[Diagnosis of Prader-Willi syndrome. Considerations on a case of erroneous diagnosis].

Prader-Willi syndrome is a genetic disease, which is clinically characterized by neonatal hypotonia, feeding problems in the first year of life, excessive eating with severe obesity from the second year of life, developmental delay, hypogonadism, typical facial features, short stature, behaviour problems, mental retardation. It is caused by a genomic imprinting disorder, i.e., lacking expression of paternally derived genes located on the long arm of chromosome 15. We present a case of a child with a neonatal diagnosis of Prader-Willi syndrome, founded on some facial dysmorphic features and a partial deletion of 15q, which we belied thanks to an anamnestic and clinical revaluation, and a metilation test. We also present main topics about Prader-Willi syndrome diagnosis, including clinical and endocrinological features, scoring system, and genetics.