SOX10 and Waardenburg syndrome type 2: While the percentages of WS2 probands with heterochromic iridis, premature graying of the hair or patchy de-pigmentation of the skin were not significantly different between those with SOX10 and MITF mutations (P > 0.05), excessive freckle (as shown in previous reports7, 8), a common WS2 phenotype in Chinese Han patients, was frequent in WS2 probands with MITF mutations (7/10) but absent in those with SOX10 mutations (0/13, P = 4.9 × 10−4).