Spinocerebellar Ataxia 42

Clinical Characteristics
Ocular Features: 

 Saccadic eye movements with nystagmus and diplopia have been reported (7 of 10 reported patients).

Systemic Features: 

Cerebellar signs usually have their onset in midlife or later with slow progression.  Most patients are mildly to moderately disabled.  Dysarthria, dysphagia, and a spastic gait are experienced by the majority of individuals.  Hyperreflexia and a positive Babinski sign are commonly presently.  Mild cognitive impairment and depression have been seen in a minority of patients.

Brain MRIs show cerebellar hemispheric and vermian atrophy.  The cerebral cortex appeared histologically normal in one deceased patient.


This disorder is caused by heterozygous mutations in the CACNA1G gene (17q21.33).

Treatment Options: 

No treatment has been reported.

Article Title: 


Morino H, Matsuda Y, Muguruma K, Miyamoto R, Ohsawa R, Ohtake T, Otobe R, Watanabe M, Maruyama H, Hashimoto K, Kawakami H. A mutation in the low voltage-gated calcium channel CACNA1G alters the physiological properties of the channel, causing spinocerebellar ataxia. Mol Brain. 2015 Dec 29;8:89.

PubMedID: 26715324

Coutelier M, Blesneac I, Monteil A, Monin ML, Ando K, Mundwiller E, Brusco A, Le Ber I, Anheim M, Castrioto A, Duyckaerts C, Brice A, Durr A, Lory P, Stevanin G. A Recurrent Mutation in CACNA1G Alters Cav3.1 T-Type Calcium-Channel Conduction and Causes Autosomal-Dominant Cerebellar Ataxia. Am J Hum Genet. 2015 Nov 5;97(5):726-37.

PubMedID: 26456284