Spastic Paraplegia 74

Clinical Characteristics
Ocular Features: 

Onset of visual impairment occurs at ages of 10-14 years with optic pallor evident on fundoscopy. MRI imaging reveals physical atrophy of the optic nerve.  Visual acuity ranges from 0.5 to finger counting.  Visual field defects include central scotomas and peripheral concentric constriction.

Systemic Features: 

Symptoms consisting of a spastic gait and distal sensory impairment usually appear in the first decade and are slowly progressive.  Increased deep tendon reflexes and extensor plantar responses may be present at that time but later distal leg muscle atrophy and pes cavus appear.  The ankle reflexes later disappear.  Cognitive function is normal and adults are able to lead an independent life.

Nerve conduction studies in 4 individuals showed reduced muscle action potentials and velocity while sensory conduction was normal.  Cerebellar atrophy along with an attenuated corpus callosum and cervical spinal cord atrophy was noted on MRI imaging in one of 3 studied patients.

Genetics

A homozygous splice site mutation in IBA57 (1q42) has been found to segregate with this condition in a large consanquineous Arab family.

Treatment
Treatment Options: 

No treatment is known for the basic disease but physical therapy and low vision aids are likely beneficial.

References
Article Title: 

Fe S protein assembly gene IBA57 mutation causes hereditary spastic paraplegia

Lossos A, Stumpfig C, Stevanin G, Gaussen M, Zimmerman BE, Mundwiller E, Asulin M, Chamma L, Sheffer R, Misk A, Dotan S, Gomori JM, Ponger P, Brice A, Lerer I, Meiner V, Lill R. Fe/S protein assembly gene IBA57 mutation causes hereditary spastic paraplegia. Neurology. 2015 Feb 17;84(7):659-67.

PubMed ID: 
25609768

References

Lossos A, Stumpfig C, Stevanin G, Gaussen M, Zimmerman BE, Mundwiller E, Asulin M, Chamma L, Sheffer R, Misk A, Dotan S, Gomori JM, Ponger P, Brice A, Lerer I, Meiner V, Lill R. Fe/S protein assembly gene IBA57 mutation causes hereditary spastic paraplegia. Neurology. 2015 Feb 17;84(7):659-67.

PubMedID: 25609768