-bisphosphate 3-kinase 110 kDa catalytic subunit delta
  • phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit delta
  • phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta isoform
  • phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta isoform
  • phosphoinositide-3-kinase C
  • phosphoinositide-3-kinase, catalytic, delta polypeptide variant p37delta
  • PI3K
  • PI3Kdelta
  • PI3-kinase p110 subunit delta
  • ptdIns-3-kinase subunit p110-delta

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding PIK3CD?

acids ; amino acid ; bacteria ; cancer ; catalytic ; cell ; chronic ; differentiation ; enzyme ; gene ; glutamic acid ; immune system ; immunodeficiency ; infection ; kinase ; lymph ; lymphoma ; lysine ; mutation ; oxygen ; phosphate ; phosphorus ; phosphorylation ; proliferation ; protein ; respiratory ; stage ; subunit ; syndrome ; white blood cells

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (8 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: July 2014
Published: February 8, 2016