Three Spinocerebellar Ataxia Type 2 Siblings with Ataxia, Parkinsonism, and Motor Neuronopathy

Abstract

Spinocerebellar ataxia type 2 (SCA2) represents a family of dominant neurodegenerative disorders that results from CAG expansion repeat mutations. The phenotype consists of some common features, most notably progressive ataxia. We describe three siblings with SCA2, manifesting parkinsonism and ataxia in the first sibling, juvenile parkinsonism in the second and motor neuronopathy in the third. Genetic examination revealed expansion to 42, 43, and 42 CAG repeats. There was no relationship between the number of repeats and phenotype. The SCA2 gene should be studied in families with heterogeneous neurodegenerative disorders, including motor neuron disease.

Atypical presentation of late‐onset Tay‐sachs disease

“…Although cerebellar atrophy would be expected as a feature in either of these conditions, it is possible that it was not prominent early in the course of her disease. Some SCAs, as well as autosomal recessive ataxias, may overlap with motor neuron disease: SCA 2 may present with progressive ataxia, parkinsonism and motor neuropathy; SCA 3 typically affects the cerebellar, pyramidal, extrapyramidal, motor neuron, and oculomotor systems; SCA 36 may show adult‐onset truncal and limb ataxia, dysarthric ataxia, hyperreflexia, fasciculations, and atrophy; and in SCAR8 upper and lower motor involvement may precede the development of cerebellar ataxia by years . Of interest, ataxia‐telangiectasia may include pure distal SMA in the absence of ataxia …”

Spinocerebellar ataxia type 2 presenting with rapidly progressing muscle weakness and muscular atrophy

“…The number of CAG repeat lengths in these cases was more than 32, as in the present case (37). [6][7][8][9] In SCA2, the neuropathological findings of severe loss of anterior horn cells in the spinal cord (thoracic cord: 27-64% loss, lumbar cord: 33-83% loss), and degeneration of the corticospinal tract, posterior funiculus and dorsal root ganglions have been reported. 10 Therefore, an anterior horn cell lesion might have been present in this individual.…”