West Nile Virus
White Piedra
Wilms Tumor (cancer of childhood)
Waldenstrom macroalbuminuria
Whiplash (more of an injury than a disease)
Werdnig-Hoffman disease
Williams syndrome
Wilsons Disease
West Syndrome (some would say a syndrome is not a disease)
White Sponge Nevus
Wooly hair nevus
Weber-Christian disease
Winchester Syndrome
Wrinkly skin syndrome
Wildervanck syndrome
Waardenburg Syndrome
Woronoff's Ring
Wende-Bauckus Syndrome
Watson syndrome