Li Chi-keng has the relatively less severe "Becker" type. The disease develops relatively late. anytime between the ages of five and 25. Because it does not affect the heart muscles, there are cases of people living into their sixties.
李繼庚則是屬於症狀略輕微的「貝克型」（Becker），這種型發病較慢，從五歲起到二十五歲都有可能，由於不會發生心肌障礙，有活到六十多歲的例子。