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Impairment in tryptophan metabolism has been suggested to participate in the pathogenesis of ASD, however, further validation of its involvement is required. Additionally, its role in learning disabilities is still uninvestigated. Our objective was to evaluate some\u00a0aspects of tryptophan metabolism in ASD children (N\u2009=\u200945) compared to children with learning disabilities (N\u2009=\u200944) and healthy controls (N\u2009=\u200940) by measuring the expression levels of the <jats:italic>MAOA<\/jats:italic>, <jats:italic>HAAO<\/jats:italic> and <jats:italic>AADAT<\/jats:italic> genes using real-time RT-qPCR. We also aimed to correlate the expression patterns of these genes with parental ages at the time of childbirth, levels of serum iron, and vitamin D3 and zinc\/copper ratio, as possible risk factors for ASD. Results demonstrated a significant decrease in the expression of the selected genes within ASD children (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001) relative to children with learning disabilities and healthy controls, which significantly associated with the levels of our targeted risk factors (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.05) and negatively correlated to ASD scoring (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001). In conclusion, this study suggests that the expression of the <jats:italic>MAOA<\/jats:italic>, <jats:italic>HAAO<\/jats:italic> and <jats:italic>AADAT<\/jats:italic> genes may underpin the pathophysiology of ASD.<\/jats:p>","DOI":"10.1038\/s41598-021-86162-w","type":"journal-article","created":{"date-parts":[[2021,3,25]],"date-time":"2021-03-25T11:06:58Z","timestamp":1616670418000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Expression analysis of selected genes involved in tryptophan metabolic pathways in Egyptian children with Autism Spectrum Disorder and learning disabilities"],"prefix":"10.1038","volume":"11","author":[{"given":"Aliaa M.","family":"Higazi","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hanan M.","family":"Kamel","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emad A.","family":"Abdel-Naeem","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Noha M.","family":"Abdullah","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Doaa M.","family":"Mahrous","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ashraf M.","family":"Osman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2021,3,25]]},"reference":[{"key":"86162_CR1","unstructured":"Autism spectrum disorders. 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