caa a22 4500 475786955 CHVBK 20180406123701.0 cr unu---uuuuu 170329e20001201xx s 000 0 eng 10.1007/PL00014409 doi (NATIONALLICENCE)springer-10.1007/PL00014409 Read Andrew P. Department of Medical Genetics, St Mary's Hospital, Manchester M13 0JH, UK e-mail: Andrew.Read@man.ac.uk Tel.: +44-161-2766601; Fax: +44-161-2766606, GB aut Hereditary deafness: lessons for developmental studies and genetic diagnosis [Elektronische Daten] [Andrew P. Read] Hereditary deafness is highly heterogeneous genetically, with over 100 loci so far identified. Routine diagnostic mutation screening can be done only when a candidate gene has been identified, and preferably a candidate mutation. For syndromic forms of hearing loss it is often possible to predict the gene involved. Non-syndromic loss is much more intractable to diagnostic mutation screening because of the extensive locus heterogeneity. However, mutations in the connexin 26 (GJB2) gene and the mitochondrial m.1555A > G mutation are sufficiently frequent in some populations to justify mutation testing. Identifying the genes mutated in syndromic hearing loss can help delineate developmental pathways. Conclusion The example of Waardenburg syndrome is used to illustrate how unravelling developmental pathways can be more complicated than defining metabolic pathways through biochemical defects. Developmental genes tend to be organised into networks rather than linear pathways, and transcription factors act in a combinatorial manner. This makes developmental pathways harder to unravel genetically than metabolic pathways. Springer-Verlag Berlin Heidelberg, 2000 Key words Connexin 26 nationallicence Hearing loss nationallicence Melanocyte nationallicence Neural crest nationallicence Waardenburg syndrome nationallicence https://doi.org/10.1007/PL00014409 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/PL00014409 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Read Andrew P. Department of Medical Genetics, St Mary's Hospital, Manchester M13 0JH, UK e-mail: Andrew.Read@man.ac.uk Tel.: +44-161-2766601; Fax: +44-161-2766606, GB aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer