Pioneers for the Basic Understanding of Usher syndrome

After the first description of the inherited nature of bimodal deaf-blindness disease in mid nineteenth century by pioneering ophthalmologists Albrecht von Graefe (May 22, 1828 ± July 20, 1870) and Richard Liebreich (June 30, 1830 - January 19, 1917) followed by its confirmation in early twentieth century from a larger number of patients by another pioneer ophthalmologist Charles Howard Usher (March 02, 1865 - March 03, 1942) the pathogenesis of Usher syndrome (USH) was studied unsuccessfully by cytological methods. In 1922 aBritish geneticist Julia Bell described the phenotypic heterogeneity in deaf-blind patients and this served as a base for the standardization of USH types by S.L.H. Davenport and G.S. Omenn in 1977. To date nine causative genes and twelve chromosomal loci have been described and some of the causative genes are yet to be identified. In spite of the knowledge of the genetic heterogeneity the clinical classification of Usher syndrome into USH type 1, 2, and 3 is still used.