GENE REFERENCE / HGNC:11957

MED12

mediator complex subunit 12

protein-coding geneXq13.1Gene information

What does this gene do?

The MED12 gene provides instructions for making a protein called mediator complex subunit 12. As its name suggests, this protein forms one part (subunit) of the mediator complex, which is a group of about 25 proteins that work together to regulate gene activity. The mediator complex physically links transcription factors, which are proteins that influence whether genes are turned on or off, with an enzyme called RNA polymerase II. Once transcription factors are attached, this enzyme initiates gene transcription, the process by which information stored in a gene's DNA is used to build proteins.

Researchers believe that the MED12 protein is involved in many aspects of early development, including the development of nerve cells (neurons) in the brain. The MED12 protein is part of several chemical signaling pathways within cells. These pathways help direct a broad range of cellular activities, such as cell growth, cell movement (migration), and the process by which cells mature to carry out specific functions (differentiation).

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-04-14. Source review: 2013-04.

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
MED12-related intellectual disability syndromeMONDO:0100000 · Evaluated 2025-10-15	X-linked	DefinitiveIntellectual Disability and Autism 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: 2,769
Submissions for variants in or overlapping this gene: 4,328
Submissions explicitly reporting this gene: 4,139
Alleles reported pathogenic / likely pathogenic: 98
VariationIDs with uncertain significance: 994
VariationIDs with conflicting classifications: 156

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 MED12?

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 98 alleles in MED12 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 MED12.

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

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