Mouse of the Month
Mitfmi-bw mutant mouse
A model for Waardenburg syndrome type 2
Targeted mutation : Mitf, Chr. 6
Waardenburg syndrome type 2 (WS2) is an autosomal dominant disorder characterized by a combination of pigmentary and auditory abnormalities in human. Approximately 20% of WS2 cases are associated with mutations in the gene encoding the microphthalmia-associated transcription factor (Mitf). Mitf plays a critical role in the development of melanocytes, mast cells, osteoclasts and pigmented epithelium. The Mitfmi-bw allele is one of the oldest known among white spotting mutations, and homozygous mice for the Mitfmi-bw mutation display a white coat with black eyes (figure). In this allele, a L1 retrotransposable element was inserted into intron 3. This strain is useful as an animal model for Waardenburg syndrome type 2 (WS2).