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Waardenburg Syndrome Mutations in the EDN3, EDNRB, MITF, PAX3, SNAI2, and SOX10 are the genes that are affected from Waardenburg Syndrome. Some of these genes are involved in the making of melanocytes, which makes the pigment melanin. Melanin is an important pigment in the development of hair, eye color, skin, and functions of the inner ear. So the mutation of these genes can lead to abnormal pigmentation and hearing loss (Kumar). PAX3 and MTIF gene mutation occurs in type I and II (WS1 and WS2). Type III (WS3) shows mutations of the PAX3 gene also. SOX10, EDN3, or EDNRB gene mutations occur in type IV. Type IV (WS4) can also affect portions of nerve cell development that potentially can lead to intestinal issues. Inheritance: Types I and III inheritance of this trait is autosomal dominant. There is a 50% chance that a child of an affected parent will be affected. Symptoms vary and so the extremity of symptoms cannot be determined. Types II and IV is autosomal recessive, symptoms are not definite they vary just as the other type’s symptoms will. A study was done on a rare case of a double heterozygous child with each parent having only single mutations in MTIF or PAX3. The affect of double heterozygous mutations in the genes MTIF and PAX3 in WS1 and WS2 can increase the pigment-affected symptoms. It leads to the conclusion that the double mutation of MTIF is associated with the extremity of Waardenburg Syndrome and may affect the phenotypes or symptoms of the syndrome (Yang). Specifics: Type I is associated with more permanent hearing loss as for Type III over time hearing will be lost. Both are similar physically but there is no way to diagnose by eye, but to distinguish differences genetic testing is needed. Type II is most common out of all and its phenotypes are permanent hearing loss and heterochromia iridis (two different colored eyes) While Type IV has most of the symptoms associated with type II patients also tend to develop Hirschsprung's disease, intestinal problems, which can be life threatening and surgery is needed for enlarged colon and failure to pass feces Sources Baral, Viviane, et al. “Screening of MTIF and SOX10 Regulatory Regions In Waardenburg Syndrome Type 2. “Plos ONE 7.7 (2012): 1-8. Academic Search Premier. Web. 4 Apr. 2014.

Kumar, Sudesh, and Kiran Rao. “Waardenburg Syndrome: A Rare Genetic Disorder, A Report of Two Cases.” Indian Journal of Human Genetics 18.2 (2012): 254-255. Academic Search Premier. Web. 4 Apr. 2014.

Yang, T, et al. “Double Heterozygous Mutations Of MTIF and PAX3 Result in Waardenburg Syndrome With Increased Penetrance In Pigmentary defects.” Clinical Genetics 83.1 (2013): 78-62. Academic Search Premier. Web. 3 Apr. 2014.