TYR and microphthalmia: Microphthalmia-associated transcription factor-M functions in melanocyte differentiation and survival, and directly activates the promoters of genes, including tyrosinase, that are required for pigment production (Bentley et al, 1994; Hemesath et al, 1994; Yavuzer et al, 1995; Yasumoto et al, 1997).