Introduction Prader-Willi syndrome (PWS) is a condition triggered by a deletion or disturbance of genes in the proximal arm of chromosome 15 or by maternal disomy in the proximal arm of chromosome 15. Generally related charactnnneristics of this syndrome include weakened fetal activity, obesity, hypotonia, mental obstruction, short build, hypogonadotropicl hypogonadism, strabismus, and slight hands and feet. In 1887, Langdon Down defined the first patient with Prader-Willi syndrome as a teenage girl