# First Whole-Genome Sequencing Analysis of Tracheobronchopathia Osteochondroplastica with Critical Vocal Cord Involvement: Proposing a Novel Pathophysiological Model

## TL;DR

This paper reports the first whole-genome sequencing of a rare airway disease with vocal cord involvement, revealing genetic factors linked to airway calcification and proposing a new disease model.

## Contribution

The first whole-genome sequencing analysis of tracheobronchopathia osteochondroplastica with vocal cord involvement, proposing a novel pathophysiological model.

## Key findings

- Whole-genome sequencing identified 766 germline mutations and candidate genes related to calcification and inflammation.
- The study proposes a model where systemic genetic factors interact with local immune and fibroblast activity to cause airway calcification.
- Despite systemic mutations, calcification was restricted to the airway, suggesting localized pathogenic mechanisms.

## Abstract

Background: Tracheobronchopathia osteochondroplastica (TO) is a rare benign disorder characterized by submucosal cartilaginous and osseous nodules of the tracheobronchial tree, typically sparing the posterior membranous wall. Involvement of the vocal cords is exceedingly rare and may result in critical airway obstruction. The underlying genetic and molecular mechanisms of TO remain largely unexplored. Case presentation: We report a rare case of TO extending from the vocal cords to the bronchi in a 76-year-old man who initially presented with pneumonia and later developed acute respiratory failure due to severe airway narrowing, necessitating emergency tracheostomy. Bronchoscopy and computed tomography revealed diffuse calcified nodules involving the anterior and lateral airway walls, including the subglottic region. Histopathology demonstrated chronic inflammatory cell infiltration with squamous metaplasia. To explore the molecular basis of this condition, whole-genome sequencing (WGS) was performed using peripheral blood samples—the first such application in TO. WGS identified 766 germline mutations (including 27 high-impact variants) and 66 structural variations. Candidate genes were implicated in coagulation and inflammation (KNG1), arachidonic acid metabolism and extracellular matrix remodeling (PLA2G4D), ciliary dysfunction and mineralization (TMEM67), vascular calcification (CDKN2B-AS1), smooth muscle function (MYLK4), abnormal calcification (TRPV2, SPRY2, BAZ1B), fibrotic signaling (AHNAK2), and mucosal barrier integrity (MUC12/MUC19). Notably, despite systemic germline mutations, calcification was restricted to the airway. Conclusions: This case highlights that TO with vocal cord involvement can progress beyond a benign course to cause life-threatening airway obstruction. Integrating clinical, histological, and genomic findings, we propose a novel pathophysiological model in which systemic genetic susceptibility interacts with local immune cell infiltration and fibroblast-driven extracellular matrix remodeling, resulting in airway-restricted dystrophic calcification. This first genomic characterization of TO provides new insights into its pathogenesis and suggests that multi-omics approaches may enable future precision medicine strategies for this rare airway disease.