A dominantly inherited syndrome associated with hypopigmentation, heterochromia 
irides, colobomatous eyes and bilateral hearing loss has been ascertained in 
Fleckvieh cattle (German White Fleckvieh syndrome). This syndrome has been 
mapped to bovine chromosome (BTA) 22 using a genome-wide association study with 
the bovine high density single nucleotide polymorphism array. An R210I missense 
mutation has been identified within microphthalmia-associated transcription 
factor (MITF) as responsible for this syndrome. The mutation is located in the 
highly conserved basic region of the protein and causes a negative-dominant 
effect. SOX10 and PAX3 promoter binding site mutations in MITF could be ruled 
out as causative for the German White Fleckvieh syndrome. Molecular 
characterization of this newly detected bovine syndrome means a large animal 
model is now available for the Tietz syndrome in humans.