Recent studies indicate that repetitive use is only weakly associated with the development of CTS. Rather, the cause of CTS is primarily genetic and also associated with certain medical conditions, such as diabetes, osteoarthritis, hypothyroidism, obesity, and rheumatoid arthritis. Traumatic injuries, such as wrist fractures, can also contribute to the development of CTS.

Web MD: Carpal Tunnel Syndrome and Overuse
National Institute of Health: Carpal Tunnel Syndrome
Wikipedia: Carpal Tunnel Syndrome