[Detection of the mutant phenylalanine hydroxylase gene by dideoxy fingerprinting].

OBJECTIVE: To establish a method with high efficiency in detecting phenylalanine hydroxylase (PHA) gene mutations and hence to rapidly diagnose prenatal fetals with phenylketonuria. METHODS: Dideoxy fingerprinting (ddF) was used. It is a hybrid method of dideoxy sequencing and single strand conformation polymorphism (SSCP); it can effectively detect the presence of mutant genes and would not be limited by the length of the amplified products, by ddF, the mutant genes Y165X, Y204C and Q355H of PAH genes were detected. RESULTS: Many bands showed altered migration, compared with the controls. Abnormal band migration in Y165X and Q355H was also detected by SSCP, but it was not detected in Y204C which had large amplified products. CONCLUSION: Compared with SSCP, ddF is a more sensitive method detecting gene mutations in large fragments, ddF is a practicable method for detecting gene mutations.