Cohort-level clinical trajectory and molecular landscape of idiopathic subglottic stenosis for precision laryngology-a study of the Canadian airways research (CARE) group.

Background: First described in 1972, idiopathic subglottic stenosis (iSGS) is a serious chronic orphan disease characterised by recurrent scarring of the subglottis. Although the cause is unknown, iSGS is almost exclusively restricted to Caucasian females typically in their fourth to sixth decade. However, given its rare incidence (1:400,000), understanding the clinical trajectory and molecular factors associated with iSGS disease development and prognosis has been difficult. In the current study we sought to unravel the pathogenesis of iSGS at the clinical, transcriptional, and genetic level in a prospective cohort.

Methods: We prospectively enrolled 126 patients with iSGS, 104 controls, and 13 patients with traumatic SGS. Within this cohort, we profiled 114 human epiglottis and 121 human subglottis biopsies across three different conditions: control, iSGS, and intubation-related traumatic stenosis using bulk and single nucleus RNA-sequencing. Whole exome sequencing for germline variants was performed for 70 controls and 75 patients with iSGS.

Findings: Patients with iSGS received a median number of five (range 0-18) surgical dilations at a rate of 1.031 dilations (range: 0.12-6.2) per year. Older age at diagnosis and higher Cotton-Myers grade were associated with increased number of surgical dilations over time. Cohort-level bulk transcriptomics found that iSGS pathology was restricted within the subglottis and did not affect anatomically adjacent epiglottis, opposite to previous hypotheses. We further identified cellular subsets associated with iSGS prognosis and severity. Finally, patients with iSGS exhibit lower testosterone predicted using a polygenic score.

Interpretation: Together, our data refines our understanding of laryngeal biology and provides insights into the clinical trajectory of subglottic stenoses. Future research should explore the role of testosterone in the development of iSGS.

Funding: This study was funded by a grant from the American Laryngology Association (#1082), an Academic Medical Organization of Southwestern Ontario innovation fund grant (INN21-016), grant support from the Departments of Otolaryngology-Head and Neck Surgery at University of Toronto and Western University. ACN was supported by the Wolfe Surgical Research Professorship in the Biology of Head and Neck Cancers Fund. PYFZ was supported by a Vanier Canada Graduate Scholarship and PSI foundation fellowship.