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MSN
moesin
MSN is located on the long (q) arm of chromosome X, at band Xq12. Arm ratio per GRCh38 - banding schematic.
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Overview
MSN is located on the X chromosome at position Xq12 and encodes moesin, a cytoskeletal protein with important roles in maintaining cell structure and coordinating cellular responses. Moesin belongs to the ERM (ezrin-radixin-moesin) family of proteins, which share the ability to cross-link the plasma membrane with actin filaments beneath it.
Because MSN sits on the X chromosome, inheritance patterns can vary depending on the specific variant and whether it affects protein function. Males carry one X chromosome, whilst females carry two, which influences how genetic changes in MSN may be expressed. Research into MSN variants and their effects on human health is ongoing, with the gene drawing interest in studies of cell biology and developmental processes.
What the gene does
Moesin functions primarily as a structural and regulatory protein, organising the interface between the cell membrane and the cytoskeleton. The protein remains inactive until cellular signals trigger a conformational change, typically through phosphorylation, allowing it to bind both membrane proteins and actin filaments simultaneously. This dual binding capability enables moesin to stabilise membrane protrusions such as microvilli, which are finger-like extensions that increase the surface area of cells lining the intestine and kidney.
Beyond its structural role, moesin participates in signal transduction pathways that control cell movement, adhesion, and polarity. The protein helps organise receptor complexes at the cell surface, ensuring that signals from the external environment are efficiently transmitted to the cell interior. Moesin also contributes to the mechanics of cell division, helping to coordinate the distribution of cellular components during mitosis. Through these activities, moesin influences processes ranging from immune cell activation to the maintenance of epithelial barriers in organs throughout the body.
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Chromosome location
MSN is positioned on the long arm of the X chromosome at band q12, designated as Xq12. This chromosomal region contains numerous genes involved in cellular processes and development. The genomic structure of MSN and its precise exon count have been characterised through sequencing studies, though detailed annotation continues to evolve as research progresses. Being X-linked affects how variants in this gene may be inherited and expressed across generations.
Protein structure
Domain architecture has not been experimentally characterised in detail for this protein.
Key variants
Genetic variants in MSN include changes to the DNA sequence that may alter the moesin protein's structure or expression level. Some variants represent common differences in the population with no known health impact, whilst others may affect how the protein functions. Research into the clinical significance of specific MSN variants is ongoing, with studies examining how changes to moesin might influence cellular behaviour and contribute to disease processes.
Sample of pathogenic variants
10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.511C>T | p.Arg171Trp | Pathogenic | ★★☆☆ | Combined immunodeficiency due to moesin deficiency |
c.1174_1183dup | p.Glu395fs | Pathogenic | ★☆☆☆ | not provided |
c.1279C>T | p.Arg427Ter | Pathogenic | ★☆☆☆ | not provided |
c.1303C>T | p.Arg435Ter | Pathogenic | ★☆☆☆ | not provided |
c.1348C>T | p.Gln450Ter | Pathogenic | ★☆☆☆ | not provided |
c.1471dup | p.Ser491fs | Pathogenic | ★☆☆☆ | not provided |
c.49G>T | p.Glu17Ter | Pathogenic | ★☆☆☆ | not provided |
c.504G>A | p.Trp168Ter | Pathogenic | ★☆☆☆ | not provided |
c.585_586dup | p.Gln196fs | Pathogenic | ★☆☆☆ | not provided |
c.586C>T | p.Gln196Ter | Pathogenic | ★☆☆☆ | not provided |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Current understanding of MSN's role in human disease is still developing. Because moesin performs essential functions in many cell types, researchers are investigating whether certain variants might contribute to conditions affecting tissues where the protein is highly active, such as the intestinal lining, kidney tubules, and immune cells. The gene's position on the X chromosome adds complexity to genotype-phenotype correlations, as the same variant may have different effects in males and females.
No disease links recorded for this gene in our reference set.
UK clinical status
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Frequently asked questions
What does the MSN gene do?
MSN provides instructions for making moesin, a protein that connects the cell membrane to the internal structural framework. This connection helps cells maintain their shape, move, and respond to signals from their surroundings.
Why is MSN located on the X chromosome significant?
Because MSN is on the X chromosome, males have only one copy whilst females have two. This difference can influence how genetic variants in MSN affect health, as males lack a second copy that might compensate for a changed gene.
Are there clinical tests available for MSN variants?
MSN is not currently included in standard NHS clinical gene panels, though research laboratories may analyse this gene as part of broader genetic studies. Testing availability depends on the specific clinical question and the evidence linking MSN variants to particular conditions.