Carpal tunnel syndrome (CTS) and trigger finger (TF) are the two most common diseases of the hand, accounting for over 60,000 operations per year in the UK alone, and large economic cost worldwide.
It is well known among hand surgeons that these two conditions often occur together, but the reason for this is unknown.
Dr Akira Wiberg, NIHR Clinical Lecturer in Plastic Surgery and co-senior author of the study said: “We’ve known for a long time that trigger finger and carpal tunnel syndrome – two of the commonest hand diseases worldwide – frequently co-exist in patients, but the reason for this has remained unclear. We’ve shown for the first time that this co-occurrence can partly be explained by genetics.”
The Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences (NDORMS) researchers hypothesised that the co-occurrence of carpal tunnel syndrome and trigger finger may in part be explained by a shared genetic predisposition. To test the theory, they performed a genome-wide association study (GWAS) of trigger finger in the UK Biobank, a population-based cohort of approx. half a million participants from the UK, and discovered five regions in the genome where sufferers of trigger finger carry, on average, different genetic variants from people who don’t have trigger finger.
One of those genetic variants is the same variant that increases the risk of carpal tunnel syndrome, which the team previously discovered in their 2019 GWAS of carpal tunnel syndrome. The genetic variant allows for increased signalling through a growth hormone known as “Insulin-like Growth Factor 1”, or IGF-1 pathway.