Waardenburg syndrome (WS) is a disorder characterized by varying degrees of deafness and minor defects in structures arising from neural crest, including pigmentation anomalies of eyes, hair, and skin. WS is classified into four clinical and genetic phenotypes.

An inability to perceive odors. This is a general term describing inability to smell arising in any part of the process of smelling from absorption of odorants into the nasal mucous overlying the olfactory epithelium, diffusion to the cilia, binding to olfactory receptor sites, generation of action potentials in olfactory neurons, and perception of a smell.