Strong Genetic

Pendred Syndrome / DFNB4 Hearing Loss

Name: Pendred Syndrome / DFNB4 Hearing Loss
Creator: Realised
Published: 2026-03-01

GeneSLC26A4rsIDrs111033253, rs111033256, rs111033259, rs36039748, rs111033258, rs111033260InheritanceAutosomal recessiveCarrier frequency~1 in 100 general population (higher in East Asian populations)SystemCarrier Screening

Summary

Pendred syndrome is a condition that combines hearing loss with thyroid enlargement (goitre). The SLC26A4 gene encodes pendrin, an anion transporter that plays critical roles in the inner ear and thyroid. Two distinct conditions arise from variants in this gene — Pendred syndrome (hearing loss plus goitre) and DFNB4 (hearing loss without thyroid involvement). The same gene, different clinical presentations.

Practical takeaway

This matters when planning children. With a carrier frequency of approximately 1 in 100 in the general population (and higher in East Asian populations where H723R is common), partner carrier testing is a reasonable consideration. A carrier test through a GP or genetic counselling service can determine your partner's status. If you are both carriers, a genetic counsellor can discuss the hearing loss spectrum, the role of early intervention (hearing aids or cochlear implants), and thyroid monitoring. The reassuring context: hearing loss is the primary manifestation, cochlear implants are highly effective, and thyroid issues are typically mild and manageable. Realised does not calculate reproductive risk or advise on reproductive decisions.

Evidence detail

What Carrier Status Means For You

You are not affected. One working copy of SLC26A4 produces sufficient pendrin for normal inner ear and thyroid function. Your hearing and thyroid are unaffected by carrier status. This becomes relevant if your partner also carries an SLC26A4 variant. In that case, each child has a 25% chance of having Pendred syndrome or DFNB4, a 50% chance of being an unaffected carrier, and a 25% chance of inheriting neither variant.

Population Context

SLC26A4 variants occur worldwide with notable population-specific patterns. The H723R variant is particularly common in East Asian populations (Japanese, Korean, Chinese) and is one of the most common causes of hereditary hearing loss in these populations. European populations carry a more diverse set of variants. The condition was first described by Vaughan Pendred in 1896 in an Irish family with deafness and goitre. Carrier rates are broadly similar across populations, though specific variant frequencies differ substantially.

Limitations

23andMe tests 6 of over 400 known pathogenic SLC26A4 variants. The tested panel includes some of the most common variants across European and East Asian populations, but the extreme genetic heterogeneity means most pathogenic variants are not captured. A "not detected" result provides only partial reduction in carrier risk. Comprehensive carrier screening through a clinical laboratory, including full gene sequencing, is recommended if a partner is a known carrier, if there is family history of hearing loss, or if more definitive testing is desired.

Sources (6)

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