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Spinocerebellar Ataxia 38

Spinocerebellar Ataxia 38

Patient Information

Characteristics

Background and History

This heritable condition results from a gene mutation that leads to progressive degeneration of specific areas of the brain controlling balance, gait and eye movements. 

Clinical Correlations

By age 40 years most individuals have difficulty sitting still and walking.  These symptoms worsen slowly and some need walking assistance by the age of 50.  Slurred speech (dysarthria) is often noted about the same time.  Nearly all patients have the to-and-fro motion of ‘dancing eyes’ (nystagmus) but nothing is known about vision.  A few complain of sensory changes such as alterations in touch and muscle weakness has been noted in several individuals as well.

Genetics

Inheritance

This is an autosomal dominant condition passed directly from parent to child with a 50% probability.

Pedigree

Autosomal dominant

Autosomal dominant disorders require only one mutation for the disease to be expressed.  Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease.  It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).

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Sample pedigree of autosomal dominant inheritance

Autosomal dominant inheritance leads to a vertical pattern of transmission

Diagnosis and Prognosis

The diagnosis is most likely to be made by a neurologist.  No treatment is available but patients may benefit from physical therapy and devices for mobility assistance.  Longevity does not seem to be impacted.

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