GENE REFERENCE / HGNC:1785

CDKN1B

cyclin dependent kinase inhibitor 1B

protein-coding gene12p13.1Gene information

What does this gene do?

The CDKN1B gene provides instructions for making a protein called p27. This protein is found in cells and tissues throughout the body. Within cells, p27 is located primarily in the nucleus, where it plays a critical role in controlling cell growth and division. It helps regulate the cell cycle, which is the cell's way of replicating itself in an organized, step-by-step fashion. Specifically, p27 normally blocks cells from entering the phase of the cell cycle when DNA is copied (replicated) in preparation for cell division. By blocking cell cycle progression, p27 prevents cells from dividing too quickly or at the wrong time. Based on this function, p27 is described as a tumor suppressor protein. Studies suggest that p27 is also involved in controlling cell differentiation, which is the process by which cells mature to carry out specific functions.

Because p27 plays such a key role in controlling cell division, its activity is tightly regulated. Regulation can occur through modification of the p27 protein's structure, its interaction with other proteins, or its localization within the cell. For example, when p27 is held (sequestered) in the fluid that surrounds the nucleus (the cytoplasm) instead of being transported into the nucleus, the protein is unavailable to block cell cycle progression. Researchers believe that p27 may have other functions in the cytoplasm, but these functions have not been well described.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2013-08.

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.

Condition	Inheritance	Evidence
hereditary nonpolyposis colon cancerMONDO:0018630 · Evaluated 2017-06-08	Autosomal recessive	LimitedColon Cancer Gene Curation Expert Panel
multiple endocrine neoplasia type 4MONDO:0012552 · Evaluated 2018-12-21	Autosomal dominant	DefinitiveHereditary Cancer 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: 1,196
Submissions for variants in or overlapping this gene: 2,240
Submissions explicitly reporting this gene: 2,186
Alleles reported pathogenic / likely pathogenic: 128
VariationIDs with uncertain significance: 617
VariationIDs with conflicting classifications: 107

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 CDKN1B?

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 128 alleles in CDKN1B 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 CDKN1B.

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

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