Background: The Prader-Willi syndrome (PWS) is a disease of genetic origin. It is characterized by neonatal hypotonia, hypogonadism, hiperfagia leading to obesity, low stature, developmental delay, moderate mental retardation, abnormal behavior and characteristic facial appearance. It is caused by the loss or the inactivation of paternal genes of the imprinted region 15q11-13. There are different genetic causes: paternal 15q11-q13 deletion in 70% of patients, maternal uniparental disomy in the 20-25% and less than 5% have an imprinting defect. We present the results obtained in the transverse clinical - genetic study of 77 PWS patients.
Patients and methods: There has been realized the study of 374 suspected PWS patients. Cytogenetics studies of bands G and hybridization in situ fluorescent (FISH) and molecular genetics analysis of microsatellites, Southern blot, MS-PCR and sequenciation were carried out. Holm's criteria use for the correlation phenotype - genotype in 48 patients.
Results: PWS was confirmed in 77 patients, 46 deletion, 16 uniparental disomy, two imprinting defect and 13 only PWS methylation pattern. Significant differences do not observe in the correlation phenotype - genotype.
Conclusions: The frequencies of the molecular alterations, 71.87 % deletion, 25 % UPD and 3.12 % DI, they are similar to described in the literature. It presents the algorithm of diagnosis used with the MS-PCR as rapid technology to confirm PWS.