[Autosomal dominant spinocerebellar degeneration--new forms and pathomechanisms].

In our country, hereditary spinocerebellar degeneration accounted for approximately 30% of the total cases. Most of them are autosomal dominant and include more than 20 diseases. The outlines of some new members, namely autosomal dominant cortical cerebellar atrophy linked to chromosome 16 (16q-ADCCA), SCA14, an ataxia caused by FGF14 mutation and a form of neuroferritinopathy were described. The etiology of many autosomal dominant SCDs has been identified as the abnormal expansion of CAG repeat. The latter three diseases are caused by missense mutations of the causative genes, which clearly shows the presence of other new mechanisms of cerebellar degeneration than repeat expansion. 16q-ADCCA is the most frequent after Machado-Joseph disease and SCA6 according to our genetic diagnosis of 185 SCD patients. The disease is characterized by Purkinje cell degeneration and atrophy with somatic sprouts as well as the halo-like structure surrounding the soma. The halo is positive for synaptophysin. These features are so unique that 16q-ADCCA may be diagnosed by neuropathology alone.