DIRC3-IGFBP5 is a shared genetic risk locus and therapeutic target for carpal tunnel syndrome and trigger finger

Trigger finger (TF) and carpal tunnel syndrome (CTS) are two common non-traumatic hand disorders that frequently co-occur. By identifying TF and CTS cases in UK Biobank (UKB), we confirmed a highly significant phenotypic association between the diseases. To investigate the genetic basis for this association we performed a genome-wide association study (GWAS) including 2,908 TF cases and 436,579 European controls in UKB, identifying five independent loci. Colocalization with CTS summary statistics identified a co-localized locus at DIRC3 (lncRNA), which was replicated in FinnGen and fine-mapped to rs62175241. Single-cell and bulk eQTL analysis in fibroblasts from healthy donors (n=79) and tenosynovium samples from CTS patients (n=77) showed that the disease-protective rs62175241 allele was associated with increased DIRC3 and IGFBP5 expression. IGFBP5 is a secreted antagonist of IGF-1 signaling, and elevated IGF-1 levels were associated with CTS and TF in UKB, thereby implicating IGF-1 as a driver of both diseases.