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Tietz syndrome, also called Tietz albinism-deafness syndrome or albinism and deafness of Tietz, is an autosomal dominant congenital disorder characterized by deafness and leucism. It is caused by a mutation in the microphthalmia-associated transcription factor (MITF) gene. Tietz syndrome was first described in 1923.

Cause and Genetics
Tietz syndrome is caused by mutations in the MITF gene, located on human chromosome 3p14.1-p12.3. It is inherited in an autosomal dominant manner. This indicates that the defective gene responsible for a disorder is located on an autosome (chromosome 3), and only one inherited copy of the defective gene is sufficient to cause the disorder.

Mutations to the MITF gene are important because it codes for the microphthalmia-associated transcription factor protein. Transcription factors are in charge of controlling the expression of certain genes downstream of their transcription sites on the DNA strand. In the case of Tietz Syndrome, the MITF gene contains a mutation which inhibits its ability to successfully bind to the DNA strand and promote expression of the genes under its control. This results in impaired development of melanocyte cells and restricted melanin production throughout the body. The reduced number or complete loss of melanocyte cells of the inner ear bring about the hearing impairments associated with Tietz syndrome, while the reduction in melanin production is responsible for the hypopigmentation and lack of hair colour found in individuals with the mutatation.

Signs and Symptoms
Although individuals are born with ‘snow white’ skin at birth, they are able to freckle as well as tan slightly, showing that there is not a complete absence of melanocytes in their skin.
 * Blonde to white hair (including eyebrows and eyelashes)
 * Extremely fair skin at birth]].
 * Blue eyes
 * Hypopigmented fungi
 * Bilateral, profound hearing loss

History
Walter Tietz first documented Tietz syndrome in 1963 when a father brought in his albino son, who was thought to also be deaf, to Tietz's pediatric practrice. The son as well as his mother and grandmother were confirmed to have complete deafness in addition to their albinism, which was unusual because there was no known disease with these linked traits. Tietz correctly differentiated this new disease from Waardenberg Syndrome, the known disease at the time responsible for linked albinism and deafness, due to the complete penetrance of the disease as well as the lack of patchy pigmentation and heterochromia.

It was later discovered that these differences between Tietz and Waardenberg syndrome are because of varying functionality of the MITF gene. With the point mutation responsible for Tietz syndrome leaving the gene nonfunctional while the mutation responsible for Waardenberg syndrome type 2 leaves the MITF gene with some functionality.