RESUMO
PURPOSE: To detect microdeletion of 15q11-13 region, high resolution cytogenetic analysis or FISH with probe at Prader-Willi syndrome region can be used. We tried to evaluate whether FISH with SNRPN is a more effective method than G-banding microscope in the diagnosis of Prader-Willi syndrome. MEHTODS: Peripheral blood sampling was done on five patients who we suspected of Prader-Willi syndrome clinically and lymphocytes from peripheral blood sampling were cultured. G-banding microscope was used to detect the microdeletion in chromosome 15 and FISH with SNRPN probe was used to detect signal defect in band q11-q13 in chromosome 15. RESULTS: There was a fluorescent signal defect in band 15 q11-q13 in one of chromosome 15 in 4 children with FISH method and only one patient was diagnosed with Prader-Willi syndrome with G-banding microscope. CONCLUSION: FISH analysis is more accurate, objective, and time saving than G-banding microscope, therefore it can be considered as a more adequate screening test for the diagnosis of Prader-Willi syndrome.