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Liemburg GB, Huijbregts SCJ, Rutsch F, Feldmann R, Jahja R, Weglage J, Och U, Burgerhof JGM, van Spronsen FJ. Metabolic control during the neonatal period in phenylketonuria: associations with childhood IQ. Pediatr Res 2022; 91:874-878. [PMID: 34497359 DOI: 10.1038/s41390-021-01728-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/13/2021] [Accepted: 07/09/2021] [Indexed: 01/26/2023]
Abstract
BACKGROUND In phenylketonuria, treatment and subsequent lowering of phenylalanine levels usually occur within the first month of life. This study investigated whether different indicators of metabolic control during the neonatal period were associated with IQ during late childhood/early adolescence. METHODS Overall phenylalanine concentration during the first month of life (total "area under the curve"), proportion of phenylalanine concentrations above upper target level (360 μmol/L) and proportion below lower target level (120 μmol/L) during this period, diagnostic phenylalanine levels, number of days until phenylalanine levels were <360 μmol/L, and lifetime and concurrent phenylalanine levels were correlated with IQ scores of 64 PKU patients (mean age 10.8 years, SD 2.9). RESULTS Overall phenylalanine concentration and proportion of phenylalanine concentrations >360 μmol/L during the first month of life negatively correlated with IQ in late childhood/early adolescence. Separately, phenylalanine concentrations during different periods within the first month of life (0-10 days, 11-20 days, 21-30 days) were negatively correlated with later IQ as well, but correlation strengths did not differ significantly. No further significant associations were found. CONCLUSIONS In phenylketonuria, achievement of target-range phenylalanine levels during the neonatal period is important for cognition later in life, also when compared to other indicators of metabolic control. IMPACT In phenylketonuria, it remains unclear during which age periods or developmental stages metabolic control is most important for later cognitive outcomes. Phenylalanine levels during the neonatal period were clearly and negatively related to later IQ, whereas no significant associations were observed for other indices of metabolic control. This emphasizes the relative importance of this period for cognitive development in phenylketonuria. No further distinctions were observed in strength of associations with later IQ between different indicators of metabolic control during the neonatal period. Thus, achievement of good metabolic control within 1 month after birth appears "safe" with respect to later cognitive outcomes.
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Affiliation(s)
- Geertje B Liemburg
- Division of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Stephan C J Huijbregts
- Department of Clinical Child and Adolescent Studies/Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands.
| | - Frank Rutsch
- Department of Pediatrics, Münster University, University Children's Hospital, Münster, Germany
| | - Reinhold Feldmann
- Department of Pediatrics, Münster University, University Children's Hospital, Münster, Germany
| | - Rianne Jahja
- Division of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Josef Weglage
- Department of Pediatrics, Münster University, University Children's Hospital, Münster, Germany
| | - Ulrike Och
- Department of Pediatrics, Münster University, University Children's Hospital, Münster, Germany
| | - Johannes G M Burgerhof
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Francjan J van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Ilgaz F, Pinto A, Gökmen-Özel H, Rocha JC, van Dam E, Ahring K, Bélanger-Quintana A, Dokoupil K, Karabulut E, MacDonald A. Long-Term Growth in Phenylketonuria: A Systematic Review and Meta-Analysis. Nutrients 2019; 11:E2070. [PMID: 31484352 PMCID: PMC6769966 DOI: 10.3390/nu11092070] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 12/25/2022] Open
Abstract
There is an ongoing debate regarding the impact of phenylketonuria (PKU) and its treatment on growth. To date, evidence from studies is inconsistent, and data on the whole developmental period is limited. The primary aim of this systematic review was to investigate the effects of a phenylalanine (Phe)-restricted diet on long-term growth in patients with PKU. Four electronic databases were searched for articles published until September 2018. A total of 887 results were found, but only 13 articles met eligibility criteria. Only three studies had an adequate methodology for meta-analysis. Although the results indicate normal growth at birth and during infancy, children with PKU were significantly shorter and had lower weight for age than reference populations during the first four years of life. Impaired linear growth was observed until the end of adolescence in PKU. In contrast, growth impairment was not reported in patients with mild hyperphenylalaninemia, not requiring dietary restriction. Current evidence indicates that even with advances in dietary treatments, "optimal" growth outcomes are not attained in PKU. The majority of studies include children born before 1990s, so further research is needed to show the effects of recent dietary practices on growth in PKU.
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Affiliation(s)
- Fatma Ilgaz
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Hacettepe University, 06080 Ankara, Turkey.
| | - Alex Pinto
- Department of Dietetics, Birmingham Children's Hospital, Birmingham B4 6NH, UK
| | - Hülya Gökmen-Özel
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Hacettepe University, 06080 Ankara, Turkey
| | - Julio César Rocha
- Center for Health Technology and Services Research (CINTESIS), 4200-450 Porto, Portugal
- Centro de Genética Médica Dr Jacinto de Magalhães, Centro Hospitalar Universitário do Porto, 4099-028 Porto, Portugal
- Centro de Referência na área das Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHP EPE, 4099-001 Porto, Portugal
| | - Esther van Dam
- Beatrix Children's Hospital, University of Groningen, University Medical Center, 9700 RB Groningen, The Netherlands
| | - Kirsten Ahring
- Department of PKU, Kennedy Centre, 2600 Glostrup, Denmark
| | | | - Katharina Dokoupil
- Department of Metabolism and Nutrition, Dr. von Hauner Children's Hospital, University of Munich, 80337 Munich, Germany
| | - Erdem Karabulut
- Faculty of Medicine, Department of Biostatistics, Hacettepe University, 06080 Ankara, Turkey
| | - Anita MacDonald
- Department of Dietetics, Birmingham Children's Hospital, Birmingham B4 6NH, UK
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New insights in growth of phenylketonuric patients. Eur J Pediatr 2015; 174:651-9. [PMID: 25367055 DOI: 10.1007/s00431-014-2446-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/14/2014] [Accepted: 10/20/2014] [Indexed: 10/24/2022]
Abstract
UNLABELLED Treatment of phenylketonuria involves a restriction in the intake of natural proteins. This can lead to growth impairment. Weight, height and body mass index of 109 hyperphenylalaninemic patients (mild hyperphenylalaninemia (HPA) and phenylketonuria (PKU)) were determined from birth until 18 years, every 6 months, and differences to the healthy population, depending on the age, sex and phenotype, were analyzed. Data collection was longitudinal retrospective during 31 years. Statistical analysis of z-score values was performed by advanced statistical tools. Long-term evolution of anthropometric z-scores showed no significant statistical differences between PKU and mild HPA individuals, according to the general population. For PKU individuals, height is slightly lower and weight slightly higher than in the healthy population, but differences are smaller than one standard deviation. Nevertheless, over-time evolutions of female height z-scores are different in each type of pathology, with a crossover between 8 and 12 years (p = 0.0186). CONCLUSIONS It is nowadays possible to achieve a long-term normal growth in PKU patients with appropriate dietary treatment. There is however an acceleration of growth up to 8 years old for PKU female patients that leads to a slightly lower final height. Detection of this behaviour was possible by using nonlinear mixed effects models.
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Koura HM, Abdallah Ismail N, Kamel AF, Ahmed AM, Saad-Hussein A, Effat LK. A long-term study of bone mineral density in patients with phenylketonuria under diet therapy. Arch Med Sci 2011; 7:493-500. [PMID: 22295034 PMCID: PMC3258737 DOI: 10.5114/aoms.2011.23417] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 11/10/2010] [Accepted: 12/05/2010] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Dietary control of classic phenylketonuria (PKU) needs restriction of natural proteins; adequate protein intake is achieved by adding low phenylalanine (phe) formulae. The adequacy of this diet for normal bone mineralization had not been sufficiently evaluated. Our aim was to evaluate and follow up bone mineral density (BMD) in children and adolescents with PKU within a 2-year time interval to assess the adequacy of a phenylalanine restricted diet for bone mineralization and to search for a possible relationship between BMD, dietary control and blood phenylalanine (phe) concentrations. MATERIAL AND METHODS Thirty-two patients with classic PKU (3-19 years) were evaluated for their bone mineral status using dual energy X-ray absorptiometry (DEXA) both at the beginning (baseline) and the end (follow-up) of the study. RESULTS Low BMD was detected in 31.25% at the start and in 6.25% of patients after 2 years follows-up. No relationship was found between BMD and the duration of diet compliance and phe level as well. CONCLUSIONS In this study the low BMD detected in our patients was both at baseline and follow-up independent of diet restriction. A yearly DEXA would be highly beneficial for early detection and treatment, thus preventing osteoporosis and decreasing the risk of fractures. We also suggest the importance of searching for new emerging therapies such as enzyme substitution or gene therapy as low protein diet compliance was not enough to maintain normal bone mineral density.
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Affiliation(s)
- Hala M. Koura
- Department of Pediatric, National Research Centre, Cairo, Egypt
| | | | - Ashraf F. Kamel
- Department of Pediatric, National Research Centre, Cairo, Egypt
| | - Azza M Ahmed
- Department of Pediatric, National Research Centre, Cairo, Egypt
| | - Amal Saad-Hussein
- Department of Environmental Research, National Research Centre, Cairo, Egypt
| | - Laila K. Effat
- Department of Molecular Genetic, National Research Centre, Cairo, Egypt
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Demirkol M, Giżewska M, Giovannini M, Walter J. Follow up of phenylketonuria patients. Mol Genet Metab 2011; 104 Suppl:S31-9. [PMID: 22018725 DOI: 10.1016/j.ymgme.2011.08.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/31/2011] [Accepted: 08/07/2011] [Indexed: 11/26/2022]
Abstract
In recent years our understanding of the follow up policies for PKU has increased substantially. In particular, we now understand the importance of maintaining control of blood phenylalanine (phe) concentrations life-long to achieve the best long-term neuropsychological outcomes. The concordance with the follow up strategy remains a key challenge for the future, especially with respect to adolescents and young adults. The recent therapies could ease the burden of the dietary phe restriction for PKU patients and their families. The time may be right for revisiting the guidelines for follow up of PKU in order to address a number of important issues related to PKU management: promotion of breastfeeding to complementary feeding up to 2 years of age for prevention of early growth retardation and later overweight development, treatment advancements for metabolic control, blood phe and tyr variability, routine screening measures for nutritional biomarkers, neurocognitive and psychological assessments, bone pathology, understanding the challenges of compliance and transitioning into adulthood as an individual with PKU and addressing unmet needs in this population.
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Affiliation(s)
- M Demirkol
- Div Nutrition and Metabolism, Children's Hospital, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey.
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REFERENCES. Monogr Soc Res Child Dev 2008. [DOI: 10.1111/j.1540-5834.1997.tb00532.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Huemer M, Huemer C, Möslinger D, Huter D, Stöckler-Ipsiroglu S. Growth and body composition in children with classical phenylketonuria: results in 34 patients and review of the literature. J Inherit Metab Dis 2007; 30:694-9. [PMID: 17628756 DOI: 10.1007/s10545-007-0549-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 04/30/2007] [Accepted: 05/03/2007] [Indexed: 10/23/2022]
Abstract
Treatment of phenylketonuria (PKU, OMIM 261600) means a diet restricted in natural protein and supplemented with phenylalanine (Phe)-free L-amino acid mixtures. Growth impairment has been described even in patients with a total protein intake at or above the recommended dietary allowance (RDA). In the present study, growth and body composition (fat-free mass (FFM) and fat) were recorded over 12 months in 34 treated PKU patients (mean age 8.7 years at baseline). Measurements were compared with those of healthy peers and with general population standard (Z-) scores calculated using the LMS method. In 28 PKU patients, data on birth weight and birth length were available and related to measurements at baseline of the study. Mean total protein intake in PKU patients was 124% (range 77-193%) of the RDA (DACH 2000). No significant differences in growth and body composition were present between PKU patients and healthy populations either at birth or during the study period. The significant correlation of FFM (representing muscle mass) with intake of natural protein--rather than total protein--indicates that the enhancement of tolerance to natural protein may be of value in PKU patients.
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Affiliation(s)
- M Huemer
- Department of Pediatrics, Landeskrankenhaus Bregenz, Carl Pedenz Str. 2, 6900, Bregenz, Austria.
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Waisbren SE, Noel K, Fahrbach K, Cella C, Frame D, Dorenbaum A, Levy H. Phenylalanine blood levels and clinical outcomes in phenylketonuria: a systematic literature review and meta-analysis. Mol Genet Metab 2007; 92:63-70. [PMID: 17591452 DOI: 10.1016/j.ymgme.2007.05.006] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Revised: 05/10/2007] [Accepted: 05/10/2007] [Indexed: 12/21/2022]
Abstract
Blood phenylalanine (Phe) levels provide a practical and reliable method for the diagnosis and monitoring of metabolic status in patients with phenylketonuria (PKU). To assess the reliability of blood Phe levels as a predictive biomarker of clinical outcomes in the development of treatments for PKU, a systematic literature review and meta-analysis of published trials of PKU, which included Phe level and neurological and dietary compliance outcome measures, was conducted. Within-study correlations between Phe level and intelligence quotient (IQ) were extracted from 40 studies. Significant, proportional correlations were found during critical periods (from 0 to 12 years of age) for early-treated patients with PKU (r=-0.35; 95% confidence interval [CI]: -0.44 to -0.27), where each 100 micromol/l increase in Phe predicted a 1.3- to 3.1-point reduction in IQ. Similar significant correlations were observed between IQ and mean lifetime Phe level for early-treated patients (r=0.34; 95% CI: -0.42 to -0.25), where each 100 micromol/l increase in Phe predicted a 1.9- to 4.1-point reduction in IQ. Moderate correlations were found between concurrent Phe level and IQ for early-treated patients. In conclusion, these results confirm a significant correlation between blood Phe level and IQ in patients with PKU, and support the use of Phe as a predictive biomarker for IQ in clinical trials.
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Affiliation(s)
- Susan E Waisbren
- Children's Hospital Boston, 1 Autumn Street, Room 525, Boston, MA 02115, USA.
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Giovannini M, Verduci E, Salvatici E, Fiori L, Riva E. Phenylketonuria: dietary and therapeutic challenges. J Inherit Metab Dis 2007; 30:145-52. [PMID: 17347911 DOI: 10.1007/s10545-007-0552-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 01/31/2007] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
PKU subjects need special attention in the definition of optimal supplementation of nutrients, which may be insufficient in relation to the type of diet and may otherwise manifest symptoms of deficit. In particular, it is necessary to pay great attention to the long-chain polyunsaturated fatty acid (LC-PUFA) levels in relation to correct development of the central nervous system. On the basis of numerous beneficial effects currently known, a permanent supplementation with LC-PUFAs, in particular with docosahexaenoic acid, should be considered. Moreover, new formulas, Phe-free peptides, and 'modulated' amino acid preparations might help in preventing nutritional deficiencies and imbalances, with the ultimate aim of improving growth. New strategies--such as supply of tetrahydrobiopterin--need to be optimized in terms of targets, patients and expected outcomes.
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Affiliation(s)
- M Giovannini
- Department of Pediatrics, San Paolo Hospital, University of Milan, Milan, Italy.
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Loots DT, Mienie LJ, Erasmus E. Amino-acid depletion induced by abnormal amino-acid conjugation and protein restriction in isovaleric acidemia. Eur J Clin Nutr 2007; 61:1323-7. [PMID: 17299485 DOI: 10.1038/sj.ejcn.1602648] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Previously, we detected 19 'new' amino-acid conjugates in the urine of patients with isovaleric acidemia. There is currently a poor understanding of the relationship between the clinical symptoms and the excreted metabolites occurring in these patients, owing to insufficient metabolite characterization and quantification. Consequently, controversial treatment protocols exist, particularly pertaining to dietary protein restriction. OBJECTIVE To determine the effect of the previously identified amino-acid conjugates and conventional dietary protein restriction therapy, on the free amino-acid concentrations in isovaleric acidemia patients, to better explain the clinical symptoms and develop more effective therapy. DESIGN Free amino-acid quantification via liquid chromatography mass spectrometry (LC-MS-MS) was performed on pre- and post-treatment urine or serum samples collected from six isovaleric acidemia patients, previously investigated for the presence of new induced N-isovaleryl and N-acetyl-amino-acid conjugates. RESULTS Depleted amino-acid concentrations were detected in varying degrees in all six patients and did not recover after conventional treatment. CONCLUSIONS The 19 potentially toxic metabolites previously identified and the consequent amino-acid depletions detected in this study, may explain many of the clinical symptoms associated with isovaleric acidemia. Furthermore, the occurrence of amino-acid depletions in these patients, steers away from the controversial dietary protein restriction treatment protocols, and towards dietary leucine restriction alone with essential amino-acid supplementation, in combination with glycine and L-carnitine supplementation.
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Affiliation(s)
- D T Loots
- Department of Nutrition, School of Physiology, Nutrition and Consumers Science, Potchefstroom, South Africa.
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Dobbelaere D, Michaud L, Debrabander A, Vanderbecken S, Gottrand F, Turck D, Farriaux JP. Evaluation of nutritional status and pathophysiology of growth retardation in patients with phenylketonuria. J Inherit Metab Dis 2003; 26:1-11. [PMID: 12872834 DOI: 10.1023/a:1024063726046] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent European studies have shown that growth retardation is com-mon in people with phenylketonuria (PKU) during the first years of life while they receive a low-phenylalanine (Phe) diet. The aims of the present study were to assess the growth of our PKU patients and to search for nutritional and hormonal explanations for the growth delay. Twenty PKU patients aged 8 months to 7 years entered the study. The design was cross-sectional, a longitudinal study having already been performed in our centre. The following data were recorded: weight/height (W/H), height/age (H/A), and weight/age (W/A) Z-scores; fat-free mass (measured from bioelectrical impedometry (FFM1), and skinfold thickness (FFMA). Thyroid hormones, insulin-like growth factor I (IGF1), insulin-like growth factor binding protein (IGFBP3), selenium, zinc, and Phe blood levels were measured. Dietary intake was also recorded over 4 days. PKU patients were moderately but significantly shorter (H/A Z-score varied from -2.12 to 1.61; mean -0.49) and lighter (W/A Z-score varied from -2.58 to 1.49; mean -0.71) than the French reference population. Body composition was not different from that of controls matched for age and sex. IGF1, IGFBP3, and thyroid hormone levels were within normal range. All children received more than two-thirds of the recommended daily allowances for energy (91% +/- 18%) and for proteins (146% +/- 26%). The mean daily intake of our patients was sufficient in selenium, but markedly deficient in zinc (2.4 +/- 2.2 mg/day). No correlation was found between zinc daily intake or zinc plasma levels and growth retardation. Moreover, no relation was found between the plasma Phe concentrations, protein or caloric intake and the presence of growth retardation. Our results show that growth retardation in PKU patients is not related to hormonal or caloric deficiencies. Further studies are needed to investigate the effect of various nutrient supplementation regimens (especially zinc) on the growth of PKU patients.
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Affiliation(s)
- D Dobbelaere
- Unit of Metabolic Disease, Department of Pediatrics, Lille University Children's Hospital and Faculty of Medicine, Lille, France.
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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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