Intelligent quotient of late treated phenylketonuric patients: is brain damage still preventable?
DOI:
https://doi.org/10.54361/ljmr.v8i1.11Abstract
Over the past 30 years and since the first trial to treat phenylketonuria (PKU) by Horst Bickel and his coworkers, the dietary treatment of PKU has produced a generation of adult women with PKU who have minimal cognitive deficits and are now of child-bearing age. If PKU is detected early enough in infancy, mental retardation can be prevented by giving a diet containing a restricted amount of phenylalanine. The principle of therapy is that all newborn babies with phenylalanine concentration of 360 µmol or above are to be treated as early as possible to achieve a higher mental function in terms of intelligence quotient, blood phenylalanine levels should be maintained in the range of 120 - 360 µmol/l. Subnormal as well as high phenylalanine levels are to be avoided. In the last few years there are increasing published articles on late treated PKU patients. In these patients, the mean IQ was 57. For those treated after 2 months of age, recent studies have suggested that approx. 23% of those children have normal IQ. In our hospital most of our cases were late treated (15 patients out of 22), the age at which treatment was started ranges from 2 weeks to 9 years. It is noted that those patients who were diagnosed before 2 years of age (6 children) and were on strict phenylalanine low diet with a phenylalanine maintained less than 4mg/dl have a normal IQ (75 or above) (6 patients), one child has difficulty in speech, 2 children had border line IQ (above 70 and less than 75), two children had moderate learning difficulties (IQ above 35 and below 50), 4 children had severe learning difficulties (IQ above 20 and less than 35 of which two of them diagnosed before 2 years of age.
Downloads
References
Scriver Cr, Beaudet AL, Sly WS and Valle D. Metabolic and molecular basis of inherited disease. 1988, 7th Edition, McGraw-Hill Inc, USA.
Folling A. The discovery of phenylketonuria. Acta Pediatr. 1997, 407S, 4-10.
Bickel H. The first treatment of phenylketonuria. Eur J Pediatr. 1996, 1551: S2-3.
Przyrembel H. Recommendation for protein and amino acids intake in phenyketonuric patients. Eur J Pediatr. 55, 130S-133.
Smith I. Treatment of phenylalanine hydroxylase deficiency. Acta Pediatr. 1997, 407, 60-65.
Levy HL and Waisbern E. PKU in adolescents: rationale and neuropsychosocial factors in diet continuation. Acta Pediatr. 1994, 407: 92-97.
Smith, Beasly MG and Ades AE. Effects on intelligence of relaxing the low phenylalanine diet in phenylketonuria. Arch Dis Child. 1991, 66: 311-316.
Douglas M, et al. Early treated phenylketonuria adult neuropsychological outcome. J Pediatr. 1994, 124: 388-392.
Ceron, et al. Phenylketonuria: diet for life or not?. Acta Pediatr. 1991, 88: 664-666.
Brenton DP and Pietz J. Adult care in phenylketonuria and hyperphenylalaninemia: the relevance of neurological abnormalities. Eur J Pediatr. 2000, 159S; 2: 114-120.
Harper M and Reid AH. Use of restricted protein diet in the treatment of behavior disorder in a severely mentally retarded adult female phenylketonuric patient. J Ment Def Res. 1987, 31: 209-212.
Griffiths R. The abilities of young children by High WY Combe, UK, 1996.
Netley C, Hanley WB and Runder HL. Observation on intellectual functioning. Can Med Ass J. 1984, 131, 7: 751-755.
Poustie VJ and Rutherford P. Dietary intervention for phenylketonuria, Coherence Database Syst Rev. 2000, 92: CD001304.
Gassio R, Cam-Pistol J, et al. Do adult patients with phenylketonuria improve their quality of life after introduction/resumption of a phenylalanine restricted diet. Acta Pediatr. 2003, 92; 12: 146-148.
Leuzzi V, Trsimeni G, Gualdi GF, Antonozi I and Inherit J. Metab Dis. 1995, 8; 5: 624-634.
Koch R and Moseley K. Long term beneficial effects of the phenylalanine restricted diet in late diagnosed individuals with phenylketonuria. Mol Gent Metab. 1999, 67; 2: 148-155.
Downloads
Published
Issue
Section
License
Copyright (c) 2014 Kamila Elrfifi, Adel Zeglam, Mabrouka Zeletini, Fawzia Abourey, Souad Alhmidi (Author)

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Open Access Policy
Libyan journal of medical Research (LJMR).is an open journal, therefore there are no fees required for downloading any publication from the journal website by authors, readers, and institution.
The journal applies the license of CC BY (a Creative Commons Attribution 4.0 International license). This license allows authors to keep ownership f the copyright of their papers. But this license permits any user to download , print out, extract, reuse, archive, and distribute the article, so long as appropriate credit is given to the authors and the source of the work.
The license ensures that the article will be available as widely as possible and that the article can be included in any scientific archive.
Editorial Policy
The publication of an article in a peer reviewed journal is an essential model for Libyan journal of medical Research (LJMR). It is necessary to agree upon standards of expected ethical behavior for all parties involved in the act of publishing: the author, the journal editorial, the peer reviewer and the publisher.
Any manuscript or substantial parts of it, submitted to the journal must not be under consideration by any other journal. In general, the manuscript should not have already been published in any journal or other citable form, although it may have been deposited on a preprint server. Authors are required to ensure that no material submitted as part of a manuscript infringes existing copyrights, or the rights of a third party.
Authorship Policy
The manuscript authorship should be limited to those who have made a significant contribution and intellectual input to the research submitted to the journal, including design, performance, interpretation of the reported study, and writing the manuscript. All those who have made significant contributions should be listed as co-authors.
Others who have participated in certain substantive aspects of the manuscript but without intellectual input should only be recognized in the acknowledgements section of the manuscript. Also, one of the authors should be selected as the corresponding author to communicate with the journal and approve the final version of the manuscript for publication in the LJMR.
Peer-review Policy
- All the manuscripts submitted to LJMR will be subjected to the double-blinded peer-review process;
- The manuscript will be reviewed by two suitable experts in the respective subject area.
- Reports of all the reviewers will be considered while deciding on acceptance/revision or rejection of a manuscript.
- Editor-In-Chief will make the final decision, based on the reviewer’s comments.
- Editor-In-Chief can ask one or more advisory board members for their suggestions upon a manuscript, before making the final decision.
- Associate editor and review editors provide administrative support to maintain the integrity of the peer-review process.
- In case, authors challenge the editor’s negative decision with suitable arguments, the manuscript can be sent to one more reviewer and the final decision will be made based upon his recommendations.