Identification of an in-frame homozygous KIF1A variant causing a mild SPG30 phenotype in a Korean family

SPG30 is a newly categorized type of HSP caused by variants in the kinesin family member 1A gene (KIF1A). Advances in next-generation sequencing have resulted in a limited number of studies describing the clinical, electrophysiological, and radiological features of HSP, with variable manifestations. Most known pathogenic KIF1A variants affect the motor domain, although some rare pathogenic variants have been identified that affect the non-motor domain. Here, we report a Korean family with a rare homozygous autosomal-recessive form of SPG30. A 59-year-old man and his father presented with an uncomplicated, mild SPG30 phenotype, characterized by a progressive, spastic gait. Familial co-segregation analysis revealed a pathogenic c.2751_2753delGGA KIF1A variant that affects the non-motor domain. Our case broadens the genetic and clinical variability of SPG30, warranting similar studies to consolidate the pathogenicity of SPG30.