Since the aim of our study was to find a potential marker able to distinguish idiopathic CTS from TTR-related CTS, we focused on pre-symptomatic carriers with only CTS (still not with polyneuropathy), therefore 21 hands (11 right, 10 left) from 16 patients (10 women, 6 men; 5 patients had bilateral CTS; mean age 53.9 ± 12.2, mean BMI 24.4 ± 4) were considered in this sub-analysis. This evidence concerns the gene TTR and carpal tunnel syndrome.