1
|
Jaulent P, Charriere S, Feillet F, Douillard C, Fouilhoux A, Thobois S. Neurological manifestations in adults with phenylketonuria: new cases and review of the literature. J Neurol 2019; 267:531-542. [PMID: 31701331 DOI: 10.1007/s00415-019-09608-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/24/2019] [Accepted: 10/26/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Phenylketonuria (PKU) is a rare autosomal recessive disease characterised by high plasma phenylalanine levels inducing, if untreated, serious neurological manifestations in children but also, rarely, in adults who stopped their diet. The objective of the study was to describe the neurological manifestations observed in adults with PKU. METHODS We analysed cases reported in French reference centres for inborn errors of metabolism and cases already reported in the literature. RESULTS We report 8 new cases of neurological manifestations and 22 cases in the literature, which occurred in adult PKU patients, associated with chronic or rapid increase of phenylalanine levels, mostly when strict low-phenylalanine diet was stopped early in life. Neurological symptoms consisted in cerebellar ataxia, tremor, brisk reflexes, visual loss, sensory manifestations, and/or headaches. Visual loss was more frequent in the new cases (4/8) of the present series than in the literature (4/22). These neurological complications were associated with leucopathy on brain magnetic resonance imaging (27/29). The start of a low-phenylalanine diet improved or fully reversed neurological manifestations, even in patients with late diagnosis during adulthood. CONCLUSION Neurological manifestations can complicate PKU in adult patients with elevated phenylalanine levels, after long or short period of diet discontinuation. Neurologists should be aware of this diagnosis, and measure phenylalaninemia in case of neurological symptoms associated with non-specific leucopathy on brain MRI. PKU patients should be systematically encouraged to continue their diet and their medical follow-up to avoid neurological complications.
Collapse
Affiliation(s)
- Paul Jaulent
- Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Neurologie C, 69677, Bron Cedex, France
| | - Sybil Charriere
- Hospices Civils de Lyon, Hôpital Cardiovasculaire Louis Pradel, Fédération D'endocrinologie, Maladies métaboliques, diabète Et Nutrition, Groupement Hospitalier Est, 28 avenue Doyen Lépine, 69677, Bron Cedex, France. .,INSERM U1060, Laboratoire Carmen, Université Lyon 1, INRA U1235, INSA de Lyon, 69621, Villeurbanne, France. .,CENS, Centre de Recherche en Nutrition Humaine Rhône Alpes, 69921, Oullins Cedex, France. .,Université Lyon 1 Claude Bernard, Faculté de médecine Lyon EST, 69373, Lyon, France. .,Hospices Civils de Lyon, Centre de référence Des Maladies héréditaires du métabolisme de Lyon, Groupement Hospitalier Est, 69677, Bron Cedex, France.
| | - François Feillet
- CHU de Nancy, Hôpitaux de Brabois, Centre de référence Des Maladies héréditaires du métabolisme de Nancy, 54511, Vandoeuvre-les Nancy, France
| | - Claire Douillard
- Centre Hospitalier Régional Universitaire de Lille, Hopital Claude Huriez, Service D'Endocrinologie-Diabétologie-Métabolisme, Hopital Huriez, 59037, Lille, France
| | - Alain Fouilhoux
- Hospices Civils de Lyon, Centre de référence Des Maladies héréditaires du métabolisme de Lyon, Groupement Hospitalier Est, 69677, Bron Cedex, France
| | - Stéphane Thobois
- Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Neurologie C, 69677, Bron Cedex, France.,Université Lyon 1 Claude Bernard, Faculté de médecine Lyon EST, 69373, Lyon, France.,CNRS, Institut Des Sciences Cognitives Marc Jeannerod, UMR 5229, 69675, Bron, France
| |
Collapse
|
4
|
Abstract
Phenylketonuria, an autosomal recessively transmitted disorder of amino acid metabolism, is caused by a deficiency of hepatic phenylalanine hydroxylase converting phenylalanine to tyrosine. Thus, phenylalanine accumulates to plasma levels exceeding 1200 mumol/l. Untreated phenylketonuria is characterized by microcephaly, epilepsy, severe mental retardation and, in some cases, progressive supranuclear motor disturbances. These symptoms can largely be prevented by the early start of a phenylalanine-restricted diet. Neurological investigations of treated patients reveal only minor neurological signs, such as tremor or brisk deep tendon reflexes. Magnetic resonance imaging shows white matter abnormalities. However, in single patients, progressive neurological symptoms occurred. Thus, the long-term prognosis of treated phenylketonuria is still under discussion.
Collapse
Affiliation(s)
- J Pietz
- Department of Pediatric Neurology, University of Heidelberg, Germany.
| |
Collapse
|
5
|
Fisch RO, Chang PN, Weisberg S, Guldberg P, Güttler F, Tsai MY. Phenylketonuric patients decades after diet. J Inherit Metab Dis 1995; 18:347-53. [PMID: 7474903 DOI: 10.1007/bf00710427] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nineteen early-treated phenylketonuric patients, whose diet was discontinued between 4.5 and 13 years of age, and who have been off the diet for 12-28 years, were reassessed in 1992-93. There was little change in mean IQ between end of diet and follow-up, less than one IQ point on the average, with no change for any individual exceeding 12 IQ points. Both prior and current IQ correlated slightly negatively with mean phenylalanine (Phe) concentration, and positively with parents' education. The phenylalanine level at follow-up was significantly lower on average by about 900 mumol/L. Five of the subjects (26%) have evidence of mental disease. However, the data suggest that the discontinuation of the diet did not cause intellectual deterioration. Nonetheless, the patients' intellect cannot be the only consideration for maintenance of diet. The occurrence of psychopathology among phenylketonuric patients and the possible unknown effects of toxic elevation of phenylalanine during their lifetime suggest the need to maintain the diet. The use of DNA for diagnostic and prognostic purposes might assist in decisions about dietary quality and duration, and in anticipation of psychopathology.
Collapse
Affiliation(s)
- R O Fisch
- Department of Pediatrics, University of Minnesota, Minneapolis 55455, USA
| | | | | | | | | | | |
Collapse
|
6
|
McCombe PA, McLaughlin DB, Chalk JB, Brown NN, McGill JJ, Pender MP. Spasticity and white matter abnormalities in adult phenylketonuria. J Neurol Neurosurg Psychiatry 1992; 55:359-61. [PMID: 1602307 PMCID: PMC489075 DOI: 10.1136/jnnp.55.5.359] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A 19 year old male with phenylketonuria (PKU) developed a spastic paparesis 8 months after stopping his restricted phenylalanine diet. CT and MRI showed abnormalities of the deep cerebral white matter, and visual evoked response latencies were prolonged. The spasticity gradually improved over several months after resuming the PKU diet. A repeat MRI scan was unchanged. His brother also had PKU and ceased dietary restrictions, but his only neurological abnormality was a slight increase in the deep tendon reflexes of the lower limbs. CT and MRI of his brain was normal. DNA analysis showed that both brothers were homozygous for the same PKU mutation. These patients demonstrate that reversible neurological signs may develop in patients with classic PKU after ceasing dietary restrictions and that these may be associated with abnormalities seen on neuro-imaging.
Collapse
Affiliation(s)
- P A McCombe
- Department of Medicine, University of Queensland, Brisbane, Australia
| | | | | | | | | | | |
Collapse
|
7
|
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.
Collapse
|
8
|
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.
Collapse
|
9
|
Smith I, Lobascher ME, Stevenson JE, Wolff OH, Schmidt H, Grubel-Kaiser S, Bickel H. Effect of stopping low-phenylalanine diet on intellectual progress of children with phenylketonuria. BRITISH MEDICAL JOURNAL 1978; 2:723-6. [PMID: 698696 PMCID: PMC1607584 DOI: 10.1136/bmj.2.6139.723] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Forty-seven patients at the Hospital for Sick Children, London, who had phenylketonuria and were on a low-phenylalanine diet (21 early-treated--that is, treatment started before the age of 4 months--and 26 late-treated) were placed on a normal diet between the ages of 5 and 15 years. They showed significant falls in mean IQ of about six points after the diet was withdrawn. Twenty-two similar patients (five early-treated and 17 late-treated) at the Universitäts-Kinderklinik, Heidelberg, who were placed on a relaxed low-phenylalanine rather than a normal diet, showed smaller and non-significant falls in mean IQ. During the period of strict diet none of the patients in London or Heidelberg showed any consistent falls in IQ. These results suggest that complete withdrawal of the low-phenylalanine diet during childhood leads to a fall in intellectual progress in many patients.
Collapse
|