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Wappner R, Cho S, Kronmal RA, Schuett V, Seashore MR. Management of phenylketonuria for optimal outcome: a review of guidelines for phenylketonuria management and a report of surveys of parents, patients, and clinic directors. Pediatrics 1999; 104:e68. [PMID: 10586002 DOI: 10.1542/peds.104.6.e68] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The development of guidelines for phenylketonuria (PKU) management in the United Kingdom has resulted in much discussion in the community of parents and PKU clinics and parents have asked why the United States does not have such guidelines. The objective of this report is to discuss PKU management in the United States, the British guidelines on PKU management, and the feasibility, suitability, and mechanism of developing PKU management guidelines in the United States. METHODS Members of the American Academy of Pediatrics (AAP) Committee on Genetics (COG) reviewed the literature and conducted surveys of parents of children with PKU, young adults with PKU, and directors of PKU clinics in the United States. A meeting was held at the National Institute of Child Health and Human Development to review the AAP/COG efforts at reviewing the status of PKU management and guideline development in the United States. RESULTS The British guidelines are more stringent than the PKU management practices in many parts of the United States. Evidence exists that stricter management improves developmental outcome. The parents who responded to the surveys indicated willingness to comply with more stringent dietary management if that would improve outcome. They also identified problems that make such management difficult. The clinic directors supported the timeliness of the review. Some had begun a trend toward more stringent control of blood phenylalanine concentrations, at least in the first 4 years of life. CONCLUSION The AAP Committee on Genetics will complete its subject review of the management of PKU. Guidelines for care of PKU in the United States probably would look quite similar to the existing guidelines in other countries. The parents surveyed supported more stringent PKU management, but information from a broader distribution of parents would provide a more representative view. The status of the US health care system creates problems for improved PKU management in the United States that do not exist in the countries already following stricter guidelines.
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Affiliation(s)
- R Wappner
- Riley Hospital for Children, Section of Pediatric Metabolism/Genetics, Indianapolis, Indiana, USA
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52
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Seashore MR, Wappner R, Cho S, de La Cruz F. Development of guidelines for treatment of children with phenylketonuria: report of a meeting at the National Institute of Child Health and Human Development held August 15, 1995, National Institutes of Health, Bethesda, Maryland. Pediatrics 1999; 104:e67. [PMID: 10586001 DOI: 10.1542/peds.104.6.e67] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To convene a small group of experts in diagnosis and management of PKU to discuss the following issues: the Subject Review of PKU management being performed by the American Academy of Pediatrics (AAP) Committee on Genetics (COG), the published British guidelines on PKU management, and the feasibility, suitability, and mechanism of developing PKU management guidelines for the United States. METHODS A 1-day meeting was held at the National Institutes of Health under the auspices of National Institute of Child Health and Human Development, convening experts in PKU diagnosis and management and members of the AAP/COG. RESULTS The group reviewed the published reports of outcomes of treatment of PKU and the British guidelines that were developed based on those data. It also reviewed the results of surveys of directors of clinics that manage PKU, parents of children with PKU, and young adults with PKU. CONCLUSION The group supported the efforts of the AAP/COG to perform this review of PKU management. The group concluded that significant issues need to be resolved to provide sufficient information to establish US guidelines for PKU management. The establishment of such guidelines is an important next step in PKU management in the United States.
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Affiliation(s)
- M R Seashore
- Departments of Genetics and Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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53
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Affiliation(s)
- C R Scriver
- McGill University Health Centre, McGill University-Montreal Children's Hospital Research Institute, Montreal, Canada
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54
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Stemerdink NBA, van der Molen MW, Kalverboer AF, van der Meere JJ, Huisman J, de Jong LW, Slijper FME, Verkerk PH, van Spronsen FJ. Prefrontal Dysfunction in Early and Continuously Treated Phenylketonuria. Dev Neuropsychol 1999. [DOI: 10.1207/s15326942dn160103] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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55
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Ferguson C, Morris AM. Changes in serum phenylalanine after overnight fasts in youngsters with phenylketonuria. J Hum Nutr Diet 1999. [DOI: 10.1046/j.1365-277x.1999.00158.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- C. Ferguson
- *Newcastle Nutrition, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne, UK
| | - A. M. Morris
- †Department of Child Health, Royal Victoria Infirmary, Newcastle upon Tyne, UK
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56
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Abstract
The start of newborn screening for phenylketonuria (PKU) during the early 1970s has given rise to an increasing number of women who have been identified and successfully treated for the disease in childhood and are now preparing to have children of their own. Early detection and initiation of nutritional therapy before conception is key to a successful pregnancy outcome. Nurses who understand the pathophysiology, dietary limitations, and management of PKU in pregnancy can provide the care necessary for optimal maternal and neonatal health.
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Affiliation(s)
- R B Kirby
- St. Peter's University Hospital, Department of Education and Development, New Brunswick, NJ 08903-0591, USA
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57
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Sarkissian CN, Shao Z, Blain F, Peevers R, Su H, Heft R, Chang TM, Scriver CR. A different approach to treatment of phenylketonuria: phenylalanine degradation with recombinant phenylalanine ammonia lyase. Proc Natl Acad Sci U S A 1999; 96:2339-44. [PMID: 10051643 PMCID: PMC26785 DOI: 10.1073/pnas.96.5.2339] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/1998] [Accepted: 12/07/1998] [Indexed: 11/18/2022] Open
Abstract
Phenylketonuria (PKU), with its associated hyperphenylalaninemia (HPA) and mental retardation, is a classic genetic disease and the first to have an identified chemical cause of impaired cognitive development. Treatment from birth with a low phenylalanine diet largely prevents the deviant cognitive phenotype by ameliorating HPA and is recognized as one of the first effective treatments of a genetic disease. However, compliance with dietary treatment is difficult and when it is for life, as now recommended by an internationally used set of guidelines, is probably unrealistic. Herein we describe experiments on a mouse model using another modality for treatment of PKU compatible with better compliance using ancillary phenylalanine ammonia lyase (PAL, EC 4.3.1.5) to degrade phenylalanine, the harmful nutrient in PKU; in this treatment, PAL acts as a substitute for the enzyme phenylalanine monooxygenase (EC 1.14.16.1), which is deficient in PKU. PAL, a robust enzyme without need for a cofactor, converts phenylalanine to trans-cinnamic acid, a harmless metabolite. We describe (i) an efficient recombinant approach to produce PAL enzyme, (ii) testing of PAL in orthologous N-ethyl-N'-nitrosourea (ENU) mutant mouse strains with HPA, and (iii) proofs of principle (PAL reduces HPA)-both pharmacologic (with a clear dose-response effect vs. HPA after PAL injection) and physiologic (protected enteral PAL is significantly effective vs. HPA). These findings open another way to facilitate treatment of this classic genetic disease.
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Affiliation(s)
- C N Sarkissian
- Departments of Biology, Human Genetics, and Pediatrics, McGill University, and Debelle Laboratory, McGill University-Montreal Children's Hospital Research Institute, Montreal, QC, H3H 1P3, Canada
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58
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Lord J, Thomason MJ, Littlejohns P, Chalmers RA, Bain MD, Addison GM, Wilcox AH, Seymour CA. Secondary analysis of economic data: a review of cost-benefit studies of neonatal screening for phenylketonuria. J Epidemiol Community Health 1999; 53:179-86. [PMID: 10396496 PMCID: PMC1756840 DOI: 10.1136/jech.53.3.179] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
STUDY OBJECTIVE To estimate the net financial benefit of neonatal screening for phenylketonuria (PKU): by a simple pooling of cost data from the literature; and by a more complex modelling approach. DESIGN A systematic literature review was conducted to identify papers containing data on the monetary costs and benefits of neonatal screening for PKU. The methodological quality of the studies was appraised, and data were extracted on resource use and expenditure. Monetary data were converted to common currency units, and standardised to UK incidence rates. Net benefits were calculated for median, best case and worst case scenarios, and the effect of excluding poor quality studies and data was tested. The net benefit was also estimated from a model based on data from the literature and assumptions appropriate for the current UK situation. Extensive sensitivity analysis was conducted. MAIN RESULTS The direct net benefit of screening based on the median costs and benefits from the 13 studies identified was 143,400 Pounds per case detected and treated (39,000 Pounds and 241,800 Pounds for worst case and best case scenarios respectively). The direct net benefit obtained by the modelling approach was lower at 93,400 Pounds per case detected and treated. Screening remained cost saving under sensitivity analysis, except with low residential care costs (less than 12,300 Pounds per annum), or very low incidence rates (less than 1 in 27,000). CONCLUSIONS The economic literature on PKU screening is of variable quality. The two methods of secondary analysis lead to the same conclusion: that neonatal PKU screening is worthwhile in financial terms alone in the UK, and that it justifies the infrastructure for collecting and testing neonatal blood samples. This result cannot necessarily be extrapolated to other countries.
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Affiliation(s)
- J Lord
- St George's Hospital Medical School, London
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59
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Affiliation(s)
- H Wilkinson
- Department of Chemical Pathology, York District Hospital, UK
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60
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Griffiths P, Campbell R, Robinson P. Executive function in treated phenylketonuria as measured by the one-back and two-back versions of the continuous performance test. J Inherit Metab Dis 1998; 21:125-35. [PMID: 9584263 DOI: 10.1023/a:1005339524847] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The executive dysfunction hypothesis in treated phenylketonuria was investigated by means of the one-back and two-back versions of the continuous performance test. Eleven non-retarded, primary school-age children with classical phenylketonuria who had been treated early and continuously were indistinguishable from healthy, matched controls on the measures and test performance was not predicted by historical or concurrent plasma phenylalanine concentrations. Mean lifetime phenylalanine concentrations for the phenylketonuric subjects were within ranges currently recommended as dietary optima in the United Kingdom. The negative neuropsychological test findings add weight to the rationale for this policy.
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Affiliation(s)
- P Griffiths
- Department of Psychology, University of Stirling, UK
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61
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62
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Griffiths P, Ward N, Harvie A, Cockburn F. Neuropsychological outcome of experimental manipulation of phenylalanine intake in treated phenylketonuria. J Inherit Metab Dis 1998; 21:29-38. [PMID: 9501267 DOI: 10.1023/a:1005307229813] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Blood phenylalanine concentrations were experimentally increased for 3 months by means of a phenylalanine-complemented amino acid supplement in a group of 16 children aged 10-16 years with classical phenylketonuria who had been treated early and who had remained on the restricted diet. Average concentrations achieved during challenge were between 1000 and 1300 mumol/L. Psychological outcome was measured by a neuropsychological battery consisting of tests of verbal and spatial memory, attention and fine motor coordination. A triple-blind, repeated measures, randomized, crossover design was adopted to control for practice and expectancy effects. Subjects were assessed at baseline and at the end of the first and second phenylalanine manipulation periods. Significant interactions (ANOVA) emerged as predicted for phenylalanine concentrations, but similar crossover effects were not found for any of the neuropsychological tests. The results suggested that medium-term hyperphenylalaninaemia in treated PKU is not harmful to psychological functioning in older children and adolescents who have been continuously treated up to and beyond age 10 years, though the susceptibility of executive functions needs to be further researched. The findings add some weight to the idea that by late childhood the vulnerability of the nervous system to the neurotoxic influence of phenylalanine may be much reduced.
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Affiliation(s)
- P Griffiths
- Department of Psychology, University of Stirling, UK
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63
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Whitehead H, Holmes J, Roberts R, al-Mandhari NA, Greer A, Thom R, Donnelly P, Carson D, Traub AI, Hadden D. Maternal phenylketonuria 1987 to 1993, pregnancy outcome and early infant development: the Northern Ireland experience. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1996; 103:1041-4. [PMID: 8863706 DOI: 10.1111/j.1471-0528.1996.tb09558.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- H Whitehead
- Sir George E. Clark Metabolic Unit, Royal Victoria Hospital, Belfast, UK
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64
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Burgard P, Schmidt E, Rupp A, Schneider W, Bremer HJ. Intellectual development of the patients of the German Collaborative Study of children treated for phenylketonuria. Eur J Pediatr 1996; 155 Suppl 1:S33-8. [PMID: 8828606 DOI: 10.1007/pl00014245] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In a multicentric and interdisciplinary approach the German Collaborative Study of Children Treated for Phenylketonuria (PKU) investigates prospectively the effects of early started strict dietary treatment on the growth and development of 140 patients. The present paper focuses on longitudinal intelligence data from 4, 5 and 9 years of age of 89 patients in relation to the quality of dietary control in comparison to 200 healthy children tested by the same protocol. Cluster analysis of phenylalanine (Phe) levels distinguished a cluster of good dietary control with Phe levels according to the recommendation of maintaining Phe levels below 360 mumol/l, a cluster of poor dietary control with Phe levels greater than 600 mumol/l after the age of 3 years, and a cluster of intermediate control. Intelligence quotients (IQ) and Phe clusters were inversely related with non-significant differences between the clusters good and intermediate. On average, all three clusters scored significantly lower than healthy age peers. Mean IQ scores decreased for patients as well as for healthy children due to different tests used at different measurement occasions. Patients with poor dietary control showed a steeper decrease between 4 and 5 years than patients with better dietary control. Between 5 and 9 years IQ differences between patients and healthy children remained stable. Verbal IQs were higher than performance IQs for patients as well as for healthy children. It is concluded that after early and strict treatment during the pre-school years Phe levels, in the range observed, do not influence IQ development until the age of 9 years. IQ subscale pattern indicate that PKU results in a generalized reduction of IQ instead of disturbing specific abilities. It remains to be investigated whether higher Phe levels are also innocuous and/or may result in late effects.
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Affiliation(s)
- P Burgard
- Department of General Pediatrics, University of Heidelberg, Germany
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65
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Cockburn F, Clark BJ. Recommendations for protein and amino acid intake in phenylketonuric patients. Eur J Pediatr 1996; 155 Suppl 1:S125-9. [PMID: 8828627 DOI: 10.1007/pl00014228] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The methods for the determination of protein requirements are reviewed and the difficulties in achieving the recommendations of the dietary management of phenylketonuria proposed by a Medical Research Council Working Party on Phenylketonuria using currently available low phenylalanine (Phe) protein substitutes and low protein foods are examined. These recommendations are that all infants whose blood Phe concentrations exceed 600 mumol/l in the presence of a normal or low plasma tyrosine and an otherwise normal plasma amino acid profile while receiving a normal protein intake (2-3 g/kg/day), should start a low Phe diet immediately. Infants whose blood Phe concentrations remain persistently between 400 and 600 mumol/l for more than a few days should also start treatment. The diet should contain a protein substitute which is Phe free (or at least very low in Phe) and otherwise nutritionally complete with a composition sufficient to provide 100-120 mg/kg per day of tyrosine and a total amino acid intake of at least 3 g/kg per day in children under 2 years of age. In children over 2 years the intake of amino acids should be maintained at a level of 2 g/kg per day. The protein substitute should be spread as evenly as possible through the 24 h. Blood Phe concentrations should be maintained between 120 and 360 mumol/l. In children aged over 10 years it is suggested that the protein substitute should supply the protein reference nutrient intake + 50%. An upper blood Phe limit of 480 mumol/l rather than 360 mumol/l may be acceptable in school age children. Adults and adolescents should continue treatment with the aim to maintain blood Phe concentrations no higher than 700 mumol/l. During the period before conception and during pregnancy women should aim to have plasma Phe concentrations between 60-250 mumol/l.
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Affiliation(s)
- F Cockburn
- Department of Child Health, Royal Hospital for Sick Children, Yorkhill, Glasgow, UK
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66
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Hanley WB, Koch R, Levy HL, Matalon R, Rouse B, Azen C, de la Cruz F. The North American Maternal Phenylketonuria Collaborative Study, developmental assessment of the offspring: preliminary report. Eur J Pediatr 1996; 155 Suppl 1:S169-72. [PMID: 8828638 DOI: 10.1007/pl00014240] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Preliminary results of 2-year Bayley and 4-year McCarthy test scores are presented. To date numbers are too small to statistically correlate:- offspring from pregnancies in which diet was started prior to conception, offspring from pregnancies with phenylalanine (Phe) levels of 120-360 mumol/l versus 360-600 mumol/l, influence of home environment, influence of maternal nutrition, language development, behaviour/hyperactivity, Revised Wechsler Intelligence Score, school performance and learning disabilities. Two-year Bayley scores (mental and motor) revealed a median developmental quotient of 113 in 58 offspring from control pregnancies, 104 in 19 offspring from untreated "non-phenylketonuria (PKU) mild hyperphenylalaninaemia" (natural Phe levels < 600 mumol/l) pregnancies, 104 in 32 offspring from pregnancies whose Phe levels decreased on treatment to < 600 mumol/l by 10 weeks gestation and remained in that range for the remainder of the pregnancy, 98 in offspring from 32 pregnancies where permanent control was not achieved until 10-20 weeks and 72 in offspring from 51 pregnancies where control was not attained until after 20 weeks gestation. IQ scores determined by the McCarthy test at age 4-5 years revealed a mean of 112 in 43 offspring of control mothers, 99 in 12 offspring of "non PKU mild hyperphenylalaninaemia" women, 93 in 14 offspring whose mother's Phe levels were continuously under 600 mumol/l by 10 weeks gestation, 88 in 24 offspring from pregnancies in metabolic control by 10-20 weeks and 73 in 28 offspring of pregnancies not in metabolic control until after 20 weeks gestation. These preliminary results suggest that early and adequate dietary treatment during pregnancy in maternal PKU may provide some protection to the fetus for later intellectual development but much more data is required before definitive statements about cognition can be made.
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Affiliation(s)
- W B Hanley
- Division of Clinical Genetics, Hospital for Sick Children, Toronto, Ontario, Canada
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67
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MacDonald A, Rylance G, Hall SK, Asplin D, Booth IW. Factors affecting the variation in plasma phenylalanine in patients with phenylketonuria on diet. Arch Dis Child 1996; 74:412-7. [PMID: 8669956 PMCID: PMC1511531 DOI: 10.1136/adc.74.5.412] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The optimal dietary management of children with phenylketonuria (PKU) has rarely been rigorously explored. The aim of this study was to assess longitudinally the effects of three factors thought to influence plasma phenylalanine concentrations in PKU: total energy intake; protein intake from natural foods allowed freely in addition to allocated phenylalanine exchanges; and the distribution of protein substitute throughout the day. Nineteen subjects, 15 girls and four boys aged 1-16 years, were enrolled. Food intake was weighed, and twice daily plasma phenylalanine concentrations measured during either 3-day or 4-day periods, for a total of 21 days throughout six months. There was a negative correlation between the percentage of protein substitute eaten by the time of the evening meal and the fall in plasma phenylalanine concentration during the day (r = -0.941; p < 0.0001). On average, 49% of pre-evening meal plasma phenylalanine concentrations were less than 100 mumol/l in children who had taken at least 65% of their protein substitute by the time of their evening meal. There was no correlation between excess natural protein intake from freely allowed foods and (a) pre-breakfast or pre-evening meal plasma phenylalanine concentrations or (b) the daily change between pre-breakfast and pre-evening meal concentrations. Nor was there any correlation between excess natural protein intake on the previous day and plasma phenylalanine concentration on the following morning. Energy intake was not correlated with plasma phenylalanine concentrations. It is therefore preferable to distribute the protein substitute evenly through the day in order to achieve stable phenylalanine concentrations, rather than to carry out further fine manipulation of the phenylalanine intake, which would make management of the diet even more difficult.
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Affiliation(s)
- A MacDonald
- Children's Hospital, Ladywood Middleway, Birmingham
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68
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Riva E, Agostoni C, Biasucci G, Trojan S, Luotti D, Fiori L, Giovannini M. Early breastfeeding is linked to higher intelligence quotient scores in dietary treated phenylketonuric children. Acta Paediatr 1996; 85:56-8. [PMID: 8834980 DOI: 10.1111/j.1651-2227.1996.tb13890.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Strict control of phenylalanine intake is the main dietary intervention for phenylketonuric children. Whether other dietary-related factors improve the clinical outcome for treated phenylketonuric children in neurodevelopmental terms, however, remains unexplored. We retrospectively compared the intelligence quotient (IQ) score of 26 school-age phenylketonuric children who were either breastfed or formula fed for 20-40 days prior to dietary intervention. Children who had been breastfed as infants scored significantly better (IQ advantage of 14.0 points, p = 0.01) than children who had been formula fed. A 12.9 point advantage persisted also after adjusting for social and maternal education status (p = 0.02). In this sample of early treated term infants with phenylketonuria there was no associated between IQ scores and the age at treatment onset and plasma phenylalanine levels during treatment. We conclude that breastfeeding in the prediagnostic stage may help treated infants and children with phenylketonuria to improve neurodevelopmental performance.
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Affiliation(s)
- E Riva
- Department of Paediatrics, University of Milan Medical School, Italy
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69
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Stemerdink BA, van der Meere JJ, van der Molen MW, Kalverboer AF, Hendrikx MM, Huisman J, van der Schot LW, Slijper FM, van Spronsen FJ, Verkerk PH. Information processing in patients with early and continuously-treated phenylketonuria. Eur J Pediatr 1995; 154:739-46. [PMID: 8582426 DOI: 10.1007/bf02276719] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
UNLABELLED A total of 33 patients with early and continuously-treated phenylketonuria (PKU) between 7 and 16 years of age and 33 matched controls participated in a study examining perceptual, central, and response-related mechanisms of information processing. The specific mechanisms studied were: perceptual filtering, memory search, response selection, response execution, and motor presetting. In addition, groups were compared on mean intelligence level and task oriented behaviour. The performance of the PKU patients practically matched that of the controls on all three tasks, suggesting that PKU patients who are continuously maintained on a well-controlled phenylalanine-restricted diet are not impaired in the elementary mechanisms of information processing. Furthermore, groups did not differ in mean IQ or task-oriented behaviour. CONCLUSION These results underline the importance of continued, well-controlled dietary treatment. Further studies are recommended to obtain a more complete evaluation of the potential of PKU patients under these stricter dietary treatment conditions.
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Affiliation(s)
- B A Stemerdink
- Department of Developmental and Experimental Clinical Psychology, State University Groningen, The Netherlands
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70
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Abstract
Ten different indices of dietary control (IDCs) applied frequently to investigate compliance of phenylketonuric patients were calculated for a set of blood phenylalanine levels for 98 patients in the German Collaborative Study of Children Treated for Phenylketonuria during their first 9 years of life. The results were compared for similarities and differences. Cluster analysis of longitudinal phenylalanine data was introduced to analyse phenylalanine blood levels independent of a priori defined criteria of classification. Three groups of good, intermediate and poor long-term dietary control were identified. Internal validation of the IDCs was corroborated by the high inter-correlations of the indices. External validity was determined by the inter-relations of the WISC-R IQ and the IDCs. The different algorithms of IDCs suggest different clinical conclusions. To facilitate comparisons of results of future research, IDCs should be standardized.
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Affiliation(s)
- A Rupp
- Department of Pediatrics, University of Heidelberg, Germany
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71
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Smith I. Treatment of phenylalanine hydroxylase deficiency. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 1994; 407:60-5. [PMID: 7766961 DOI: 10.1111/j.1651-2227.1994.tb13453.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In phenylalanine hydroxylase deficiency detected by screening treatment in early life, both age at start of treatment and phenylalanine control during treatment are the major determinants of eventual psychological status. The influence of phenylalanine control declines with age but executive performance is influenced by hyperphenylalaninaemia at all ages. In a few subjects neurological deterioration has been reported years after relaxing or stopping treatment. MRI changes in brain white matter are present in most subjects no longer on a strict diet. These changes are usually reversible and closely related to phenylalanine status at the time of investigation. Whether or not the changes point to a specific vulnerability of white matter remains uncertain, although MRI changes were particularly prominent in subjects with neurological disability and may be irreversible in such subjects. Policies on treatment have to take account of these findings.
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Affiliation(s)
- I Smith
- Medical Unit, Institute of Child Health, London, UK
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72
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Stemerdink BA, van der Molen MW, Kalverboer AF, van der Meere JJ, Hendrikx MM, Huisman J, van der Schot LW, Slijper FM. Information processing deficits in children with early and continuously treated phenylketonuria? ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 1994; 407:106-7. [PMID: 7766942 DOI: 10.1111/j.1651-2227.1994.tb13466.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Thirty-three patients with early and continuously treated classical phenylketonuria (PKU) and 33 controls matched for age, gender, and educational level of both parents, participated in a chronometric study exploring elementary mechanisms of information processing. Subjects performed speeded performance tasks designed to systematically vary the load on perceptual, central, and output-related mechanisms of information processing. A preliminary analysis of the data indicated that the overall performance of patients with early and continuously treated PKU practically matched that of the controls on all three tasks. Although this finding must be interpreted with caution as it is based on only a preliminary analysis of the data, it suggests that PKU patients who are continuously maintained on a well-controlled phenylalanine-restricted diet are not deficient in the elementary mechanisms of processing. Given the more recent findings indicating that young children with early-treated classical PKU have specific cognitive deficits in the executive function skills, despite relatively strict dietary control, the authors suggest that future studies should focus on these higher-order cognitive processes.
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Affiliation(s)
- B A Stemerdink
- Department of Developmental and Experimental Clinical Psychology, State University Groningen, The Netherlands
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Recommendations on the dietary management of phenylketonuria. Report of Medical Research Council Working Party on Phenylketonuria. Arch Dis Child 1993; 68:426-7. [PMID: 8466250 PMCID: PMC1793880 DOI: 10.1136/adc.68.3.426] [Citation(s) in RCA: 205] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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