GENE REFERENCE / HGNC:2482

CSTB

cystatin B

protein-coding gene21q22.3Gene information

What does this gene do?

The CSTB gene provides instructions for making a protein called cystatin B. This protein reduces the activity of (inhibits) enzymes called cathepsins. Cathepsins help break down certain proteins in the lysosomes, which are compartments in the cell that digest and recycle different types of molecules. Cystatin B may help protect the cells' proteins from cathepsins that leak out of the lysosomes.

Cystatin B is also believed to play a role in the development, movement, and communication of nerve cells. In addition, cystatin B helps control the nervous system's immune response (inflammation) and protects cells from harm caused by unstable molecules in the body (oxidative stress).

Source: MedlinePlus, National Library of Medicine. Source publication: 2024-03-27. Source review: 2024-03.

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
Unverricht-Lundborg syndromeMONDO:0009698 · Evaluated 2020-06-16	Autosomal recessive	DefinitiveEpilepsy Gene Curation Expert Panel
genetic developmental and epileptic encephalopathyMONDO:0100062 · Evaluated 2020-12-01	Autosomal recessive	ModerateEpilepsy 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: 295
Submissions for variants in or overlapping this gene: 469
Submissions explicitly reporting this gene: 352
Alleles reported pathogenic / likely pathogenic: 23
VariationIDs with uncertain significance: 90
VariationIDs with conflicting classifications: 12

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 CSTB?

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 23 alleles in CSTB 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 CSTB.

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

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