Abstract
The complexities of the autonomic nervous system (ANS) and its intimate relationship with sensory function are especially well illustrated in the group of genetic disorders known as hereditary sensory and autonomic neuropathies (HSAN). Each HSAN disorder is caused by a different genetic error affecting a specific aspect of small fiber development and/or maintenance resulting in variable phenotypic expression. With the exception of HSAN type I, which is a dominant disorder presenting in the second decade, the other HSAN are autosomal recessive disorders whose mutations impede normal neural crest migration and differentiation and result in decreased neuronal populations. Therefore signs are usually present within the first year of life. For each HSAN type, penetrance is complete but there can be marked variability in expression. Decreased analgesia is characteristic of all HSANs, whereas the degree and type of autonomic dysfunction differs among the HSANs.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Emery and Rimoin's Principles and Practice of Medical Genetics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
