Ataxia and Polyneuropathy, Adult-Onset

Clinical Characteristics
Ocular Features: 

This condition has its onset in young adults.  Early ocular signs are gaze-evoked horizontal nystagmus and defective ocular pursuit movements with the full range of extraocular movements.  Some patients but not all have optic atrophy.  Ptosis is not present.

Systemic Features: 

Gait disturbances have their onset in the first or second decades of life.  The gait may be broad-based.  Intermittent hemiparesis with headache, nausea and vomiting has been reported in some individuals.  Absent ankle jerks and extensor plantar responses have been noted but general muscle tone and strength is usually normal.   An axonal sensorimotor neuropathy may be present in midlife as documented by nerve conduction studies.  MRIs of the brain may reveal cerebellar atrophy.

Mild cognitive problems have been reported in a few individuals.

Genetics

This is a mitochondrial disorder secondary to mutations in the mitochondrial MTATPA6 gene.

Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

References

Craig K, Elliott HR, Keers SM, Lambert C, Pyle A, Graves TD, Woodward C, Sweeney MG, Davis MB, Hanna MG, Chinnery PF. Episodic ataxia and hemiplegia caused by the 8993T->C mitochondrial DNA mutation. J Med Genet. 2007 Dec;44(12):797-9.

PubMedID: 18055910

Rantamaki MT, Soini HK, Finnila SM, Majamaa K, Udd B. Adult-onset ataxia and polyneuropathy caused by mitochondrial 8993T-->C mutation. Ann Neurol. 2005 Aug;58(2):337-40.

PubMedID: 16049925