Waardenburg Syndrome (WS) is an autosomal-dominant disorder characterized by 
sensorineural hearing loss and pigmentary abnormalities of the eyes, hair, and 
skin. Microphthalmia-associated transcription factor (MITF) gene mutations 
account for about 15% of WS type II (WS2) cases. To date, fewer than 40 
different MITF gene mutations have been identified in human WS2 patients, and 
few of these were of Chinese descent. In this study, we report clinical findings 
and mutation identification in the MITF gene of 20 Chinese WS2 patients from 14 
families. A high level of clinical variability was identified. Sensorineural 
hearing loss (17/20, 85.0%) and heterochromia iridum (20/20, 100.0%) were the 
most commonly observed clinical features in Chinese WS2 patients. Five affected 
individuals (5/20, 25.0%) had numerous brown freckles on the face, trunk, and 
limb extremities. Mutation screening of the MITF gene identified five mutations: 
c.20A>G, c.332C>T, c.647_649delGAA, c.649A>G, and c.763C>T. The total mutational 
frequency of the MITF gene was 21.4% (3/14), which is significantly higher than 
the 15.0% observed in the fair-skinned WS2 population. Our results indicate that 
MITF mutations are relatively common among Chinese WS2 patients.