Prognostic factors and clinical outcome in a rare form of spastic paraplegia (Spoan syndrome): a 10-year follow-up

Background: Spastic paraplegia, optic atrophy and neuropathy (Spoan syndrome) is an autosomal recessive disease with approximately 70 cases recorded in Brazil and Egypt. Methods: This is a prospective longitudinal study performed with 47 patients affected with Spoan syndrome of seven communities of Rio Grande do Norte (Brazil) to investigate prognostic factors and clinical outcome based on comparative data obtained from a 10-year follow-up. Results: The mean age of the participants was 47.21±12.42 years old, and the mean ages at loss of ambulation and hand function were 10.78±5.55 and 33.58±17.47 years old, respectively. Spearman’s correlation analysis between the score on the Modified Barthel Index and the investigated variables evidenced statistical significance for age (p<0.001) and right- and left-hand grip strength (p=0.042 and p=0.021, respectively). Statistical significance was not evidenced for the remainder of the variables, including age at onset of symptoms (p=0.634), age at loss of ambulation (p=0.664) and age at loss of hand function (p=0.118). Conclusions: Our analysis allows asserting that the participants exhibited slight dependence until age 35. The greatest losses occurred from ages 35 to 41, and starting at 50, practically all patients become completely dependent. In fact, age is the main prognostic factor of impaired motor function among Spoan syndrome patients.