Eye movement and optic nerve markers in spastic paraplegia 7

Mutations in Spastic paraplegia 7 (SPG7, OMIM# 607259) have first been associated with a rare autosomal recessive form of hereditary spastic paraparesis (HSP). However, in the past years both dominant and recessive SPG7 mutations have been increasingly recognized and associated with cerebellar involvement and ophthalmic findings. Interestingly, ophthalmic findings occasionally are described as the earliest manifestation: there are a few reports of childhood-onset optic nerve atrophy in SPG7 with progressive visual loss, preceding other manifestations by many years. 

The detection of early markers of disease in mildly symptomatic stages in SPG7 could be fundamental to start therapeutic interventions when the cerebellar reserve is still active. Quantitative measurements of eye movement, Optical coherence tomography (OCT) have already demonstrated to be solid and reproducible indexes of cerebellar dysfunction and optic nerve damage respectively, however, they have never been correlated together as markers to assess and predict functional evolution.

In order to define new early disease biomarkers, we aim to perform a longitudinal study correlating the onset and severity of ocular manifestations by measurements of eye movement and OCT with ataxic symptoms in a large cohort of SPG7 patients harboring both dominant or recessive SPG7 mutations