TECTB (tectorin beta) is a major non-collagenous structural component of the tectorial membrane (TM), a specialized extracellular matrix overlying the cochlear sensory epithelium 1. The TM is essential for sound transduction, as sound-induced hair cell movement relative to the TM deflects stereocilia bundles and generates electrical signals [UniProt]. TECTB contains a zona pellucida (ZP) domain with eight conserved cysteines critical for proper protein folding and matrix assembly 1. The protein functions primarily in TM structural integrity; TECTB interacts with alpha-tectorin (TECTA) and other matrix proteins to form the striated-sheet matrix that embeds collagen fibrils 2. TECTB is essential for normal hearing development, as mutations cause hearing loss through disrupted TM morphology. A missense variant (p.Cys225Tyr) causes autosomal dominant non-syndromic hearing loss, with homozygous animals exhibiting severe hearing loss and TM disorganization, while heterozygotes show increased susceptibility to noise-induced hearing loss 1. Additionally, TECTB levels are regulated by hepsin-mediated proteolytic processing during TM development 3. TECTB is transcriptionally downregulated in blood associated with comorbid psychopathology, though the neurobiological significance remains unclear 4.