The chemical mismatch cleavage (CMC) analysis was first described by Cotton et al. (1 ) and has successfully been used for detection and identification of mutations in several genes implicated in causing human genetic disorders (2 -7 ). Compared with some current methods, such as denaturing gradient gel electrophoresis (8 ) and singlestranded conformation polymorphism (SSCP) which detects polymorphism in short DNA fragments, CMC has a higher diagnostic sensitivity and can analyze larger DNA fragment lengths (9 ).