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- CLINICA NEUROL, 42: 1069－1072, 2002
- Vol.42 No.11 contents
The 43rd Annual Meeting of the Japanese Society of Neurology
Educational Lecture II:
Differential diagnosis of spinocerebellar ataxia
Hidenao Sasaki, M.D.
Department of Neurology, Hokkaido University Graduate School of Medicine
Spinocerebellar ataxia (SCA) is a group of heterogeneous disorders. In Japan, approximately 60% of SCA consist of sporadic disorders, and the rest mostly consists of a variety of late-onset dominant disorders. In the latter, MJD, SCA6, DRPLA, SCA1 and SCA2 are frequent in this order, and others are rare. All these disorders are caused by unstable expansion of CAG repeat in the coding region of each responsible gene. Among those disorders, SCA6 manifests late-onset pure cerebellar ataxia and frequently associated with positioning vertigo. In other disorders, phenotype variation, clinical severity, and onset of age are known to correlate inversely with the CAG repeat size. Such variation even in a given disorder is often difficult to apply single criteria to diagnose the disorder based on its clinical findings alone.
MSA is a major disorder of sporadic SCA. Signs of cerebellar ataxia, parkinsonism, autonomic disturbance are incorporated into current diagnostic criteria. However, cases meeting the criteria of autonomic disturbances are confined to the advanced stage of the illness or rare cases starting with obvious dysautonomia. These problems indicate that the criteria need further adjustment.
(CLINICA NEUROL, 42: 1069－1072, 2002)
key words: spinocerebellar ataxia, triplet repeat disorder, anticipation, differential diagnosis, diagnostic criteria
(Received: 29-May-02)
