Abstract
In this report, we reviewed the characteristics of motor development and motor symptoms
of Rett Syndrome (RTT) and demarcated the early and pathognomonic motor symptom which
correlates to the impairment of the higher cortical function (HCF) assessed by the
ability of language. It is suggested that failure of locomotion in late infancy is
the primary and pathognomonic symptom. Thus, the impairment of the neurons or neuronal
systems involving locomotion is suggested as the primary lesion in the pathophysiology
of RTT not only for motor dysfunction but also for the failure in the development
of language and cognitive function. On the other hand the neuronal systems involving
the loss of purposeful hand use and the stereotyped hand movement, the most characteristic
and diagnostic symptoms of RTT appearing in early childhood, are affected later or
secondarily but induce further degradation of the HCF. Hypofunction of the aminergic
neurons in the brainstem and midbrain is suggested as the cause of dysfunction of
these neuronal systems, for those of locomotion, the noradrenarlin (NA) and/or the
serotonin (5HT) neurons and for the stereotyped hand movement the dopamine (DA) neurons.
The NA and/or the 5HT neurons in the brain stem may be involved primarily and may
cause dysfunction of the midbrain DA neuron directly or indirectly through affecting
the pedunculopontine nuclei.
Keywords
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References
- Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2.Nat Genet. 1999; 23: 185-188
- Rett syndrome: a suggested staging system for describing impairment profile with increasing age towards adolescence.Am J Med Genet :24 (Suppl. 1986; 1: 47-59
- Anatomy of Rett syndrome.Am J Med Genet. 1986; : 289-303
- Age-related occurrence of signs and symptoms in the Rett syndrome.Brain Dev. 1972; : S11-S20
- Clinical features of the early stage of the Rett syndrome.Brain Dev. 1990; : 16-19
- Locomotion in late infancy and development of higher cortical function at later ages.in: Perat M.V. New Developments in Child Neurology. International Proceedings Division, Monduzzi Editore, Bologna1998: 27-30
- Motor symptoms of the Rett syndrome: abnormal muscle tone, posture, locomotion and stereotyped movement.Brain Dev. 1992; : 14(suppl)S21-14(suppl)S28
- Rett syndrome clinical studies and pathophysiological consideration.Brain Dev. 1984; : 475-486
- The function of long propriospinal pathways in the co-ordination of quadrupedal stepping in the cat.in: Stein R.B. Pearson K.G. Smith R.S. Redford J.B. Control of posture and locomotion (Advances in Behavioral Biology Vol. 7). Plenum Press, New York1973: 561-577
- Neuronal constituents of postural and locomotor control systems and their interactions in cats.Brain Dev. 1992; 14: S109-120
- Central mechanism of paradoxical sleep.in: Borbely J.A. Valax J.L. Sleep Mechanism: Experimental Brain Research. Springer-Verlag, Berlin-Heidelberg1984: 3-18
- The pathophysiology of the Rett syndrome from the standpoint of polysomnography.Brain Dev. 1990; : 55-60
- Supplementary motor area of the monkey's cerebral cortex: short- and long-term deficits after unilateral ablation and the effects of subsequent callosal section.J Neurosci. 1984; : 918-929
- Mirror movement due to the medial frontal lobe lesion (in Japanese).Rinsho Shinkeigaku (Tokyo). 1995; : 14-17
- Hereditary progressive dystonia with marked diurnal fluctuation and dopa-responsive dystonia. Pathognomonic clinical features.in: Segawa M. Nomura Y. Age-Related Dopamine-Dependent Disorders. Monogr Neural Sci. Karger, Basel1995: 10-24
- The Basal Ganglia.in: Kandel E.R. Schwartz J.H. Jessel T.M. 4th edition. Principles of Neuronal Science. McGraw-Hill, New York2000: 853-867
- Alterations in dopaminergic function in Rett syndrome.Neuropediatrics. 1995; : 123-125
- Pathophysiology of Rett syndrome from the standpoint of early catecholamine disturbance.Eur Child Adoles Psychiat. 1997; 6: 56-60
- New evidence for neurotransmitter influences on brain development.Trends Neurosci. 1997; : 269-274
- Impaired growth of the cerebral cortex of rats treated neonatally with 6-hydroxydopamine under different environmental conditions.Neurosci Lett. 1983; : 13-17
- Neurological model of infantile autism (In Japanese) No No Kagaku (Tokyo). 1998; : 169-175
- Hereditary progressive dystonia with marked diurnal fluctuation.Brain Dev :22(Suppl. 2000; 1: S65-S80
- Integration of posture and locomotion in acute decerebrate cats and in awake, freely moving cats.Progr Neurobiol. 1987; : 161-195
- Chemical activation of the mesencephalic locomotor region.Brain Res. 1985; : 43-54
- Excitotoxic lesions of the pedunculopontine tegmental nucleus produce contralateral hemiparkinsonism in the monkey.Neurosci Lett. 1997; : 111-114
- Rett syndrome: a disorder affecting early brain development.Ann Neurol. 1997; : 3-10
- A functional role for REM sleep in brain maturation.Behav Brain Res. 1995; : 1-11
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© 2001 Elsevier Science B.V. Published by Elsevier Inc. All rights reserved.
