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Berry SA, Brown C, Grant M, Greene CL, Jurecki E, Koch J, Moseley K, Suter R, van Calcar SC, Wiles J, Cederbaum S. Newborn screening 50 years later: access issues faced by adults with PKU. Genet Med 2013; 15:591-9. [PMID: 23470838 PMCID: PMC3938172 DOI: 10.1038/gim.2013.10] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 01/15/2013] [Indexed: 11/09/2022] Open
Abstract
Fifty years after the implementation of universal newborn screening programs for phenylketonuria, the first disease identified through newborn screening and considered a success story of newborn screening, a cohort of adults with phenylketonuria treated from birth provides valuable information about effects of long-term treatment for inborn errors of metabolism in general, and phenylketonuria specifically. For phenylketonuria, newborn screening allows early implementation of the phenylalanine-restricted diet, eliminating the severe neurocognitive and neuromotor impairment associated with untreated phenylketonuria. However, executive function impairments and psychiatric problems are frequently reported even for those treated early and continuously with the phenylalanine-restricted diet alone. Moreover, a large percentage of adults with phenylketonuria are reported as lost to follow-up by metabolic clinics. While a group of experts identified by the National Institutes of Health convenes to update treatment guidelines for phenylketonuria, we explore individual patient, social, and economic factors preventing >70% of adult phenylketonuria patients in the United States from accessing treatment. As more conditions are identified through newborn screening, factors affecting access to treatment grow in importance, and we must continue to be vigilant in assessing and addressing factors that affect patient treatment outcomes and not just celebrate amelioration of the most severe manifestations of disease.
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Affiliation(s)
- Susan A. Berry
- Department of Pediatrics, Division of
Genetics and Metabolism, University of Minnesota, Minneapolis,
Minnesota, USA
| | | | - Mitzie Grant
- Departments of Psychiatry and Pediatrics,
Drexel University College of Medicine, Philadelphia,
Pennsylvania, USA
| | - Carol L. Greene
- Department of Pediatrics, Division of
Genetics, University of Maryland, Baltimore, Maryland,
USA
| | | | | | - Kathryn Moseley
- Department of Pediatrics, Genetics Division,
University of Southern California Keck School of Medicine, Los
Angeles, California, USA
| | - Ruth Suter
- BioMarin Pharmaceutical Inc.,
Novato, California, USA
| | - Sandra C. van Calcar
- Department of Pediatrics and Waisman Center,
University of Wisconsin-Madison, Madison, Wisconsin,
USA
| | - Judy Wiles
- Facet Communications Inc.,
Toronto, Ontario, Canada
| | - Stephen Cederbaum
- Departments of Psychiatry, Pediatrics and
Human Genetics, University of California, Los Angeles, Los Angeles,
California, USA
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Hewitt P, Cottle M, Coleman C. The Long-Term Use of a Low-Phenylalanine Diet in Late-Treated Phenylketonuria: A Single Case Report. JOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES 2006. [DOI: 10.1111/j.1468-3148.2005.00257.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Harvey EL, Kirk SF. The use of a low phenylalanine diet in response to the challenging behaviour of a man with untreated phenylketonuria and profound learning disabilities. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 1995; 39 ( Pt 6):520-526. [PMID: 8746739 DOI: 10.1111/j.1365-2788.1995.tb00572.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
If phenylketonuria (PKU) is not treated from an early age with a reduced phenylalanine diet, irreversible brain damage may occur. Although dietary intervention can do nothing to alter this impairment once it occurs, there is some evidence to suggest that a low phenylalanine diet may help to reduce the level of behavioural disturbances frequently experienced by people with untreated PKU. Using this evidence, dietary intervention was used in response to the challenging behaviour of a 30-year-old man with profound learning disabilities. Initial improvements were observed, but overall the results were inconclusive. Possible confounding factors are discussed. An unusual reaction to neuroleptic medication whilst on the diet is also documented.
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Affiliation(s)
- E L Harvey
- Psychology Services, Bradford Community Health (NHS) Trust, England
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Schuett VE, Brown ES, Michals K. Reinstitution of diet therapy in PKU patients from twenty-two US clinics. Am J Public Health 1985; 75:39-42. [PMID: 3966596 PMCID: PMC1646129 DOI: 10.2105/ajph.75.1.39] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In a nationwide survey we found 72 PKU (phenylketonuria) patients who had terminated diet but later returned to diet. Sixty-one patients resumed diet due to clinical problems. Age at initial diet discontinuation ranged from three to 20 years. The most prevalent problems reported were poor school performance, and mood and/or behavior changes. Following diet reinstitution, only positive changes were noted for 42 patients, no changes for 19 patients, and 11 had one or more negative changes. Improvements and blood phenylalanine levels were not significantly correlated, but only 11 patients maintained levels less than 10 mg/dl. The number of improvements was significantly correlated with length of time on diet (p less than 0.001). After a median of 10 months on diet, 22 patients had again discontinued due to poor diet control, lack of motivation, poor formula tolerance, lack of apparent benefits and/or changes for the worse. Median time on diet for the 50 second-time continuers was two years nine months.
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Schuett VE, Gurda RF, Brown ES. Diet discontinuation policies and practices of PKU clinics in the United States. Am J Public Health 1980; 70:498-503. [PMID: 7377420 PMCID: PMC1619429 DOI: 10.2105/ajph.70.5.498] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Marked diversity in policies and practices for discontinuation of the PKU diet in the U.S. was found in a nationwide survey. Seventy-two of the 78 identified clinical centers treating PKU provided data. No clinicians are currently considering diet discontinuation at ages earlier than their present policy or practice. A definite trend toward later discontinuation of diet was identified. A few clinicians have always recommended indefinite diet continuation while many clinics have experience with children ages 9--12 who have discontinued the diet. Clinics with seven or more children off diet in this age range are significantly more likely than smaller clinics to be considering a later age for diet discontinuation. There were 151 children approximately age 10 or older, who remain on a low phenylalanine diet. These children are followed by 29 clinics, but over one-half of them are followed by five clinics which have had long-standing policies of indefinite diet continuation. Factors associated with success in long-term management are a firm clinic policy supporting continued diet treatment; frequent, supportive contacts with the family; open discussion by staff with families and establishment of a trusting relationship; teaching children to accept responsibility for diet management from an early age.
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Waisbren SE, Schnell RR, Levy HL. Diet termination in children with phenylketonuria: a review of psychological assessments used to determine outcome. J Inherit Metab Dis 1980; 3:149-53. [PMID: 6787336 DOI: 10.1007/bf02312549] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This paper reviews the 19 published studies that have utilized psychological assessments in determining the outcome of children with phenylketonuria who have discontinued a phenylalanine-restricted diet. About half the studies showed that, after diet termination, the intellectual performance of children decreased, while the other studies indicated that the intellectual performance of the children did not change. Difficulties in the use of intelligence tests to answer questions about diet termination are outlined. Due to the methodological difficulties and the varying results reported, the issue concerning the safety of diet discontinuation remains unresolved. The conclusion is that the task now is to differentiate those children who should remain on the diet from those who may safely terminate.
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Abstract
Trends in intellectual functioning before and after diet termination were examined in 30 children with PKU treated before 6 weeks of age and on a liberal diet for a mean of three years since the mean age of 59 months. Comparisons of trends in pre- and posttermination IQ scores with the linear spline technique revealed no significant differences. Comparisons of pretermination IQ scores with posttermination scores and scores from the most recent evaluation also yielded no significant differences. These data fail to support a relationship between termination of diet and impairment of intellectual functioning, at least during this period of observation.
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Holtzman NA, Welcher DW, Mellits ED. Termination of restricted diet in children with phenylketonuria: a randomized controlled study. N Engl J Med 1975; 293:1121-4. [PMID: 1102976 DOI: 10.1056/nejm197511272932204] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This study demonstrates the feasibility of a randomized controlled investigation of terminating the phenylalanine-restricted diet in four-year-old children with phenylketonuria. The parents of 14 of 16 children gave informed consent, knowing their children would be randomly assigned to either a diet-continuation or a diet-termination group. Compared with the continuation group, the mean serum phenylalanine of the termination group was 15.1 mg per dl higher (P less than 0.005) one year, and 9.2 mg per dl higher (P less than 0.025) two years after diet termination. Mean weight gain between four and six years of age was 3.4 kg greater in the terminated than in the continued group (P less than 0.01). There were no significant differences in mean head circumferences, height or performances on psychologic tests. At age six, mean I.Q. in the terminated group was 99.8, in those continuing the diet 103.6. Children in both groups showed some subtest scatter in memory and concentration. Thus, no harmful effects of diet termination were noted, but a longer period of observation in a larger number of subjects is needed.
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