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Manti F, Nardecchia F, Paci S, Chiarotti F, Carducci C, Carducci C, Dalmazzone S, Cefalo G, Salvatici E, Banderali G, Leuzzi V. Predictability and inconsistencies in the cognitive outcome of early treated PKU patients. J Inherit Metab Dis 2017; 40:793-799. [PMID: 28836033 DOI: 10.1007/s10545-017-0082-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 08/03/2017] [Accepted: 08/03/2017] [Indexed: 01/30/2023]
Abstract
Long-term cognitive outcome and treatment of adult early treated (ET)PKU patients is a main issue in PKU research. We questioned whether the intellectual development of ETPKU patients is stable and to what extent its variation may be predicted by the quality of metabolic control. The aims of the present longitudinal retrospective study were to assess in young adult ETPKU patients: i) the relationship between IQ and metabolic control during the first two decades of life; and ii) the intra- and interindividual variability in the developmental trajectory which cannot be predicted by the disease's biomarkers. We collected biochemical data from 65 ETPKU patients (diagnostic blood Phe > 360 μmol/l) who were assessed twice for IQ (Wechsler Intelligence Scale) during their lifetime (mean age: 10.2 and 19.6 years, respectively). Results show that in ETPKU patients IQ over the second decade of life remained stable in about half of the patients (51%); while the rest experienced a gain (7 to 15 points) or loss (7 to 28 points) in IQ scores (23 and 26% respectively) whatever the quality of metabolic control was. The main factor affecting the second IQ was the value of the first IQ (p < 0.000) whose effect overruled that of the markers of metabolic control. Looking at the developmental trajectory of our ETPKU patients, the present study disclosed a remarkable interindividual variability in their cognitive outcome and also an inconsistent linkage between cognitive performances and biochemical control, thus supporting the hypothesis of an individual resilience or vulnerability to Phe in young adult ETPKU.
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Affiliation(s)
- Filippo Manti
- Department of Pediatrics and Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185, Rome, Italy
| | - Francesca Nardecchia
- Department of Pediatrics and Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185, Rome, Italy
| | - Sabrina Paci
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Via Antonio Di Rudinì 8, 20142, Milan, Italy
| | - Flavia Chiarotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Claudia Carducci
- Department of Experimental Medicine, Sapienza University of Rome, Viale del Policlinico 155, 00161, Rome, Italy
| | - Carla Carducci
- Department of Experimental Medicine, Sapienza University of Rome, Viale del Policlinico 155, 00161, Rome, Italy
| | - Silvia Dalmazzone
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Via Antonio Di Rudinì 8, 20142, Milan, Italy
| | - Graziella Cefalo
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Via Antonio Di Rudinì 8, 20142, Milan, Italy
| | - Elisabetta Salvatici
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Via Antonio Di Rudinì 8, 20142, Milan, Italy
| | - Giuseppe Banderali
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Via Antonio Di Rudinì 8, 20142, Milan, Italy
| | - Vincenzo Leuzzi
- Department of Pediatrics and Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185, Rome, Italy.
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Waisbren SE, Prabhu SP, Greenstein P, Petty C, Schomer D, Anastasoaie V, Charette K, Rodriguez D, Merugumala S, Lin AP. Improved Measurement of Brain Phenylalanine and Tyrosine Related to Neuropsychological Functioning in Phenylketonuria. JIMD Rep 2016; 34:77-86. [PMID: 27677920 DOI: 10.1007/8904_2016_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 07/25/2016] [Accepted: 08/25/2016] [Indexed: 12/05/2022] Open
Abstract
INTRODUCTION Researchers hypothesized that in phenylketonuria (PKU) high brain phenylalanine (Phe) levels and low brain tyrosine (Tyr) levels affect neuropsychological functioning. However, traditional magnetic resonance spectroscopy (MRS) yielded uncertain results of brain Phe and could not adequately measure brain Tyr. This pilot study examined the potential of correlated spectroscopy (COSY) to quantify these biomarkers and explain variability in neuropsychological functioning. METHODS Nine adults with early treated classic PKU received magnetic resonance imaging (MRI) with COSY and a battery of neuropsychological tests. Brain Phe and Tyr in parietal white matter (PWM) were compared to results in gray matter of the posterior cingulate gyrus (PCG). RESULTS Brain Phe ranged from 101 to 182 (mean = 136.76 ± 23.77) μmol/L in PCG and 76 to 185 (mean = 130.11 ± 37.88) μmol/L in PWM. Brain Tyr ranged from 4.0 to 7.4 (mean = 5.44 ± 1.01) μmol/L in PCG and 4.1 to 8.4 (mean = 5.90 ± 1.48) μmol/L in PWM. Correlation coefficients were largest for brain Phe PWM and measures of auditory memory (rho = -0.79), anxiety (rho = 0.79), and executive functioning (rho = 0.69). Associations were in the expected direction, with higher brain Phe and lower brain Tyr related to poorer functioning. The two participants with severe structural MRI abnormalities had low brain Tyr levels in PCG and 3/5 of the participants with moderate to severe MRI abnormalities had higher than average brain Phe levels. CONCLUSION COSY has the potential to quantify brain Phe and Tyr at low concentrations and in specific brain regions. In this pilot study, these biomarkers were associated with indices of neuropsychological functioning. Additional studies are needed to validate the COSY results.
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Affiliation(s)
- Susan E Waisbren
- Boston Children's Hospital, 1 Autumn Street, #525, Boston, MA, 02115, USA. .,Harvard Medical School, Boston, MA, USA.
| | - Sanjay P Prabhu
- Boston Children's Hospital, 1 Autumn Street, #525, Boston, MA, 02115, USA
| | - Patricia Greenstein
- Harvard Medical School, Boston, MA, USA.,Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Carter Petty
- Boston Children's Hospital, 1 Autumn Street, #525, Boston, MA, 02115, USA
| | - Donald Schomer
- Harvard Medical School, Boston, MA, USA.,Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Vera Anastasoaie
- Boston Children's Hospital, 1 Autumn Street, #525, Boston, MA, 02115, USA
| | - Kalin Charette
- Boston Children's Hospital, 1 Autumn Street, #525, Boston, MA, 02115, USA
| | | | | | - Alexander P Lin
- Harvard Medical School, Boston, MA, USA.,Brigham and Women's Hospital, Boston, MA, USA
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3
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Grosse SD. Late-Treated Phenylketonuria and Partial Reversibility of Intellectual Impairment. Child Dev 2010; 81:200-11. [DOI: 10.1111/j.1467-8624.2009.01389.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ki CS, Kim JK. A case of two sisters births from mother with phenylketonuria lacking mental retardation. KOREAN JOURNAL OF PEDIATRICS 2008. [DOI: 10.3345/kjp.2008.51.5.546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Chang-Seok Ki
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sung Kyun Kwan University School of Medicine, Korea
| | - Jin Kyung Kim
- Department of Pediatrics, College of Medicine, Daegu Catholic University, Daegu, Korea
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Yalaz K, Vanli L, Yilmaz E, Tokatli A, Anlar B. Phenylketonuria in pediatric neurology practice: a series of 146 cases. J Child Neurol 2006; 21:987-90. [PMID: 17092471 DOI: 10.1177/08830738060210111401] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The neurologic manifestations of patients with phenylketonuria treated at different ages are illustrated in this series of 146 cases, including 9 sib pairs. In addition to well-known findings such as mental retardation, autistic features, microcephaly, and tremor, motor retardation was common and responded promptly to dietary treatment. Hypotonia and diminished reflexes were more frequent findings than hypertonia. Four sib pairs showed divergent features, such as the later-treated sibling having higher function than the early-treated one. Because siblings have a similar genotype and similar environmental and dietary conditions, this observation can be explained by differences in phenylalanine transport to the brain or additional metabolic or perinatal factors influencing the neurologic outcome.
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Møller LB, Paulsen M, Koch R, Moats R, Guldberg P, Güttler F. Inter-individual variation in brain phenylalanine concentration in patients with PKU is not caused by genetic variation in the 4F2hc/LAT1 complex. Mol Genet Metab 2005; 86 Suppl 1:S119-23. [PMID: 16176881 DOI: 10.1016/j.ymgme.2005.07.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Revised: 07/15/2005] [Accepted: 07/25/2005] [Indexed: 11/27/2022]
Abstract
It remains a question why some patients with phenylketonuria (PKU) have high IQ and low brain phenylalanine (Phe) concentrations in spite of high blood Phe levels. One possible explanation for the low brain Phe concentrations in these patients would be a reduced transport of Phe across the blood-brain barrier. The 4F2hc/LAT1 complex has been suggested to be the most important molecular component responsible for this transport. To test the hypothesis that structural variant(s) in the genes encoding 4F2hc and LAT1 might result in a complex with reduced affinity for Phe, we have screened the two genes for sequence variants in a group of 13 PKU patients with a low ratio of brain to blood Phe concentrations. Several common sequence variants were identified, but none of these is predicted to affect the resulting protein product. Our data suggest that individual vulnerability to Phe in patients with PKU is not due to structural variants in the 4F2hc/LAT1 complex.
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Abstract
Newborn screening for phenylketonuria began 35 to 40 years ago in most industrialized countries. Because of this initiative, which resulted in early institution of phenylalanine-restricted diets, there are now many young adults with this disease who have normal or near-normal intellectual function. In North America alone, 200 patients with phenylketonuria enter adulthood every year. Most expert panels recommend following a phenylalanine-restricted "diet for life." However, there are few adult physicians dedicated to continuing care of this group, with the possible exception of maternal phenylketonuria. Up to 10% of adults with classic phenylketonuria, and possibly 50% of those with milder variants, may not need treatment; after adolescence, intelligence does not appear to deteriorate, at least into early adulthood, even if diet therapy is discontinued or not in good control. However, neuropsychological and psychosocial problems develop frequently, needing focused and intensive support by health care providers. New investigative methods and treatment options are on the horizon. There is an urgent need for physicians who will orchestrate the care of adults with phenylketonuria.
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Affiliation(s)
- W B Hanley
- Phenylketonuria Programme, Division of Clinical and Biochemical Genetics, Department of Pediatrics and the Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
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8
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Kahler SG, Fahey MC. Metabolic disorders and mental retardation. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2003; 117C:31-41. [PMID: 12561056 DOI: 10.1002/ajmg.c.10018] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The metabolic and anatomical substrate of most forms of mental retardation is not known. Because the basis of normal brain function is not sufficiently understood, the basis of abnormal function is understood poorly. Even in disorders where the fundamental biochemical defect is known, such as phenylketonuria (PKU) and other enzyme defects, the exact basis for brain dysfunction is uncertain. The outcome for treated PKU, galactosemia, homocystinuria, and lysosomal disorders is not yet optimal. The various forms of nonketotic hyperglycinemia often respond poorly to current therapy. Less familiar disorders, with or without seizures, such as deficient synthesis of serine or creatine and impaired glucose transport into the brain, and disorders with variable malformations, such as Smith-Lemli-Opitz (SLO) syndrome and the congenital disorders of glycosylation (CDGs), may initially be thought to be a nonspecific form of developmental delay. Less familiar disorders, with or without seizures and disorders with variable malformations may initially be thought to be a nonspecific form of developmental delay. Simple tests of urine, blood, and cerebrospinal fluid may lead to a diagnosis, accurate genetic counseling, and better treatment. Metabolic brain imaging (magnetic resonance spectroscopy (MRS)) has also helped to reveal biochemical abnormalities within the brain.
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Affiliation(s)
- Stephen G Kahler
- Genetic Health Services, Victoria/Murdoch Children's Research Institute, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia.
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10
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Abstract
Screening of newborn infants for genetic disease began over 35 years ago as a public health measure to prevent mental retardation in phenylketonuria (PKU). It was so successful that tests for several other genetic disorders were added. We review the current status of this screening, including discussions of the genetic disorders often covered and the results of newborn screening for them. We emphasize recent advances. These include expansion of coverage for genetic disorders with the new methodology of tandem mass spectrometry (MS-MS) and the introduction of molecular (DNA) testing to increase the specificity of testing for several disorders, thereby reducing false-positive rates. These and other advances have also produced issues of criteria for screening, missed cases, and appropriate use of stored newborn specimens.
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Affiliation(s)
- H L Levy
- Genetic Service, Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.
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11
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Weglage J, Wiedermann D, Denecke J, Feldmann R, Koch HG, Ullrich K, Harms E, Möller HE. Individual blood-brain barrier phenylalanine transport determines clinical outcome in phenylketonuria. Ann Neurol 2001; 50:463-7. [PMID: 11601498 DOI: 10.1002/ana.1226] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Different clinical outcomes in spite of comparable dietary controls are well known in patients with phenylketonuria. Currently, reasons for this phenomenon are unknown. Kinetic investigations in 15 patients with classic phenylketonuria were performed using in vivo nuclear magnetic resonance spectroscopy before and after an oral phenylalanine load (100 mg/kg body weight). Patients' brain phenylalanine concentrations were quite different in spite of similar blood phenylalanine levels. Interindividual variations of the apparent transport Michaelis constant, K(t,app), covered a range from 0.10 to 1.03 mmol/L. The ratio of the maximal transport velocity, Tmax, over the intracerebral consumption rate, Vmet, varied between 2.61 and 14.0. Both parameters as well as the preload brain phenylalanine levels correlated significantly with the degree of cerebral white matter abnormalities on magnetic resonance images. Correlations of K(t,app), Tmax/Vmet, and the preload brain phenylalanine levels with patients' intelligence scores approached significance. In conclusion, blood-brain barrier phenylalanine transport characteristics and the resultant brain phenylalanine levels seem to be causative factors for the individual clinical outcome in phenylketonuria. This observation may lead to individual dietary recommendations in the future.
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Affiliation(s)
- J Weglage
- Department of Pediatrics, University of Münster, Germany.
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12
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Abstract
Genetics is affecting all of health care, including nursing. The way in which nurses think about planning health care must be seen now through a "genetic eye" or lens, and nurses must learn to "think genetically." While efforts to integrate genetics into nursing began in earnest in the early 1980s, this effort did not accelerate until the mid-1990s. Before nursing can fully incorporate genetic knowledge into education and practice in a meaningful way, the ways in which genetics will influence health care must be understood. The basic knowledge, skills, and attitudes needed by health professionals are discussed as well as their integration into education and practice. Opportunities for nursing research in genetics are presented as are possible directions. Recommendations for facilitating the integration of genetics into nursing education, practice, and research are also presented.
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Affiliation(s)
- F R Lashley
- School of Nursing, Southern Illinois University Edwardsville, IL 62026-1066, USA.
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