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CHMP1A
charged multivesicular body protein 1A
CHMP1A is located on the long (q) arm of chromosome 16, at band 16q24.3. Arm ratio per GRCh38 - banding schematic.
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Overview
CHMP1A (charged multivesicular body protein 1A) is a human gene located on chromosome 16 that encodes a protein participating in the endosomal sorting complexes required for transport (ESCRT) pathway. The ESCRT machinery comprises several multiprotein assemblies that collaborate to remodel cellular membranes and direct the sorting of membrane-associated proteins into specific cellular compartments.
The ESCRT-III complex, of which CHMP1A is a constituent, plays a central role in the final stages of multivesicular body formation, helping to sequester ubiquitinated cargo proteins into vesicles destined for degradation. This process is fundamental to cellular quality control, receptor downregulation, and the recycling of membrane components.
What the gene does
The protein encoded by CHMP1A functions as part of the ESCRT-III complex, a dynamic assembly that forms filamentous structures on membrane surfaces. These structures drive the invagination and scission of membrane necks during the formation of intralumenal vesicles within multivesicular bodies.
ESCRT-III components typically assemble transiently at sites where membrane deformation is required, including during endosomal maturation, cytokinetic abscission, and viral budding events. The CHMP1A protein contributes to the structural framework that enables these membrane-remodelling activities, working in coordination with other charged multivesicular body proteins to complete cargo sorting.
Through its participation in endosomal trafficking, CHMP1A indirectly influences cellular signalling pathways by controlling the availability and localisation of receptors at the plasma membrane. Proper function of the ESCRT pathway is essential for downregulating activated receptors and preventing aberrant signalling that could affect cell growth or differentiation.
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Chromosome location
CHMP1A is positioned on the long arm of chromosome 16 at band q24.3, designated cytogenetically as 16q24.3. This chromosomal region contains numerous genes involved in diverse cellular processes. The precise genomic coordinates and exon structure have been mapped through reference genome assemblies, though detailed structural annotations vary across databases.
Protein structure
Domain architecture has not been experimentally characterised in detail for this protein. CHMP1A belongs to the chromatin-modifying protein/charged multivesicular body protein family, members of which typically contain coiled-coil regions that mediate protein-protein interactions and enable assembly into higher-order structures on membrane surfaces. These structural features are thought to facilitate the dynamic polymerisation and membrane-binding activities characteristic of ESCRT-III components.
Key variants
Genetic variants in CHMP1A have been catalogued in public databases, though the clinical significance of most sequence changes remains uncertain. As with many genes involved in fundamental cellular processes, distinguishing pathogenic variants from benign polymorphisms requires careful assessment of functional impact and segregation data. Carrier screening panels do not currently include CHMP1A as a primary target gene.
Sample of pathogenic variants
2 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.28-13G>A | - | Pathogenic/Likely pathogenic | ★★☆☆ | Pontocerebellar hypoplasia type 8 |
c.19del | p.Gln7fs | 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
At present, CHMP1A is not definitively associated with any Mendelian disorders in clinical genetics databases. The gene's role in essential cellular machinery suggests that severe loss-of-function variants might be incompatible with normal development, though this remains speculative. Research into ESCRT pathway dysfunction continues to explore potential links to neurodegenerative and cellular stress-related phenotypes.
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 CHMP1A protein do in cells?
CHMP1A is part of the ESCRT-III complex, which helps reshape cellular membranes and sort proteins into compartments for degradation or recycling. This process is essential for controlling receptor signalling and maintaining cellular health.
Is CHMP1A included in NHS genetic testing panels?
CHMP1A does not currently appear on NHS Genomic Medicine Service gene panels. It is not part of routine carrier screening or diagnostic testing pathways for inherited conditions in the UK.
Are CHMP1A variants linked to specific medical conditions?
No definitive disease associations have been established for CHMP1A variants. The gene's role in fundamental cellular processes is recognised, but clear genotype-phenotype correlations have not been defined in clinical genetics literature.