GENE REFERENCE / HGNC:9118

PMP22

peripheral myelin protein 22

protein-coding gene17p12Gene information

What does this gene do?

The PMP22 gene provides instructions for making a protein called peripheral myelin protein 22 (PMP22). This protein is found in the peripheral nervous system, which connects the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound.

The PMP22 protein is a component of myelin, a protective substance that covers nerves and promotes the efficient transmission of nerve impulses. The protein is produced primarily by specialized cells called Schwann cells that wrap around and insulate nerves. Within Schwann cells, PMP22 plays a crucial role in the development and maintenance of myelin. Studies suggest that the PMP22 protein is particularly important in protecting nerves from physical pressure, helping them restore their structure after being pinched or squeezed (compressed). Compression can interrupt nerve signaling, leading to the sensation commonly referred to as a limb "falling asleep." The ability of nerves to recover from normal, day-to-day compression, for example when sitting for long periods, keeps the limbs from constantly losing sensation. The PMP22 gene also plays a role in the growth of Schwann cells and the process by which cells mature to carry out specific functions (differentiation).

Before they become part of myelin, newly produced PMP22 proteins are processed and packaged in specialized cell structures called the endoplasmic reticulum and the Golgi apparatus. Completion of these processing and packaging steps is critical for proper myelin function.

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-04-19. Source review: 2018-10.

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
Charcot-Marie-Tooth disease type 1AMONDO:0007309 · Evaluated 2022-10-10	Autosomal dominant	DefinitiveCharcot-Marie-Tooth Disease Gene Curation Expert Panel
hereditary neuropathy with liability to pressure palsiesMONDO:0008087 · Evaluated 2024-07-08	Autosomal dominant	DefinitiveCharcot-Marie-Tooth Disease 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: 610
Submissions for variants in or overlapping this gene: 1,030
Submissions explicitly reporting this gene: 884
Alleles reported pathogenic / likely pathogenic: 137
VariationIDs with uncertain significance: 184
VariationIDs with conflicting classifications: 29

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 PMP22?

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 137 alleles in PMP22 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 PMP22.

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

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