Spinocerebellar ataxia 27B, late-onset

GAA-FGF14-related ataxia is a mid to late adult-onset slowly progressive cerebellar syndrome with predominant gait involvement. Median age at onset is 60 years (range: 21-87 years). Nearly 50% of individuals may first experience episodic manifestations including gait and limb ataxia, visual disturbances (diplopia, oscillopsia, and blurring), vertigo and/or dizziness, or dysarthria on average two to four years before the onset of progressive ataxia. Episodic symptoms may persist after the onset of progressive ataxia and may be triggered by alcohol intake and physical activity. Although some individuals eventually require assistance with mobility, use of a wheelchair is less necessary than in other common hereditary spinocerebellar ataxias (e.g., SCA1, SCA2, and SCA3). Dysarthria does not develop in all individuals and often remains mild to moderate. Cerebellar oculomotor signs, including downbeat nystagmus, horizontal gaze-evoked nystagmus, and impaired visual fixation suppression of the vestibuloocular reflex, are common. Unilateral or bilateral vestibular hypofunction and tremor of the upper limbs may occur. Age of onset and clinical presentation can vary within the same family.

Full text of GeneReview (by section):

Summary

Diagnosis

Clinical Characteristics

Genetically Related (Allelic) Disorders

Differential Diagnosis

Management

Genetic Counseling

Resources

Molecular Genetics

Chapter Notes

References

Authors:

David Pellerin

Matt Danzi

Mathilde Renaud

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