<prompt> Which of the following feature is not seen in Prader Willi syndrome?ObesityMental retardationAtaxiaHypotonia  <response>: Ans. is c i.e., Ataxia Prader willi syndrome It is due to paternal genomic imprinting in which there is deletion on paternal chromosome 15. They are characterized by hypotonia, obesity, short stature, mental retardation, hypogonadism, hyperphagia, and short hand and feet. There is decrease in GnRH, LH, FSH and GH. Ghrelin levels are raised. 