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Genetics Library / Genes / PIK3CD

GENE REFERENCE / HGNC:8977

PIK3CD

phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta

protein-coding gene1p36.22Gene information

What does this gene do?

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 that contains the p110δ subunit, called PI3K delta, is 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.

PI3K delta functions as a kinase, which means that it 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.

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-08-16. Source review: 2023-08.

Related condition topics

MedlinePlus mentions this gene in the condition pages below. These links alone do not show that the gene causes a condition.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

ConditionInheritanceEvidence
immunodeficiency 14b, autosomal recessiveMONDO:0023655 · Evaluated 2022-04-19Autosomal recessiveDefinitiveAntibody Deficiencies Gene Curation Expert Panel
immunodeficiency 14MONDO:0014222 · Evaluated 2022-04-19Autosomal dominantDefinitiveAntibody Deficiencies Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles
1,137
Submissions for variants in or overlapping this gene
1,798
Submissions explicitly reporting this gene
1,708
Alleles reported pathogenic / likely pathogenic
37
VariationIDs with uncertain significance
436
VariationIDs with conflicting classifications
16

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about PIK3CD?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 37 alleles in PIK3CD reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in PIK3CD.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

Sources and dates

The source information on this page last changed on 2026-10-10.

HGNC Source details

Open source record ↗

Source release: Fri, 09 Oct 2026 13:40:45 GMT
Source record updated: 2023-01-20

SHA-256: e4cd9c6d7120051b80e5e61d2aeb98bd6a541ddd21f428a6eab922c11242e053

MedlinePlus Source details

Open source record ↗

Source release: Sat, 10 Oct 2026 05:16:07 GMT
Source publication: 2023-08-16
Source review: 2023-08

SHA-256: fdc8bd614310c12718379cef6569962e5d0e791cecabcc355b53a72816ac263a

ClinVar Source details

Open source record ↗

Source release: Sun, 04 Oct 2026 13:15:29 GMT

SHA-256: 126d9e5bded1d43c0380ac6684c86f9aab056d2ff2be93d743e408ed917ae558

ClinGen Source details

Open source record ↗

Source release: Sat, 10 Oct 2026 09:49:14 GMT

SHA-256: 5bbc9404c72cc21d80e36ea4c49380231755850af5c34064262adceb74881af6

About the library sources · Latest validated release · Record 51f79152abf1