OBJECTIVE: To evaluate the conventional cytogenetic methods in genetic diagnosis 
and prenatal diagnosis in the family with a proband of Angelman syndrome (AS).
METHODS: High-resolution G-banding karyotyping and fluorescence in situ 
hybridization (FISH) on metaphase chromosomes were performed.
RESULTS: Two AS patients and 1 normal fetus in the family were successfully 
detected by FISH.
CONCLUSION: Our result demonstrated that patient with type I AS could be 
detected by combining the techniques of high-resolution G-banding and FISH with 
clinical observation, which would offer accurate genetic counseling information 
to the geneticists and provide the prenatal diagnosis for the AS family.