STRC Research

STRC Hearing Loss

5 min read

STRC Hearing Loss

TL;DR: Misha’s diagnosis. STRC gene = missing stereocilin → cochlear amplifier fails → 40-60 dB loss. Hair cells remain alive (not dead) → gene therapy is viable. Regeneron AAV.104 in preclinical for STRC. Estimated 10-year window. VUS on allele 2 reclassified to Likely Pathogenic (2026-03-16).

STRC-related hearing loss (DFNB16) is the 2nd most common hereditary hearing loss. Egor’s son Misha (born Aug 5, 2021) has this diagnosis.

The Story Behind the Research

Michael is 4. He doesn’t hear well. Two broken copies of the STRC gene. One confirmed pathogenic. The other was labeled “Variant of Uncertain Significance.” Three words that block him from gene therapy trials.

Egor is not a geneticist. He builds websites, shoots video, and does AI education. He has an AI agent (OpenClaw + Claude Opus 4.6) that can actually do things: download files, search databases, run code. One question led to reclassification evidence. Then conservation analysis. Then a hypothesis about fitting the gene into a single therapy vector. Then six structural experiments. Then three emails to the scientists who pioneered this research. One responded overnight. By day three, there was a new hypothesis the researchers hadn’t published yet.

Science shouldn’t be locked behind jargon. All research is documented at strc.egor.lol. OpenClaw is free and open source. Claude API cost: roughly $50-100 for a project like this.

The Science

  • Gene: STRC encodes stereocilin protein (1,775 amino acids, UniProt Q7RTU9)
  • Function: scaffolding for outer hair cell (OHC) stereocilia bundles + anchoring to tectorial membrane
  • When broken: cochlear amplifier fails (up to 60 dB amplification lost); stereocilia cannot form horizontal top connectors or attach to tectorial membrane
  • Key insight: hair cells remain ALIVE. They just lack the protein. This is why gene therapy can work — the target cells exist and are waiting.

Prognosis

  • Typically mild-to-moderate (40-50 dB SNHL)
  • Generally STABLE over lifetime (doesn’t get worse in most cases)
  • Non-syndromic (no other health issues)
  • Hearing aids highly effective for current management

Son’s Genotype

  • Allele 1: 98 kb deletion (STRC + CATSPER2) — confirmed pathogenic (paternal, MLPA confirmed)
  • Allele 2: c.4976A>C p.(Glu1659Ala) — Likely Pathogenic (reclassified 2026-03-16; was VUS)
  • WES report: Hong Kong Children’s Hospital (Lab No: 23C7500174, December 2022)
  • Molecular diagnosis confirmed: biallelic pathogenic STRC = DFNB16

Gene Therapy Timeline

  • 2022-2025: OTOF gene therapy restored hearing in dozens of deaf children (Regeneron AK-OTOF, different gene, proves the approach)
  • 2026: Iranfar et al. published dual-vector AAV restoring hearing in STRC-deficient mice (Science Advances, PMC12784207)
  • Preclinical: Regeneron AAV.104 program for STRC specifically
  • Advantage for gene therapy: OHCs do not divide (post-mitotic) → gene therapy effect is permanent
  • Challenge: STRC gene (5,325 bp) exceeds single-AAV limit → dual-vector required (unless mini-STRC approach works)

Key Research Metrics (from Analysis)

MetricValueMeaning
AlphaMissense score0.9016Likely Pathogenic (threshold: 0.564)
AlphaFold pLDDT at pos 165995.69Very high confidence structure
REVEL score0.65Predicted deleterious
Evolutionary conservation9/9 mammals100% conserved, ~80 million years

ACMG Classification Summary

  • PM2_Supporting: Absent from gnomAD (0/251,000+ alleles)
  • PM3 (Moderate): Found in trans with confirmed pathogenic deletion
  • PP1_Supporting: 100% conservation across 9 mammals (PEIFTEIGTIAAG motif)
  • PP3_Moderate: AlphaMissense 0.9016 + REVEL 0.65 concordant (Pejaver 2022 threshold)
  • Result: 2 Moderate + 2 Supporting = Likely Pathogenic

Key People in STRC Research

  • Jeffrey Holt (Harvard Medical School) — responded to Egor’s email; asked to share with research team
  • Saaid Safieddine (Institut Pasteur, Paris) — letter sent
  • Yilai Shu (Fudan University, Shanghai) — China trials, letter sent
  • Iranfar et al. — first STRC mouse gene therapy (Science Advances 2026)
  • Regeneron — AAV.104 preclinical program

Research Files

Retrieval Contexts

When researching gene therapy timelines for hearing loss — this note has the current state of STRC-specific programs and the broader OTOF proof-of-concept. When making decisions about Misha’s education or audiological care — the prognosis data and genotype details are here. When evaluating cochlear implant vs hearing aid trade-offs for STRC specifically — hair cells being alive changes the calculus entirely.

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