GJB2 rs80338943: Understanding the 167delT Variant
The rs80338943 variant, also known as 167delT, is a single-base deletion in the GJB2 gene. It is primarily recognized as a carrier variant associated with nonsyndromic recessive hearing impairment when inherited in a biallelic state.
What each genotype means
Typical GJB2 profile
This genotype represents the common, non-deleted sequence at this position in the GJB2 gene. It is not associated with the specific hearing impairment linked to the c.167delT variant.
This is the most common genotype observed across all global populations.
Carrier of hearing loss variant
You carry one copy of the c.167delT deletion, which is a known pathogenic variant in the GJB2 gene. As this condition is inherited in an autosomal recessive manner, carriers typically do not experience hearing loss, but should be aware of the potential for passing this variant to offspring.
This variant is found as a founder mutation in Ashkenazi Jewish populations, with an allele frequency of approximately 0.02.
What is the rs80338943 Variant?
The variant rs80338943, commonly referred to in scientific literature as 167delT, is a specific genetic alteration located within the GJB2 gene on chromosome 13. This variant is characterized by the deletion of a single thymine nucleotide at position 167 of the coding sequence. Because this deletion occurs within the protein-coding region, it causes a frameshift, which typically leads to the production of a truncated, non-functional protein. In the context of human genetics, this variant is classified as a pathogenic allele when present in a homozygous state or in combination with another pathogenic GJB2 variant. It is one of several well-documented mutations in this gene that have been studied extensively due to their significant impact on auditory function. Understanding this variant requires looking at the specific location on the gene and how that change disrupts the normal biological instructions for building essential proteins in the inner ear.
The Role of the GJB2 Gene
The GJB2 gene provides instructions for making a protein called connexin 26. This protein is a member of the connexin family, which forms gap junctions—specialized channels that allow for the direct exchange of ions, nutrients, and signaling molecules between adjacent cells. In the inner ear, connexin 26 is critical for maintaining the chemical environment necessary for the hair cells to function properly. These hair cells are responsible for converting sound waves into electrical signals that the brain interprets as sound. When GJB2 mutations occur, the resulting connexin 26 protein may be absent or dysfunctional, disrupting the flow of potassium ions in the cochlea. This disruption prevents the hair cells from effectively transmitting signals, which manifests as sensorineural hearing loss. Because the gene is essential for this delicate biological process, even small changes like the 167delT deletion can have profound effects on an individual's ability to hear.
Research and Clinical Associations
Research has established a strong association between biallelic GJB2 variants and nonsyndromic recessive sensorineural hearing loss. The 167delT variant is specifically noted for its prevalence in the Ashkenazi Jewish population. Studies have shown that individuals who inherit two copies of a pathogenic GJB2 variant, or one copy of 167delT paired with another pathogenic mutation, are at a significantly higher risk for hearing impairment. While the evidence linking this variant to hearing loss is robust, the clinical presentation can vary, and not every individual with a specific genotype will experience the same degree of hearing loss. It is important to note that while GJB2 variants account for a large portion of hereditary hearing loss cases, they do not explain all instances. Genetic testing and counseling are often recommended for families with a history of hearing loss to better understand the specific genetic factors involved and the potential for inheritance.
Population Frequency and Distribution
The frequency of the rs80338943 variant varies significantly across different ethnic and ancestral groups. It is most frequently identified in individuals of Ashkenazi Jewish descent, where it is recognized as a common carrier variant. Population databases, such as gnomAD, provide insights into these frequencies, showing that the allele is present at a higher rate in this specific population compared to others. In many other global populations, this specific deletion is rare or absent. These differences in frequency are often attributed to founder effects, where a variant becomes more common in a population due to the limited number of ancestors who carried the trait. Because of this, genetic screening for GJB2 variants is often prioritized in clinical settings for individuals of Ashkenazi Jewish heritage who are seeking information about their carrier status for recessive hearing loss conditions.
Navigating Genetic Information
If you have received information about your status regarding the rs80338943 variant, it is important to understand what this means in a broader context. Being a carrier for a recessive condition typically means you have one copy of the variant and one normal copy of the gene, which usually does not result in hearing loss. However, if both parents are carriers, there is a statistical possibility of passing the condition to their children. This information should not be used for self-diagnosis or to make medical decisions without professional guidance. If you are concerned about your genetic status or family history, the most appropriate step is to consult with a certified genetic counselor or a medical geneticist. These professionals can help interpret your results, explain the implications for your family, and discuss the availability of diagnostic testing. Always rely on qualified healthcare providers to translate genetic data into actionable health information.
How common is this variant?
The rs80338943 variant is most commonly found in the Ashkenazi Jewish population, with an allele frequency of approximately 0.02 in gnomAD data.
Frequently asked questions
What does it mean to be a carrier of GJB2?
Being a carrier means you have one copy of a pathogenic GJB2 variant and one normal copy. Carriers typically do not experience hearing loss themselves but can pass the variant to their children.
Is GJB2-related hearing loss treatable?
While there is no cure for the genetic cause of GJB2-related hearing loss, various interventions such as hearing aids and cochlear implants are commonly used to manage the condition and improve auditory function.
Should I get tested for the 167delT variant?
Genetic testing is a personal decision often made in consultation with a healthcare provider. It is typically considered by individuals with a family history of hearing loss or those planning a family who want to understand their carrier status.
Does having the 167delT variant guarantee hearing loss?
No, having the variant does not guarantee hearing loss. The condition is recessive, meaning it generally requires two pathogenic variants to manifest, and even then, the severity can vary between individuals.
Sources & further reading
Educational information only, last refreshed 9/24/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Also known as 35delG, this frameshift mutation is a major cause of autosomal recessive nonsyndromic sensorineural hearing loss.
Pathogenic nonsense variant (p.Trp24Ter) in GJB2, representing one of the major causative alleles for autosomal recessive non-syndromic hearing loss in Mediterranean and South Asian groups.
This variant is associated with autosomal recessive nonsyndromic hearing loss.
Missense variant (p.Arg127His) in the GJB2 gene. While often reported in individuals with hearing loss, it is frequently classified as benign or likely benign in clinical databases when found in isolation, as it is common in the general population.
Frameshift deletion (c.235delC) conferring carrier status for autosomal recessive non-syndromic sensorineural hearing loss.
Common East Asian frameshift mutation (c.235delC) causing severe truncation of Connexin 26, a major cause of autosomal recessive nonsyndromic hearing loss.