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PJVK
pejvakin
PJVK is located on the long (q) arm of chromosome 2, at band 2q31.2. Arm ratio per GRCh38 - banding schematic.
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Overview
PJVK encodes pejvakin, a protein named after its discoverers' contributions to understanding genetic hearing loss. This gene is expressed predominantly in the inner ear, where it supports the function of sensory hair cells and auditory neurons. Pathogenic variants in PJVK have been identified as a cause of inherited hearing loss, reflecting the protein's specialised role in auditory physiology. While PJVK-related hearing loss accounts for a small proportion of genetic deafness cases overall, understanding this gene has contributed to broader insights into the molecular mechanisms underlying auditory function. Research into pejvakin continues to inform genetic testing strategies for individuals and families affected by non-syndromic hearing impairment.
What the gene does
Pejvakin is thought to function within the auditory pathway, supporting the survival and proper functioning of cells required for hearing. Evidence suggests the protein may be involved in maintaining the health of auditory neurons and sensory hair cells, which convert sound vibrations into electrical signals the brain can interpret. The precise molecular mechanisms through which pejvakin operates remain an active area of investigation. Some research indicates the protein may play a role in protecting auditory cells from oxidative stress or supporting intracellular signalling pathways critical for auditory neuron development. Pejvakin is highly expressed in the cochlea, the spiral-shaped structure in the inner ear responsible for detecting sound. The protein's localisation and expression pattern underscore its specialised contribution to hearing function rather than broader cellular processes.
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Chromosome location
PJVK is located on the long arm of chromosome 2 at position 31.2, designated as 2q31.2. The gene spans genomic DNA that encodes a relatively small protein. Structural details regarding the number of exons and precise transcript organisation have been characterised through genome annotation efforts, though the gene's modest size reflects its highly specialised auditory function rather than involvement in multiple tissue systems.
Protein structure
Domain architecture has not been experimentally characterised in detail for this protein. Pejvakin is a 352-amino-acid protein whose three-dimensional structure and functional domains have not been extensively mapped through crystallography or other structural biology techniques. The absence of well-defined conserved domains in public protein databases suggests pejvakin may represent a relatively unique protein with specialised evolutionary adaptations for auditory system function. Further structural studies will be required to elucidate how the protein's sequence translates into its functional role within auditory cells.
Key variants
Pathogenic variants in PJVK have been documented in families with inherited hearing loss. The variant spectrum includes changes predicted to disrupt normal protein production or function, such as frameshift and nonsense variants that lead to truncated or absent pejvakin. Missense variants affecting critical residues have also been reported. The mode of inheritance for PJVK-related hearing loss can vary, with both recessive and, in some instances, digenic patterns observed, reflecting genetic complexity in auditory disorders.
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.1028G>C | p.Cys343Ser | Pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
c.131_134del | p.Phe44fs | Pathogenic | ★★☆☆ | not provided |
c.274C>T | p.Arg92Ter | Pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
c.406C>T | p.Arg136Ter | Pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
c.420del | p.Phe140fs | Pathogenic/Likely pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
c.490C>T | p.Arg164Ter | Pathogenic/Likely pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
c.499C>T | p.Arg167Ter | Pathogenic/Likely pathogenic | ★★☆☆ | Rare genetic deafness |
c.532C>T | p.Arg178Ter | Pathogenic/Likely pathogenic | ★★☆☆ | not provided |
c.547C>T | p.Arg183Trp | Pathogenic/Likely pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
c.823dup | p.Ser275fs | Pathogenic/Likely pathogenic | ★★☆☆ | Autosomal recessive nonsyndromic hearing loss 59 |
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
Variants in PJVK are associated with hereditary forms of hearing loss, typically non-syndromic in nature, meaning hearing impairment occurs without other major medical features. The onset and severity of hearing loss can vary among affected individuals, ranging from congenital profound deafness to later-onset progressive impairment. The contribution of PJVK variants to the overall landscape of genetic hearing loss is recognised in specialised genetic testing panels that evaluate multiple hearing-loss genes simultaneously, allowing for comprehensive genetic diagnosis in individuals with unexplained auditory impairment.
No disease links recorded for this gene in our reference set.
UK clinical status
Frequently asked questions
What does the PJVK gene do?
PJVK encodes pejvakin, a protein expressed in the inner ear that supports the function and survival of auditory neurons and sensory hair cells. These cells are essential for converting sound into signals the brain can interpret, making pejvakin critical for normal hearing.
How is PJVK-related hearing loss inherited?
PJVK-related hearing loss can follow different inheritance patterns. In many cases, it is inherited in an autosomal recessive manner, meaning two altered copies of the gene are required for hearing impairment to occur. Genetic counselling can clarify inheritance risks for individual families.
Can PJVK variants cause hearing loss later in life?
Yes, the onset and progression of PJVK-related hearing loss can vary. While some individuals experience congenital hearing impairment present from birth, others may develop progressive hearing loss that worsens over time, highlighting the variable expressivity of pathogenic variants in this gene.