KIF1A and Global developmental delay: WES was a valid test to diagnose complex phenotypes in a patient with severe early-onset neuropathy, thyroid agenesis, and polydactyly that had a missense variant in the PMP22 gene consistent with Dejerine-Sottas disease, and another patient with sensory axonal neuropathy, global developmental delay, optic atrophy, and cerebellar ataxia was identified with de novo variant in the KIF1A gene [36].