Novel KIF5A variant in a patient with early-onset levodopa-responsive Parkinson's syndrome.

We present the case of a male in his mid-30s with a progressive complex neurological phenotype primarily characterised by levodopa-responsive parkinsonism with motor fluctuations as well as gait ataxia, peripheral neuropathy and finally also spastic paraplegia. Genetic analysis identified a novel heterozygous variant in the KIF5A gene: c.937G>A (p.Glu313Lys). This variant is genetically classified as likely pathogenic. Other pathogenic mutations in the KIF5A gene are associated with hereditary spastic paraplegia type 10, Charcot-Marie-Tooth disease type 2 and amyotrophic lateral sclerosis. We discuss the clinical, genetic and prognostic implications of this finding.