{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T11:47:20Z","timestamp":1791892040769,"version":"4.3.4"},"reference-count":18,"publisher":"Wiley","issue":"S3","license":[{"start":{"date-parts":[[2010,9,30]],"date-time":"2010-09-30T00:00:00Z","timestamp":1285804800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J of Inher Metab Disea"],"published-print":{"date-parts":[[2010,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Investigations into the biochemical markers associated with executive function (EF) impairment in children with early and continuously treated phenylketonuria (ECT\u2010PKU) remain largely phenylalanine\u2010only focused, despite experimental data showing that a high phenylalanine:tyrosine (phe:tyr) ratio is more strongly associated with EF deficit than phe alone. A high phe:tyr ratio is hypothesized to lead to a reduction in dopamine synthesis within the brain, which in turn results in the development of EF impairment. This paper provides a snapshot of current practice in the monitoring and\/or treatment of tyrosine levels in children with PKU, across 12 countries from Australasia, North America and Europe. Tyrosine monitoring in this population has increased over the last 5 years, with over 80% of clinics surveyed reporting routine monitoring of tyrosine levels in infancy alongside phe levels. Twenty\u2010five percent of clinics surveyed reported actively treating\/managing tyrosine levels (with supplemental tyrosine above that contained in PKU formulas) to ensure tyrosine levels remain within normal ranges. Anecdotally, supplemental tyrosine has been reported to ameliorate symptoms of both attention deficit hyperactivity disorder and depression in this population. EF assessment of children with ECT\u2010PKU was likewise highly variable, with 50% of clinics surveyed reporting routine assessments of intellectual function. However when function was assessed, test instruments chosen tended towards global measures of IQ prior to school entry, rather than specific assessment of EF development. Further investigation of the role of tyrosine and its relationship with phe and EF development is needed to establish whether routine tyrosine monitoring and increased supplementation is recommended.<\/jats:p>","DOI":"10.1007\/s10545-010-9211-6","type":"journal-article","created":{"date-parts":[[2010,9,29]],"date-time":"2010-09-29T08:57:33Z","timestamp":1285750653000},"page":"417-420","source":"Crossref","is-referenced-by-count":14,"title":["Tyrosine monitoring in children with early and continuously treated phenylketonuria: results of an international practice survey"],"prefix":"10.1002","volume":"33","author":[{"given":"Rachael","family":"Sharman","sequence":"first","affiliation":[{"name":"School of Psychology and Counselling Queensland University of Technology PO Box 2434 Queensland QLD 4001 Australia"},{"name":"Institute of Health and Biomedical Innovation Queensland University of Technology Queensland 4059 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karen A.","family":"Sullivan","sequence":"additional","affiliation":[{"name":"School of Psychology and Counselling Queensland University of Technology PO Box 2434 Queensland QLD 4001 Australia"},{"name":"Institute of Health and Biomedical Innovation Queensland University of Technology Queensland 4059 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ross McD.","family":"Young","sequence":"additional","affiliation":[{"name":"Institute of Health and Biomedical Innovation Queensland University of Technology Queensland 4059 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James J.","family":"McGill","sequence":"additional","affiliation":[{"name":"Department of Metabolic Medicine Royal Children's Hospital, Herston Queensland 4029 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2010,9,30]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1037\/0894-4105.17.3.458"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1023\/B:BOLI.0000028725.37345.62"},{"key":"e_1_2_6_4_1","volume-title":"The PKU handbook","year":"2005"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/PL00014388"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1093\/clinchem\/44.12.2405"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.2307\/1166208"},{"key":"e_1_2_6_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-3476(86)80220-7"},{"key":"e_1_2_6_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0149-7634(02)00040-4"},{"key":"e_1_2_6_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0028-3932(01)00078-1"},{"key":"e_1_2_6_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/1467-8624.00370"},{"key":"e_1_2_6_12_1","unstructured":"National Institutes of Health(2000)NIH consensus panel recommends comprehensive approach to life long care for PKU.http:\/\/www.nichd.nih.gov\/news\/releases\/pku.cfm. 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