This project aims to develop the use of hormones as biomarkers in the screening and diagnosis of Angelman Syndrome (AS) (prevalence 1/15000). There is an unequivocal need for an affordable, noninvasive and reliable biomarker that can predict the onset of or diagnose AS. Our novel basic science research work suggests that certain hormone levels are rendered abnormal in the pathobiological course of this disease, thus rendering these hormones as testable screening biomarkers for AS. Thus, quantitation of hormone levels, via High Performance Liquid Chromatography (HPLC) or any other validated method, in human blood samples could be used as a screening, as well as a diagnostic tool for AS, and maybe other neurological disorder. To our knowledge, the “Use of hormones as a biomarkers for screening and diagnosis of AS” is a highly innovative idea with an exciting potential. To accomplish this objective, we have set the following specific aims: 1- To establish, in house, quantification of hormone levels in blood samples of normal humans via HPLC based on an already published method in the literature. 2- To compare hormone levels in AS patients versus their normal siblings. The timeline of this project is summarized as follows: Aim 1 is predicted to be completed the first 3 months of year 1. Aim 2 is predicted to be started on the second month of year 1 and completed by end of year 1. As for the therapeutic significance, the need for a non-invasive routine AS screening test during the first months of infancy and at later age, and the need for an affordable molecularly defined diagnostic test are highly warranted for AS. As for the group of patients that has been identified with AS on clinical basis only, this kind of molecular test is highly necessary. Thus, hormone markers could be instrumental in: 1- Affordably screening and predicting incidence of AS in infants starting day one after birth, and possibly even before birth. 2- Allowing possible prophylactic and protective clinical measures to be taken before onset of disease in cases where test is positive in infants. 3- Opening the door to research related to prophylactic measures that can be taken to prevent or to alleviate onset of symptoms seen in AS. 4- Possibly providing molecular basis for AS cases that are solely diagnosed on a clinical basis. 5- Possibly presenting a new reliable diagnosis tool for AS.