KIF1C Variants Are Associated with Hypomyelination, Ataxia, Tremor, and Dystonia in Fraternal Twins

Abstract

<strong>Background:</strong> <em>KIF1C</em> (Kinesin Family Member 1C) variants have been associated with hereditary spastic paraplegia and spastic ataxia. <strong>Case report:</strong> We report fraternal twins presenting with cerebellar ataxia and dystonic tremor. Their brain MRI showed a hypomyelinating leukoencephalopathy. Whole exome sequencing identified a homozygous <em>KIF1C</em> variant in both patients. <strong>Discussion:</strong> <em>KIF1C</em> variants can manifest as a complex movement disorder with cerebellar ataxia and dystonic tremor. <em>KIF1C</em> variants may also cause a hypomyelinating leukoencephalopathy.