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Rett Syndrome: Investigation of Nine Patients, including PET Scan

Published online by Cambridge University Press:  02 December 2014

Henry G. Dunn ,
A. Jon Stoessl ,
Helena H. Ho ,
Patrick M. MacLeod ,
Kenneth J. Poskitt ,
Doris J. Doudet ,
Michael Schulzer ,
Derek Blackstock ,
Teresa Dobko  and
Ben Koop
...Show all authors
Henry G. Dunn
Affiliation:
From the Division of Neurology, Department of Pediatrics University of Victoria, Victoria, BC Canada.
A. Jon Stoessl
Affiliation:
Department of Medicine/Neurology University of Victoria, Victoria, BC Canada.
Helena H. Ho
Affiliation:
From the Division of Neurology, Department of Pediatrics University of Victoria, Victoria, BC Canada.
Patrick M. MacLeod
Affiliation:
University of British Columbia, Vancouver, BC; Section of Genetics, Department of Laboratory Medicine, Capital Health Region, Victoria, BC University of Victoria, Victoria, BC Canada.
Kenneth J. Poskitt
Affiliation:
Department of Radiology, BC’s Children’s Hospital, Vancouver, BC University of Victoria, Victoria, BC Canada.
Doris J. Doudet
Affiliation:
Department of Medicine/Neurology University of Victoria, Victoria, BC Canada.
Michael Schulzer
Affiliation:
Medicine and Statistics University of Victoria, Victoria, BC Canada.
Derek Blackstock
Affiliation:
Department of Anesthesiology University of Victoria, Victoria, BC Canada.
Teresa Dobko
Affiliation:
UBCTRIUMF PET Program University of Victoria, Victoria, BC Canada.
Ben Koop
Affiliation:
University of British Columbia, Vancouver, BC; Department of Biology University of Victoria, Victoria, BC Canada.
Giovana V. de Amorim
Affiliation:
University of British Columbia, Vancouver, BC; Department of Biology University of Victoria, Victoria, BC Canada.
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Abstract

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Background:

We describe nine females with Rett Syndrome (RS), aged 14 to 26 years. All had had developmental delay before the end of their first year and had subsequently regressed to profound dementia with apraxia, ataxia, irregular respirations and often also seizures.

Methods:

The Revised Gesell developmental assessment and Alpern-Boll Developmental Profile were used in modified form. Volumetric measurements of basal ganglia using MRI were compared with the findings in nine age-matched volunteer females. Positron emission scans with [18F]-6-fluorodopa and [11C]-raclopride were performed under light anesthesia with intravenous Propofol, and the findings were compared with those in healthy control girls. Bidirectional sequencing of the coding regions of the MECP2 gene was investigated in blood samples for mutational analyses.

Results:

The RS females functioned at a mental age level ranging from about 4 to 15 months. The scores correlated with height, weight and head circumference. Magnetic resonance scans of basal ganglia showed a significant reduction in the size of the caudate heads and thalami in the Rett cases. Positron emission scans demonstrated that the mean uptake of fluorodopa in RS was reduced by 13.1% in caudate and by 12.5% in putamen as compared to the controls, while dopamine D2 receptor binding was increased significantly by 9.7% in caudate and 9.6% in putamen. Mutations in the coding regions of the MECP2 gene were present in all nine patients. No significant correlation between type and location of mutation and volumetric changes or isotope uptake was demonstrable.

Conclusion:

Our findings suggest a mild presynaptic deficit of nigrostriatal activity in Rett syndrome.

Résumé:

RÉSUMÉ:Introduction:

Nous décrivons les cas de neuf femmes, âgées de 14 à 26 ans, atteintes du syndrome de Rett (SR). Un retard de développement avait été observé chez toutes avant la fin de leur première année de vie. Toutes avaient régressé par la suite et présentaient une démence profonde avec apraxie, ataxie, respiration irrégulière et, dans plusieurs cas, des crises convulsives.

Méthodes:

Des versions modifiées de l’échelle révisée du développement de Gesell et du profil du développement d’Alpern-Boll ont été utilisées. Des mesures volumétriques des noyaux gris centraux par résonance magnétique ont été comparées à celles faites chez neuf femmes volontaires, appariées pour l’âge. La tomographie par émission de positons (PET scan) au [18F]-6-fluorodopa et au [11C]-raclopride a été effectuée sous anesthésie légère par le Propofol intraveineux et les observations ont été comparées à celles de femmes témoins normales. On a procédé à une analyse mutationnelle par séquençage bidirectionnel des régions codantes du gène MECP2.

Résultats:

Les femmes atteintes du SR fonctionnaient à un niveau d’âge mental de 4 à 15 mois. Les scores étaient corrélés à la taille, au poids et à la circonférence de la tête. La resonance magnétique des noyaux gris centraux a montré une réduction significative de la taille de la tête du noyau caudé et du thalamus chez les cas de SR. Le PET scan a montré que la captation moyenne de fluorodopa dans le SR était réduite de 13,1% dans le noyau caudé et de 12,4% dans le putamen par rapport aux contrôles et que la liaison aux récepteurs dopaminergiques D2 était augmentée significativement de 9,7% dans le noyau caudé et de 9,6% dans le putamen. Des mutations dans les régions codantes du gène MECP2 étaient présentes chez les neuf patientes. Aucune corrélation significative entre le type et le site des mutation et les changements volumétriques ou la captation isotopique n’a pu être démontrée.

Conclusion:

Nos observations suggèrent qu’il existe un léger déficit présynaptique de l’activité nigro-striée dans le SR.

Type
Research Article
Information
Canadian Journal of Neurological Sciences , Volume 29 , Issue 4 , November 2002 , pp. 345 - 357
Copyright
Copyright © The Canadian Journal of Neurological 2002

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