What are the tests for prader-willi syndrome?

See below:: High resolution chromosomal analysis; fish (stands for fluorescence in situ hybridization, often done at the same time as a chromosome analysis); and new molecular tests: dna methylation test (confirms or rules out pws as a diagnosis, with over 99% accuracy);dna polymorphism studies (done to detect upd-uniparental disomy, requires blood samples from both parents and child for best accuracy).