is reported to be 3–14%
in various areas in Asia, including 4.6% in Northern Thailand, 4.1% in Hong Kong, and 4.1% in
Guangdong Province in China[1,2]. The frequency of the nondeletional gene mutation, Constant Spring,
was found to be between 1 and 6% in various areas of Southeast Asia, with the highest rate in
Northeastern Thailand and Laos[3]. In North America and Europe