Neuralgic Amyotrophy, a painful disorder of the nervous system
Hereditary Neuralgic Amyotrophy (HNA) is characterized by repeated attacks of pain in a shoulder, arm, and/or hand, followed by total or partial paralysis of the affected area. The pain and the loss of movement usually disappear within a couple of weeks, but sometimes recovery can take months or even several years. Many HNA patients also have particular facial features, such as eyes that are somewhat closer together, a fold in the upper eyelid that covers the inside corner of the eye, and sometimes a cleft palate.
HNA is a relatively rare disorder: the disease appears in some 200 families worldwide. There is also a non-hereditary form of HNA, called the Parsonage-Turner Syndrome. The clinical picture of this more frequently occurring form - 2 to 4 cases per 100,000 persons - is not distinguishable from that of the heritable form.
The attacks of pain are usually provoked by external factors such as vaccination, infection, operation, and even pregnancy or childbirth. By virtue of their genetic predisposition, carriers of the hereditary form of HNA run greater risk of having an attack. Its re-occurrence, and the fact that the disease is provoked by environmental factors, make this disorder unique in the group of peripheral nervous system disorders. Therefore, HNA is a genetic model for more frequently occurring disorders such as the Parsonage-Turner Syndrome and neurological disorders like Guillain-Barr?Syndrome.<
Source:VIB, Flanders Interuniversity Institute of Biotechnology