Spastic Ataxia 4, mtPAP Deficiency

Background and History: 

This is a very rare congenital neurological disorder affecting balance, speech, movement of the arms, legs, and tongue.  It is associated with abnormalities of the optic nerve that carries visual signals to the brain.

Clinical Correlations: 

Children with this condition have difficulty with balance almost from birth.  They also are slow to walk and talk which becomes more of a problem as they grow older.  The arms and legs seem stiff, speech sounds slurred, and swallowing may become a problem.  Balance as in sitting and walking is a special problem.  Children in grade school require special education assistance but there is no evidence that there is deterioration of mental capabilities.  Nothing is known about the level of vision but in spite of evidence for damage to the optic nerve that transmits visual images from the eye to the brain, individuals seem to function well at home and in school.  However, some children have 'dancing eyes', which is often associated with some decrease of vision.


Two families with multiple affected sibs have been reported with a pattern consistent with autosomal recessive inheritance.  Mutations (changes) in both copies of a specific gene are responsible.  Parents who carry a single copy are clinically normal but they can expect a risk of 25% of each of their children having this condition.

Diagnosis and Prognosis: 

The diagnosis is likely to be made by a neurologist or pediatrician in a child who is slow to walk and speak.  No treatment is available but children can benefit from speech and physical therapy as well as from special education assistance.  There is no evidence of deterioration in mental function.  Motor functions, especially gait and balance, however, become progressively more difficult. Adults remain able to ambulate and care for themselves with minimal assistance.

Additional Information
Autosomal recessive