Traffic Jams in the Brain: How Kinesin Dysfunction Shapes Neurodevelopmental Disorders.

The development and maintenance of the nervous system depend on a tightly regulated intracellular transport network in which kinesin superfamily (KIF) motor proteins drive microtubule-based delivery of synaptic vesicle precursors, organelles, mRNAs, and signaling components along axons and dendrites. Disruption of this machinery underlies a clinically heterogeneous spectrum of neurodevelopmental disorders (NDDs), including intellectual disability, epilepsy, autism spectrum disorder, microcephaly, malformations of cortical development, spasticity, and axonal neuropathy. Here, we synthesize current knowledge on how kinesin dysfunction shapes neurodevelopment. We outline the physiological roles of kinesins in neuronal polarity, organelle and mitochondrial positioning, synaptogenesis, and progenitor division, and survey principal disease-associated genes, including KIF1A, KIF5A, KIF7, KIF11, KIF2A, KIF5C, and emerging members such as KIF14, KIF15, and KIF16B. We detail how distinct pathogenic mechanisms, such as loss of motility, impaired cargo coupling, motor hyperactivity, mitotic spindle defects, and disrupted ciliary signaling, converge on shared cellular endpoints, and how tubulin isotypes and posttranslational modifications further modulate motor output. In this review, we discuss translational implications, including variant-resolved diagnosis and precision strategies to restore transport, dampen pathological hyperactivity, or stabilize the microtubule track. Collectively, these advances reframe kinesinopathies as mechanistically stratified disorders of neuronal transport.